Helms Credit - www.spacefacts.de

Personal: Female, Single. Born in Charlotte, North Carolina, USA. PhD US Air Force US Air Force

Astronaut Career

Astronaut Group: NASA Group 13 - 1990. Inactive Entered space service: 17 January 1990. Left space service: 28 July 2002. Number of Flights: 5.00. Total Time: 210.96 days. Number of EVAs: 1.00. Total EVA Time: 0.37 days.

NAME: Susan J. Helms (Lieutenant Colonel, USAF)

NASA Astronaut

PERSONAL DATA:

Born February 26, 1958, in Charlotte, North Carolina, but considers Portland, Oregon, to be her hometown. She enjoys jazz piano and other musical activities, jogging, traveling, reading, flying, and cooking. Plays keyboard for MAX-Q, a rock-n-roll band. Her parents, Lt. Col. (Ret., USAF) Pat and Dori Helms, reside in Albuquerque, New Mexico.

EDUCATION:

Graduated from Parkrose Senior High School, Portland, Oregon, in 1976; received a bachelor of science degree in aeronautical engineering from the U.S. Air Force Academy in 1980, and a master of science degree in aeronautics/astronautics from Stanford University in 1985.

ORGANIZATIONS:

Women Military Aviators; U.S. Air Force Academy Association of Graduates; Stanford Alumni Association; American Institute of Aeronautics and Astronautics (AIAA).

SPECIAL HONORS:

Recipient of the Distinguished Superior Service Medal, the Air Force Meritorious Service Medal, the Air Force Commendation Medal and the NASA Space Flight Medal. Named a Distinguished Graduate of the USAF Test Pilot School, and recipient of the R.L. Jones Award for Outstanding Flight Test Engineer, Class 88A. In 1990, she received the Aerospace Engineering Test Establishment Commanding Officer's Commendation, a special award unique to the Canadian Forces. Named the Air Force Armament Laboratory Junior Engineer of the Year in 1983.

EXPERIENCE:

Helms graduated from the U.S. Air Force Academy in 1980. She received her commission and was assigned to Eglin Air Force Base, Florida, as an F-16 weapons separation engineer with the Air Force Armament Laboratory. In 1982, she became the lead engineer for F-15 weapons separation. In 1984, she was selected to attend graduate school. She received her degree from Stanford University in 1985 and was assigned as an assistant professor of aeronautics at the U.S. Air Force Academy. In 1987, she attended the Air Force Test Pilot School at Edwards Air Force Base, California. After completing one year of training as a flight test engineer, Helms was assigned as a USAF Exchange Officer to the Aerospace Engineering Test Establishment, Canadian Forces Base, Cold Lake, Alberta, Canada, where she worked as a flight test engineer and project officer on the CF-18 aircraft. She was managing the development of a CF-18 Flight Control System Simulation for the Canadian Forces when selected for the astronaut program.

As a flight test engineer, Helms has flown in 30 different types of U.S. and Canadian military aircraft.

Selected by NASA in January 1990, Helms became an astronaut in July 1991. She is qualified for assignment as a mission specialist on future Space Shuttle flight crews. Her technical assignments to date include working RMS/robotics issues in the Mission Development Branch of the Astronaut Office, and as a CAPCOM (spacecraft communicator) for STS-57, STS-51, STS-58, STS-60 & STS-61. She is currently the Branch Chief for Payloads/Habitability for the Astronaut Office. A veteran of three space flights, Helms has orbited the Earth 544 times, traveled over 14 million miles, and has logged a total of 33 days, 20 hours, 17 minutes, and 17 seconds in space.

On her first mission, Helms flew on the crew of STS-54, January 13-19, 1993. The primary objective was the deploy of a $200-million NASA Tracking and Data Relay Satellite (TDRS-F). A Diffuse X-Ray Spectrometer (DXS) carried in the payload bay, collected over 80,000 seconds of quality X-ray data that will enable investigators to answer questions about the origin of the Milky Way galaxy. The crew demonstrated the physics principles of everyday toys to an interactive audience of elementary school students across the United States. A highly successful Extravehicular Activity (EVA) resulted in many lessons learned that will benefit Space Station Freedom assembly. Mission duration was 5 days, 23 hours, 38 minutes, 17 seconds.

On STS-64, September 9-20, 1994, Helms was the flight engineer for orbiter operations and the primary RMS operator aboard Space Shuttle Discovery. The major objective of this flight was to validate the design and operating characteristics of Lidar in Space Technology Experiment (LITE) by gathering data about the Earth's troposphere and stratosphere. Additional objectives included the deploy and retrieval of SPARTAN-201, a free-flying satellite that investigated the physics of the solar corona, and the testing of a new EVA maneuvering device. The Shuttle Plume Impingement Flight Experiment (SPIFEX) was used to collect extensive data on the effects of jet thruster impingement, in preparation for proximity tasks such as space station docking. Mission duration was 10 days, 22 hours, 51 minutes.

On STS-78, June 20 to July 7, 1996, Helms was the payload commander and flight engineer aboard Columbia, on the longest Space Shuttle mission to date. The mission included studies sponsored by ten nations and five space agencies, and was the first mission to combine both a full microgravity studies agenda and a comprehensive life science investigation. The Life and Microgravity Spacelab mission served as a model for future studies on board the International Space Station. Mission duration was 16 days, 21 hours, 48 minutes.

In completing three missions, Helms has orbited the Earth 544 times, traveled over 14 million miles, and has logged a total of 912 hours, 17 minutes, and 17 seconds in space.

• 13 January 1993 Flight: STS-54. Flight Up: STS-54. Flight Back: STS-54. Flight Time: 5.98 days.

• 9 September 1994 Flight: STS-64. Flight Up: STS-64. Flight Back: STS-64. Flight Time: 10.95 days.

• 20 June 1996 Flight: STS-78. Flight Up: STS-78. Flight Back: STS-78. Flight Time: 16.91 days.

• 19 May 2000 Flight: STS-101. Flight Up: STS-101. Flight Back: STS-101. Flight Time: 9.84 days.

• 8 March 2001 Flight: ISS EO-2. Flight Up: STS-102. Flight Back: STS-105. Flight Time: 167.28 days.

17 January 1990 - NASA Astronaut Training Group 13 selected.. The group was selected to provide pilot, engineer, and scientist astronauts for space shuttle flights.. Qualifications: Pilots: Bachelor's degree in engineering, biological science, physical science or mathematics. Advanced degree desirable. At least 1,000 flight-hours of pilot-in-command time. Flight test experience desirable. Excellent health. Vision minimum 20/50 uncorrected, correctable to 20/20 vision; maximum sitting blood pressure 140/90. Height between 163 and 193 cm.

Mission Specialists: Bachelor's degree in engineering, biological science, physical science or mathematics and minimum three years of related experience or an advanced degree. Vision minimum 20/150 uncorrected, correctable to 20/20. Maximum sitting blood pressure of 140/90. Height between 150 and 193 cm.. Reported to the Johnson Space Center in late July 1990 to begin their year long training. Chosen from 1945 qualified applicants, then 106 finalists screened between September and November 1989.

The next Shuttle crew to visit the ISS was finalized last week and includes Jim Voss, Susan Helms and Yuri Usachev - the second crew that will live aboard the ISS next year. They now will take an early 'peak' at their home during the STS-101 mission that will be commanded by Jim Halsell and piloted by Scott Horowitz. Rounding out the crew will be Mission Specialists Mary Ellen Weber and Jeff Williams. Atlantis is being readied at the Kennedy Space Center in Florida for the launch scheduled for no earlier than April 13.

While vehicle processing continues, mission planners are working on stowage and maintenance tasks that will be carried out on the 11-day flight. A spacewalk by Williams and Voss will include checking the position of a small crane mounted outside Zarya in addition to other tasks. The crane was installed during a spacewalk on the most recent Shuttle visit to the ISS. Plans call for Williams and Voss to ensure the crane is properly secured in its mounting socket.

Meanwhile, battery cycling continues on orbit with two of the six batteries currently in restoration mode, which is a procedure periodically carried out to maintain the life and capacity of each unit. At present, three batteries are supplying all the electrical needs of Station equipment.

STS-101 is designed to not only supply the Station with more logistics for use by future crews, but also to replace some of Zarya's aging batteries and other equipment in preparation for the arrival of the Zvezda service module in July. Presently, Zvezda is being readied for a launch between July 8-14.

Station managers plan to hold a meeting with the International Partners in the next week or two to finalize updates to the assembly sequence that will include launch target dates for the remainder of this year. That schedule will include Russian supply launches using the Progress resupply vehicles in addition to Shuttle logistics and assembly missions.

The first shuttle flight after the arrival of the Zvezda was approved to take place within a month after the service module's arrival. That STS-106 crew will be commanded by Terry Wilcutt with Scott Altman serving as pilot. Mission specialists include Dan Burbank, Rick Mastracchio, Ed Lu, Yuri Malenchenko, and Boris Morukov.

The International Space Station is in an orbit of 237 by 226 statute miles. Since the launch of Zarya in 1998, the ISS has completed more than 7,227 orbits. S

Atlantis' STS-101 mission not only provides an early look by three of its crew members at their future home, but also sets the stage for the arrival of the Zvezda service module set to launch on a Russian Proton rocket in mid July from the Baikonur Cosmodrome in Kazakhstan. Susan Helms, Jim Voss and cosmonaut Yuri Usachev will oversee maintenance tasks to restore the Zarya module's electrical power system to full capacity.

The three crew members were added to this mission for their unique abilities to step in on short notice to accomplish tasks for which they have already been training as the second crew to live alone next year on the ISS. Voss will join fellow crew member Jeff Williams in a space walk to replace a malfunctioning antenna on the Unity module and deliver additional components of a Russian crane to the outside of the station. The two astronauts also will check the current location of a small U.S. crane to ensure it is seated properly in its housing.

On orbit, the two components making up the International Space Station continue to operate in good health with electrical power management serving as the primary focus of flight controller attention. Zarya's automatic docking system that will be used to rendezvous and dock with Zvezda has been verified to be in good working condition following several tests over the course of the last few months. Kurs, as it's called, has two redundant systems and plans are being finalized as to which will serve as primary for the rendezvous and docking phase. Specific procedures are being developed as to the management of the station's power and communications systems during the final stages of the docking activities.

Earlier today in the California desert, an experimental spacecraft that is being considered for use as an emergency crew return vehicle from the ISS was tested for the fourth time. The X-38 was dropped from the wing of NASA's B-52 and touched down under the shadow of a huge parafoil. The next test of the craft at NASA's Dryden Flight Research Center is scheduled this summer.

The ISS continues to operate with no major systems failures as it circles the Earth every 92 minutes in an orbit of 232 by 217 miles. The station has completed more than 7,760 orbits since Zarya was launched in November 1998.

Launch is set to occur at about 4:15 p.m. Eastern time to perform life-extension maintenance tasks on the Zarya module, and to deliver supplies to the inside and outside of the Station for use by future crews.

Commander Jim Halsell has resumed full training activities after spraining his ankle a couple weeks ago and practiced landings in the Shuttle Training Aircraft last night. Joining Halsell on the mission are Pilot Scott Horowitz and Mission Specialists Mary Ellen Weber, Jeff Williams, Jim Voss, Susan Helms and Yuri Usachev. The latter three will focus their attention during the docked phase of the flight on repairing some equipment inside their future home.

Awaiting Atlantis' arrival, the International Space Station continues to operate with no major systems problems. Its electrical power system is being strategically managed to maximize the power required by operating systems inside the Zarya and Unity modules.

Meanwhile, in Moscow, the second and third stage engines have been delivered for final inspection and installation into the Proton rocket that will carry the next component of the ISS - the Zvezda service module - to orbit. Zvezda's launch remains slated between July 8 and 14 from the Baikonur Cosmodrome in Kazakhstan.

The current orbit of the ISS is 232 by 215 miles. The average decay of the Station's orbit is about 1-1 ½ miles per week. The altitude can be raised by using Zarya's thrusters, but will be unnecessary if Atlantis arrives later this month since the orbiter will perform an altitude reboost of the ISS before departing near the end of the flight. The ISS now has completed more than 7,860 orbits since Zarya was launched in November 1998.

Workers at the Kennedy Space Center in Florida have completed a swap-out of the power drive unit on the orbiter and will spend the next few days completing retests to verify the borrowed unit from Columbia is in good working order. At present there is no anticipated schedule impact to the April 24 launch.

Meanwhile, halfway around the world in Russia and Kazakhstan, work continues in preparation for Zvezda's launch atop a Proton launch vehicle. The Proton that will carry Zvezda into space currently is being assembled at its manufacturing plant at the Krunichev Space Center in Moscow. Its assembly is scheduled to be completed in mid May with delivery to the Baikonur Cosmodrome scheduled about two weeks later.

Awaiting the Proton's arrival at the launch site is the Zvezda service module, which will house life support systems, serve as the living quarters, and provide the ISS with command and control and reboost capability through the early assembly sequence. Zvezda's launch remains targeted to occur between July 8 and 14.

STS-101 will be commanded by Jim Halsell and piloted by Scott Horowitz. Joining them are Mission Specialists Mary Ellen Weber, Jeff Williams, Jim Voss, Susan Helms and Yuri Usachev. The seven-member crew will undergo their final physicals and wrap up training activities at the Johnson Space Center, Houston, this week prior to entering quarantine on Monday. The crew will fly to Florida next Friday, April 21, for the final three days of preparations prior to launch.

The current orbit of the ISS is 231 by 214 miles (372 x 344 kilometers). The average decay of the Station's orbit is about 1-1½ miles per week. While docked, Atlantis' reaction control system thrusters will be used to raise the orbit of the station by as much as 19 miles (about 30 kilometers). The actual orbit raising distance is calculated to 'place' the ISS at an altitude conducive to the rendezvous with Zvezda in late July. As of midday today, the station has circled the Earth more than 7,970 times since November 1998.

Final processing of the Shuttle is underway with the seven-member scheduled to arrive in Florida tomorrow at 3 p.m. East Coast time. Their arrival will be shown live on NASA Television.

The countdown begins tomorrow at 7 p.m. EDT leading toward a launch at the opening of a five-minute window at 4:15 p.m. Eastern.

Meanwhile, the on orbit Station is completing the final battery cycling of its four usable systems and will be in a good configuration for docking by the Shuttle next Wednesday. All systems are in good shape to support the rendezvous, docking and maintenance work scheduled throughout the STS-101 mission.

In addition to completing battery cycling, controllers will warm up the Unity module's shell so that it will be at the proper temperature when the Shuttle arrives. That activity should be completed before Monday's Shuttle launch.

At the Baikonur Cosmodrome in Kazakhstan, workers have completed electrical testing of the Zvezda service module, which is the next component of the ISS. Zvezda will be launched atop a Proton rocket in mid July. The ISS will dock with Zvezda about two weeks later near the end of July.

STS-101 will be commanded by Jim Halsell. Joining him on the crew are Pilot Scott Horowitz and Mission Specialists Mary Ellen Weber, Jeff Williams, Jim Voss, Susan Helms and Yuri Usachev.

The current orbit of the ISS is 229 by 213 miles (368 x 342 kilometers). The average decay of the Station's orbit is about 1-1½ miles per week. While docked, Atlantis' reaction control system thrusters will be used to raise the orbit of the Station by as much as 19 miles (about 30 kilometers). The actual orbit raising distance is calculated to position the ISS at the desired rendezvous altitude with Zvezda. As of midday today, the Station has circled the Earth more than 8,095 times since November 1998.

On May 22 mission specialists Jeff Williams and James carried out external maintenance work on the ISS.

On May 23 at 00:03 GMT the Atlantis crew opened the first hatch to PMA-2 and entered the Station. The crew replaced a set of batteries in Zarya, installed fans and ducting to improve airflow, and delivered supplies and equipment. Three hour-long orbit raising burns on May 24 and 25 by the RCS engines on Atlantis raised the station to a 372 x 380 km x 51.6 deg orbit.

The STS-101 crew left the station on May 26, closing the PMA-2 hatch at 08:08 GMT and undocking at 23:03 GMT. Atlantis performed a 180 degree flyaround of the station and departed the vicinity around 23:44 GMT.

Atlantis closed its payload bay doors around 02:30 GMT on May 29 and fired the OMS engines for deorbit at 05:12 GMT. The vehicle landed on RW15 at Kennedy Space Center at 06:20 GMT. Atlantis was to be turned around for the next ISS shuttle flight, STS-106.

Left in orbit was the renovated International Space Station, equipped with an upgraded electrical system, new fans, filters, fire extinguishers, smoke detectors and communications gear.

Commander Jim Halsell, Pilot Scott Horowitz and Mission Specialists Mary Ellen Weber, Jeff Williams, Jim Voss, Susan Helms and Yury Usachev will spend much of the day checking out orbiter systems and space walking equipment, while continuing to slowly close in on the station through a series of calculated rendezvous maneuvers.

The crew will examine and prepare the tools required to support rendezvous and docking operations as well as perform checks of the extravehicular mobility units, or space suits, that will be used by Williams and Voss during the planned space walk Sunday night into Monday morning. Both suits are checked far enough ahead of the space walk to ensure good working condition in plenty of time to allow for any required troubleshooting work by the specialists on the ground.

Also tonight and into tomorrow, Halsell will assist Weber in testing Atlantis' mechanical arm, checking its operation while conducting a video survey of the payload bay. This procedure will make certain the arm is functioning properly to support the space walk

Atlantis is currently in a highly elliptical orbit of 199 x 98 statute miles. At about 7 o'clock this evening, Central time, the shuttle was a little over 2,700 s.m. behind the station, closing in at a rate of about 546 s.m. every 90 minutes.

Riding aboard the upgraded and refurbished space Shuttle Atlantis, Commander Jim Halsell, Pilot Scott Horowitz and Mission Specialists Mary Ellen Weber, Jeff Williams, Jim Voss, Susan Helms and Yury Usachev rocketed away from their Florida launch site at 5:11 a.m. Central time, a pre-dawn launch by Shuttle standards. Atlantis quickly rose into daylight as it raced up the Eastern seaboard in pursuit of the 76-foot long, 35-ton international station, which was flying over the Ukraine, southwest of Kiev.

The launch was Atlantis' first since September 1997. Atlantis recently underwent major modifications, including the introduction of a state-of-the-art, hi-tech glass cockpit filled with computer displays to replace the old cockpit dials and switches.

Atlantis launched on time after three delays last month caused by high winds at the launch site and at overseas emergency landing strips. Today, conditions were perfect. Atlantis is scheduled to link up to the space station at 11:31 p.m. Central time Saturday night (12:31 a.m. Eastern time Sunday morning).

Once on orbit, Atlantis' crew began to set up shuttle systems for the planned 10-day mission, preparing to open the ship's cargo bay doors, which will be followed by the activation of the double Spacehab module housed in the rear of the cargo bay, containing more than a ton of supplies the crew will transfer to the station.

The astronauts will begin their first eight-hour sleep period just five hours after liftoff, at 10:11 a.m. Central time, and will be awakened at 6:11 p.m. this evening to begin their first full day in orbit. Prior to the start of that sleep period, Halsell and Horowitz will fire Atlantis' maneuvering jets in the first of a series of maneuvers designed to put the shuttle on a precise course to the International Space Station.

After the first rendezvous maneuver, Atlantis will be circling the Earth in a slightly elliptical orbit of about 201 by 124 statute miles, inclined 51.6 degrees to either side of the equator.

As of about 6:30 p.m. this evening, the Shuttle trailed the station by about 70 nautical miles and was closing in by about 14 nautical miles with each orbit of Earth. The final phase of rendezvous will begin when Atlantis reaches a point about eight nautical miles directly behind the station and fires its engines in a terminal phase initiation burn at 8:39 p.m. Central.

The TI burn, as it is called, will put the Shuttle on a course directly toward the station during the next orbit of Earth. As Atlantis moves within about a half-mile of the station, Halsell will take over manual control of the Shuttle's approach, flying the Shuttle from controls in the aft cockpit. Atlantis will arrive at a point about 600 feet directly below the station about 10:09 p.m. Central, and Halsell then will begin a half-circle of the orbiting outpost. Atlantis will pass about 350 feet in front of the station and then move to a point about 250 feet directly above it about 10:34 p.m. Central.

Halsell will then begin to descend toward the station and, at about 10:38 p.m. Central, hold position at a point about 170 feet away. Halsell will maintain that distance for about 20 minutes to allow the station to move within range of Russian ground communications stations before continuing the approach. At 11:20 p.m., Halsell will hold position again briefly at a point about 30 feet from the station to ensure the Shuttle and station docking mechanisms are precisely aligned. Docking is expected about 11 minutes later with the Shuttle contacting the station at a slow rate of about a tenth of a foot per second.

During the rendezvous, Pilot Scott Horowitz will assist Halsell in controlling Atlantis' approach. Mission Specialists Susan Helms and Yury Usachev also will assist with the rendezvous and docking, with Mary Ellen Weber and Jeff Williams operating the Shuttle's docking mechanism.

After docking, a hatch leak check will be performed and the astronauts will review plans for Sunday night's scheduled space walk by Williams and Jim Voss. Atlantis' crew will not open the hatch to the Unity module and enter the station until Monday evening, 24 hours after the space walk is completed.

Commander Jim Halsell and his crew have begun to open the various hatches between the two spacecraft in a process that will take about two hours to complete. A total of five different hatches will be opened during the crew's ingress into various parts of the station. The first hatch to be opened will be on Pressurized Mating Adapter-2 (PMA-2) which joins the Shuttle's docking mechanism to the Unity module. Next will be the hatch leading to the interior of the Unity node. Third in line will be the PMA-1 hatch at the opposite end of Unity. Next will be the hatch leading into the Zarya control module. The fifth and final hatch to be opened will be the instrumentation cargo compartment in the rear portion of Zarya.

The first two individuals to enter the station will be Mission Specialists Yury Usachev and Susan Helms, who will be getting a sneak preview of their future orbiting home. Usachev, Helms and fellow STS-101 crewmember Jim Voss will become the second expedition crew to inhabit the station.

The first actions by the crew upon entering the station will be to collect air quality samples in Unity and Zarya for comparison with a sample from Atlantis. They also will measure air-circulation velocity and monitor carbon dioxide levels. Upon completion of those tasks, the crew members will break out their tools and rework some of the air ducts in Zarya to improve airflow. They will re-route some ducts, strengthen others, add new acoustic mufflers where required, and they'll swap out the contaminant filter in Zarya and the charcoal filter in Unity.

Once they determine that there has been a sufficient improvement in air circulation, the crew members will turn their attention to maintenance issues and cargo transfers. The main task for this evening will be the replacement of two of the batteries on the station. Problems with performance of at least two of Zarya's six "800A" storage batteries led to a decision to replace four batteries during STS-101 docked operations. The third battery will be replaced tomorrow and the fourth on Wednesday.

Atlantis' crew will replace the four suspect, 163-pound batteries -Numbers 1, 2, 3 and 5 - as well as three of their 34-pound current converters and two of their 10-pound current converter controllers. The batteries on the station collect energy during the daytime portion of the Station's orbit and provide power at night.

The replacement of the station batteries is a well choreographed procedure that has been refined during pre-flight training activities in NASA and Russia training facilities. Of the six batteries onboard the station, a minimum of four batteries will always remain online and available to support station systems.

In addition to replacing the batteries on the station, other maintenance activities planned during docked operations include replacing three fire extinguishers that have reached the end of their design life, 10 smoke detectors and four cooling fans.

The Atlantis and the station both continue to operate well with flight controllers reporting no problems of significance for any of the mission's activities. The shuttle and station are docked in an orbit with a high point of 209 statute miles and a low point of 203 statute miles, circling Earth every 91 minutes.

Voss and Williams started the spacewalk early and remained ahead of schedule throughout. The astronauts secured a United States-built crane that was installed on the station last year; installed the final parts of a Russian-built crane on the station; replaced a faulty antenna for one of the station's communications systems; and installed several handrails and a camera cable on the station's exterior. The six-hour, 44-minute spacewalk began at 8:48 p.m. CDT Sunday and was completed at 3:32 a.m. CDT today. Assisting with the activities from inside Atlantis' cabin was Pilot Scott Horowitz while Mission Specialist Mary Ellen Weber operated the Shuttle's robotic arm, which she used to maneuver Voss during much of the spacewalk.

The extravehicular activity conducted by Voss and Williams marks the fifth spacewalk conducted for construction of the International Space Station; the 49th spacewalk based out of the Space Shuttle; and the 85th spacewalk in history conducted by U.S. astronauts.

The crew's attention now turns to entering the station, a process planned to begin at 7:11 p.m. today. The astronauts will open a total of six hatches as they move through the station's compartments. The first hatch into the station's Unity connecting module will be opened about 7:56 p.m. and the first hatch into the Zarya module will be opened about 9:11 p.m. Once inside the station, the crew will begin transferring equipment and performing maintenance work immediately. Replacement of four batteries in the Zarya will begin about 11:31 p.m., with astronaut Susan Helms and cosmonaut Yury Usachev scheduled to install two new batteries and their associated electronics. Helms and Usachev will install the remaining two replacement batteries later during the docked phase of the flight.

The crew plans to go to sleep at about 8 this morning and will be awakened by Mission Control at 3:56 p.m., with the focus of work this evening being the first entry into the station. Atlantis and the International Space Station remain in good condition orbiting Earth each 91 minutes with a high point of 209 statute miles and a low point of 203 statute miles.

Astronaut Susan Helms and Cosmonaut Yury Usachev were the first crew members to enter the station as they opened the first of five station hatches at 7:03 p.m. CDT Monday. Helms and Usachev then opened the hatch into the station's Unity connecting module a half-hour later and were quickly joined by Astronaut Jim Voss. Voss, Helms and Usachev are scheduled to live aboard the station for more than four months next year as the second resident station crew. Helms and Usachev next entered the Zarya module at 7:53 p.m. CDT and opened the final station hatch, accessing Zarya's main compartment, at 7:58 p.m. The crew went to work in the modules immediately, placing ducting throughout the station to improve air circulation and prevent problems with stale air that were experienced during a mission last year. Because of problems reported by the crew of that previous mission, STS-96 in May 1999, the ducting was modified for this flight and Atlantis' crew has reported no problems with air circulation.

Maintaining a pace hours ahead of schedule, Helms and Usachev replaced two of six batteries in the Zarya module along with some associated battery-charging electronics. Two additional fresh batteries will be installed on successive days of the mission. This morning, station controllers in Moscow have begun charging the first of the two newly installed batteries, finding it functioning perfectly thus far. The crew also installed three fresh fire extinguishers in Zarya, replacing three that were nearing the end of their design life. Inside the Unity module, Pilot Scott Horowitz and Mission Specialist Jim Voss replaced a power distribution box for a United States-built communications system. The crew also inspected the station for signs of condensation or mold, finding all areas clean and dry.

Aboard Atlantis, Mission Specialist Mary Ellen Weber readied more than a ton of supplies -- ranging from sewing kits and trash bags to an exercise treadmill and IMAX film camera -- for transfer to the station beginning this evening. The crew also began filling several water containers that will be left aboard the station as well to await future resident station astronauts.

The crew will begin a sleep period at 7:41 a.m. CDT and awaken for Day 6 of the mission at 3:41 p.m. CDT. This evening, Commander Jim Halsell will fire Atlantis' steering jets 27 times over an hour to boost the average altitude of the station by about nine statute miles. A similar process will be repeated twice more later in the mission to increase the station's average altitude by a total of about 27 statute miles before Atlantis departs. The higher altitude will aim the International Space Station toward the optimum orbit for a link up with the Russian Zvezda living quarters module planned for launch in July.

The Atlantis and station complex are now in an orbit with a high point of 208 statute miles and a low point of 204 statute miles, circling Earth each 91 minutes.

Halsell along with Pilot Scott Horowitz and Mission Specialists Mary Ellen Weber, Jeff Williams, Susan Helms, Jim Voss and Yury Usachev will spend their second day inside the station as they continue the maintenance work and supply transfer activities that began yesterday. During their first day, Atlantis' crew moved 870 pounds of supplies and equipment inside the station. That material along with the 326 pounds of equipment attached to the exterior of the station by Williams and Voss during their space walk means almost 1,200 pounds of gear already have been transferred to the station. A total of 3,381 pounds of equipment and provisions will be transferred to the station before Atlantis undocks.

Maintenance work on Flight Day Six will include the third of four planned replacements of station batteries. Helms and Usachev will repeat the procedures they followed yesterday when the first two batteries were replaced. One of the batteries replaced yesterday already has been recharged and been pronounced in excellent condition. The second replacement battery will go through its charging and checkout shortly. All of the battery replacement work is carefully designed so that at least four batteries are always online and available to support station operations.

Other maintenance work on schedule today includes the installation of new smoke detectors, and replacement of fire extinguishers that are nearing the end of their design life.

The first of three planned station reboost maneuvers is scheduled to take place tonight at 7:01 p.m. CDT. The maneuver will see Atlantis' steering jets fire 27 times over a 58 minute period to boost the average altitude of the station by about nine statute miles. A similar process will be repeated tomorrow and again on Thursday to increase the station's average altitude by a total of about 27 statute miles before Atlantis departs. The higher altitude will aim the International Space Station toward the optimum orbit for a link up with the Russian Zvezda living quarters module planned for launch in July.

Late this evening, Halsell, Williams and Voss will take a few minutes to conduct a trio of interviews with reporters from the Cable News Network, Armed Forces Television and Space.Com. The interviews are scheduled to begin at 11:41 p.m. CDT.

The Atlantis and station complex continues to operate in fine fashion orbiting the Earth once every 91 minutes.

Commander Jim Halsell and pilot Scott Horowitz fired Atlantis' steering jets 27 times during almost an hour Tuesday evening to gently lift the 35-ton outpost about 10 miles higher. The same process will be repeated again tonight and on Thursday to boost the station by about 27 miles in total and leave it in an orbit with an average height of about 233 miles when Atlantis departs on Friday.

As has been the case through much of the mission, the crew completed most jobs ahead of schedule. Inside the Zarya module, Astronaut Susan Helms and Cosmonaut Yury Usachev completed the installation of a third fresh battery for the station. A fourth battery will be installed tonight. Meanwhile, station controllers in Moscow completed charging the first of two batteries installed in Zarya yesterday, and it is now operating perfectly. Controllers are charging the second new battery installed in the station, although the charging of that battery was interrupted briefly early this morning by an unforeseen conflict that prevents conducting charging and battery installation work simultaneously. The interruption halted the battery charging for about an hour and a half, but the process is now again under way with no problems. Controllers are confident the new battery is in good condition and are revising plans to ensure no similar conflict occurs as the crew is installing the final new battery tonight.

The crew also installed 10 new smoke detectors in Zarya, replacing detectors that had reached the end of the lifetime for which they were designed to operate. The astronauts replaced four cooling fans in Zarya for the same reason. In addition, they completed the installation of new cabling for the module's central computer that will allow that computer to be turned on and off via a United States-built backup station communications system. As the installation work progressed, the crew continued transferring items ranging from exercise equipment to computer printers to the station for use by future crews. Well over 1,200 pounds of gear have been moved from Atlantis to the station thus far.

Tonight, Helms and Usachev will install the final new battery in the station. Later, Halsell and Horowitz will fire Atlantis' jets to perform the second part of the three-part station reboost. Then the crew's attention will turn to unloading various supplies from Atlantis and stowing them aboard the station. The crew will take a short break from their work at 10:21 p.m. CDT for an interview with ABC radio news; KOIN-TV of Portland, OR; and a Department of Housing and Urban Development educational group.

Atlantis and the International Space Station are in an orbit with a high point of 219 miles and a low point of 212 miles, circling Earth every 91 minutes.

Halsell, Horowitz and Mission Specialists Mary Ellen Weber, Jeff Williams, Susan Helms, Jim Voss and Yury Usachev will spend their third day inside the station continuing the maintenance work and supply transfer activities that began Monday evening. During their first two days inside the station, the astronauts have moved more than a ton (2,049 pounds) of supplies and equipment inside the facility to be used by the first station crew. More than 3,000 pounds will be transferred to the station before Atlantis undocks on Friday evening.

Helms and Usachev already have completed the replacement of the fourth and final battery. The second battery replaced on Monday evening is fully recharged and working well as it supports station operations. The third battery, which was replaced last night, has begun its 20-hour charging process. All of the battery work is designed so that at least four of the station's six batteries are available to support station systems.

Other work on tap for this evening includes the replacement of a Zarya radio telemetry system which has reached the end of its design life. The radio telemetry system collects and stores station data when ground station communications are not available. The crew also will fill four large water bags and transfer the bags to the station to join seven similar bags left during the STS-96 mission last year. The water bags will be part of the potable water supply used by the first station crew when it arrives later this year.

Tonight also will see the second of three planned reboost maneuvers to raise the station's altitude. The one-hour procedure will involve 27 pulse firings of Atlantis's maneuvering thrusters. The three reboosts will raise the station to a new altitude about 237.5 x 227 statue miles and will place the station in the optimum altitude for the arrival of the Zvezda Service Module when it is launched in July.

Shuttle and station managers have decided to move the undocking time to one orbit later. The new undocking time is now 6:07 p.m. CDT on Friday, May 26th and will happen while the two spacecraft are over Russian ground stations. The later undocking will allow the crew to get a full eight-hour sleep period. Atlantis will make shortened fly around, one half revolution of the station, before leaving the vicinity of the station. The later undocking will have no impact to Atlantis' landing at Kennedy Space Center which still is planned for 1:18 a.m. CDT Monday, May 29th.

Later this evening at 10:11 p.m. CDT, Halsell, Horowitz and Helms will participate in a trio of interviews with the ABC Radio Network, KOIN-TV in Portland, Oregon, and a webcast education event for the Housing and Urban Development agency.

The Atlantis and station complex continues to operate well, completing one orbit of the Earth every 91 minutes.

The main task of the day will be completing the transfer of gear and supplies to the station. In the first three days of transfer activities, the crew has moved more than 3,000 pounds of material onto the station.

The third and final reboost maneuver began a few minutes ago at 6:36 p.m. CDT. Like the two previous reboosts, Atlantis' reaction control system jets will be fired 27 times over a 58 minute period to gently raise the station. At the end of tonight's reboost, it is expected that the station's average altitude will have been raised by 27 statue miles.

The astronauts have completed all battery work on the station. The third battery that was replaced has completed its recharging and testing and has been put back online supporting station operations. The fourth and final new battery will begin its recharge later this evening and will be back online before Atlantis undocks tomorrow evening.

Shortly before they begin exiting the station for the final time, Halsell, Horowitz and Weber will take a few minutes to conduct a trio of interviews with three news organizations -- CBS Newspath, Fox News Network and KTBS-TV in Shreveport, LA -- starting at 9:11 p.m. CDT.

Just before 11:30 p.m., Halsell and his crew will reverse the steps they used when they entered the station Monday evening, closing each of the five hatches associated with station components or transfer tunnels. The overall process of closing out the station and preparing for undocking is expected to take about two hours to complete.

Everything remains on schedule for undocking on Friday evening at 6:07 p.m. CDT. Atlantis will perform a one half revolution of the station, before the final separation burn is initiated. Atlantis remains on track for a landing back at Kennedy Space Center at 1:18 a.m. CDT on Monday, May 29th.

Late Wednesday, Astronauts Susan Helms and Jim Voss along with Cosmonaut Yury Usachev completed the installation of a fourth and final fresh battery in the station. Station flight controllers in Russia have completed charging two of the newly installed batteries and they are operating perfectly. The third new battery is currently undergoing a 20-hour charging process, although controllers did note some apparently irregular readings in data during the early portions of the charging activity. However, after further analysis, controllers now believe the irregular information was likely a ground communications problem and that the battery is in excellent condition. Charging of the fourth new battery will begin later today and be completed before Atlantis undocks from the station on Friday.

Later, Voss and Williams installed several new storage compartments behind panels in the Zarya module. Helms and Usachev also installed a new Radio Telemetry System in the module, a memory unit that can store data onboard when the station is not in communications with the ground. The new memory unit replaces one that was nearing the end of its planned operational lifetime.

Commander Jim Halsell and Pilot Scott Horowitz fired Atlantis' steering jets to perform the second part of a three-day maneuver that is raising the station's orbit. Atlantis' jets were fired 27 times over the course of almost an hour to raise the Atlantis-station complex's average altitude by about nine miles. The third and final orbit-raising activity is planned tonight and will leave the station about 27 miles higher than when Atlantis arrived, in an optimum orbit to await the launch of a station living quarters module by Russia in July.

The crew has transferred more than a ton of gear -- ranging from sewing kits to clothing -- to the station to await use by the first resident crew. Among the items transferred this morning were a stationary bicycle ergometer as well as four 12-gallon bags of drinking water. Tonight, the crew will wrap up the transfer of equipment to the station with plans in place to unload a total of more than 3,000 pounds of gear by the time Atlantis leaves. Halsell, Horowitz and Mary Ellen Weber will take a brief break from their activities at 9:11 p.m. CDT for an interview by CBS News, Fox News and KTBS-TV of Shreveport, LA.

The crew will begin a sleep period at 7:11 a.m. CDT and awaken at 3:11 p.m. to begin the eighth day of the mission. Atlantis is scheduled to undock from the station at 6:07 p.m. CDT Friday and land at the Kennedy Space Center, Florida, at 1:18 a.m. CDT Monday.

The Atlantis-International Space Station complex is now in an orbit with an altitude of about 225 miles, circling Earth every 91 minutes.

Undocking occurred at 6:03 p.m. Central time, as Pilot Scott Horowitz slowly backed Atlantis away from the space station and then flew a half-circle around the station, before firing Atlantis' jets in a final separation burn at 6:41 p.m. Atlantis' crew leaves behind a refurbished and rejuvenated space station with four new batteries, 10 new smoke detectors, and four new cooling fans in the Zarya module, a revamped communications system in the Unity module and 1 ½ tons of other supplies, including clothing and water.

Now flying solo, the seven-member Atlantis crew will enjoy several hours of off-duty time tonight in recognition of the ambitious pace of work they maintained throughout this flight. Commander Jim Halsell, Horowitz, and Mission Specialists Jeff Williams, Mary Ellen Weber, Jim Voss, Susan Helms and Yury Usachev will power down some of the equipment used during today's undocking and flyaround, and then will perform some routine housekeeping tasks before beginning their scheduled off duty time.

Toward the end of the crew's day, Usachev will take some time to talk with Russian media gathered at the Russian Mission Control Center just outside of Moscow in an event scheduled at 4:26 a.m. Central time Saturday morning. Usachev, along with crewmates Voss and Helms, will visit the station again next year to spend more than four months on board as the second resident crew scheduled to live on board.

The station is now in the optimum orbit to await the arrival of the next major station component -- a Russian-built living quarters that will launch in July -- flying in an orbit with a high point of 238 miles and a low point of 230 miles, circling the Earth every 92 minutes.

"I couldn't be happier with the way this mission has gone," Lead Flight Director Phil Engelauf said. "Our accomplishments are at more than 100 percent for the flight."

"The crew will be leaving a pristine International Space Station behind them," added Paul Hill, Lead Station Flight Director.

Highlights of the crew's work aboard the station included the installation of four new batteries and associated electronics; 10 new smoke detectors in the Zarya module; four new cooling fans; additional cables for the Zarya computer to enhance its capabilities; a new communications memory unit; and a new power distribution box for the United States-built backup communications system. A new communications antenna, the final parts of a Russian crane, and various cabling and handholds were installed on the station's exterior by Astronauts Jeff Williams and Jim Voss during a six-hour, 44-minute spacewalk. All of the new equipment has been checked out and is in excellent condition.

The crew unloaded over 3,300 pounds of gear from Atlantis. Subtracting equipment removed from the station and stowed on Atlantis, the net change in mass for the station is about one additional ton. Along with the new electrical equipment installed, the crew also stowed supplies for future crews aboard the station, including about 48 gallons of water in four 12-gallon bags; a treadmill, exercise bicycle ergometer, and resistive exercise device; and sewing kits, trash bags, clothes, tools, books, note pads and can openers, among other items. Overseeing the unloading and stowing of supplies was Astronaut Mary Ellen Weber. Also, Commander Jim Halsell and Pilot Scott Horowitz fired Atlantis' steering jets in gentle, hour-long maneuvers during each of the past three days to raise the station's orbital altitude by 27 miles. The station is now in the optimum orbit to await the arrival of the next major station component -- a Russian-built living quarters that will launch in July.

Astronaut Susan Helms and Cosmonaut Yury Usachev began backing out of the station -- closing five hatches behind them -- by closing a hatch to the Zarya module's main compartment at 12:23 a.m. CDT. The final hatch to the station was shut at 3:04 a.m. CDT as the orbiting complex flew about 234 miles above the Red Sea. Helms, Usachev and Voss will again visit the station next year to spend more than four months as the second crew to live aboard. In total, the astronauts on Atlantis spent three days, eight hours and one minute with the hatches open to the station during the mission.

Atlantis' undocking from the International Space Station is planned for 6:03 p.m. CDT, followed by a half-loop flyaround of the station - from above to underneath - before firing its jets for the final separation. Atlantis and the station are in an orbit with a high point of 238 miles and a low point of 230 miles, circling Earth every 92 minutes.

Shortly after 7 p.m. today, Commander Jim Halsell, Pilot Scott Horowitz and Flight Engineer Jeff Williams successfully test fired Atlantis' steering jets and verified the performance of the various aerosurfaces that will be used during Atlantis' high-speed return to Earth. This checkout of Atlantis' flight control surfaces and systems is a routine activity on the day prior to landing to verify that all required systems are operating as expected. The tests were monitored by Entry flight director John Shannon from Mission Control in Houston.

As Halsell, Horowitz and Williams conducted their work from the flight deck, crewmates Mary Ellen Weber, Jim Voss, Susan Helms and Yury Usachev continued stowing away equipment used over the past nine days on orbit. Throughout the five days of docked operations with the International Space Station, the Spacehab module in Atlantis' payload bay served as a way station for more than 3,000 pounds of material transferred between the two vehicles. As the astronauts prepare for their Memorial Day landing, they will ensure that equipment housed in that module -- and in Atlantis' crew cabin -- is properly stowed and secured in place.

Midway through the crew day -- about 11 p.m. -- the astronauts will gather for a final review of entry and landing procedures, and then will continue their stowage activities. Williams and Voss, who conducted a 6 1/2 hour space walk earlier in the mission, also will pack up and stow away their spacesuits and associated hardware.

The crew will take time from tonight's entry preparations to talk with reporters located at the Johnson Space Center in Texas, the Kennedy Space Center in Florida and the Russian Mission Control Center outside of Moscow in an interview scheduled to begin at 10:41 p.m.

Preliminary weather forecasts for Monday morning's landing indicate a slight possibility of rain within 30 miles of the landing site, and cross winds in excess of acceptable limits. The weather forecasts will be refined over the course of the next 24 hours in preparation for landing. For a 1:20 a.m. Central time landing at KSC, Atlantis' orbital maneuvering system engines would be fired in a deorbit burn at 12:13 a.m. In the event weather precludes a landing on the first opportunity, a second opportunity exists for a landing in Florida on the next orbit, with a deorbit burn at 1:50 a.m. resulting in a 2:56 a.m. landing.

Commander Jim Halsell flew Atlantis to a nighttime touchdown at the Florida spaceport at 1:20 a.m. Central time to complete a 4,076,000 mile mission, the second Shuttle flight of the year. It was the 14th nighttime landing in Shuttle history and the 22nd consecutive mission to end with a landing at KSC. Halsell was joined on Atlantis' flight deck by Pilot Scott Horowitz, Flight Engineer Jeff Williams and Mission Specialist Mary Ellen Weber. Crewmates Susan Helms, Jim Voss and Yury Usachev were seated down on the orbiter's middeck for entry and landing.

Atlantis returned to Earth after Flight Director John Shannon determined that crosswinds at the Kennedy Space Center's three-mile long landing strip were gentle and steady, enabling him to give the astronauts the green light to come home on time. Halsell fired the Shuttle's braking rockets at 12:12 a.m. Central time, allowing Atlantis to drop out of orbit for its high-speed descent. Atlantis passed over southern Mexico and the Gulf of Mexico before crossing over the Sarasota / Ft. Myers area of Florida en route to the Cape. Atlantis broke the quiet of the pre-dawn hours in Central Florida with a double sonic boom just minutes before touchdown, heralding its arrival at the landing site as it went subsonic.

Left in orbit is the renovated International Space Station, equipped with an upgraded electrical system, new fans, filters, fire extinguishers, smoke detectors and communications gear. ISS flight controllers report that the complex is functioning in excellent condition. The Station is orbiting at an altitude of about 238 statute miles, awaiting the arrival of its next component, the Russian Service Module "Zvezda", which is scheduled to be launched on a modified Proton rocket from the Baikonur Cosmodrome in Kazakhstan in July. The ISS will automatically rendezvous and dock with "Zvezda" about two weeks after the new module is placed in orbit.

Atlantis will now be processed for the next Shuttle flight in early September to return to the International Space Station with another crew for the outfitting and supply of the newly arrived Service Module. That flight, STS-106, will be led by veteran Commander Terry Wilcutt.

The STS-101 astronauts will spend Memorial Day relaxing with their families in Florida before returning to Houston Tuesday afternoon at around 1:30 p.m. Central time for a welcoming ceremony at Ellington Field near the Johnson Space Center. JSC employees and families are invited to attend the ceremony.

With Expedition One Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev looking on from inside the Zvezda living quarters, the Progress automatically linked up to Zvezda's aft docking port at 3:50 a.m. Central time as the Station sailed over Central Asia. Unlike the docking of the last Progress to the Station in November, which had to be conducted manually after the automated docking system experienced a problem, today's linkup was textbook and uneventful. Last Saturday, with Gidzenko at the controls, the crew undocked its Soyuz capsule from the same docking port and flew to a redocking at the nadir docking port of the Zarya module to make room for the Progress.

Within two hours of docking, the crew opened hatches between Zvezda and Progress and began to unload its supplies, which include clothing, spare parts, computers and office gear for Shepherd, Gidzenko and Krikalev and their replacements, Expedition Two Commander Yury Usachev, Jim Voss and Susan Helms, who are set to be launched next Thursday aboard the Shuttle Discovery to begin the second expeditionary mission to the Station. The Expedition One crew will return home aboard Discovery on March 20 to complete more than four months in orbit.

Late yesterday, NASA managers officially set March 8 for the launch of Discovery to the Station on the STS-102 mission to not only transport the second Expedition crew, but to continue the outfitting of the U.S. Laboratory Destiny through two space walks and the delivery of additional logistical items, spare parts and hardware in an Italian-built cargo module called Leonardo. The first racks of science equipment for research aboard the Station will also be moved from Leonardo into Destiny, including the Human Research Facility, which will be a mainstay for experiments involving the study of the reaction of the human body to weightlessness.

The International Space Station continues to orbit the Earth in excellent shape at an altitude of 235 statute miles.

Discovery was launched on mission STS-102 (Space Station flight 5A.1) into an initial 60 x 222 km x 51.6 deg orbit. The mission was delivery of supplies and equipment, and changeout of the Expedition One and Expedition Two station crews. STS-102 carried the Leonardo Multi Purpose Logistics Module (MPLM), built by Alenia Spazio (Torino), to the International Space Station. The 6.4 m x 4.6 m cylindrical MPLM was a descendant of the Spacelab long modules. Also carried was a Spacehab/Energia unpressurized Integrated Cargo Carrier with LCA/MTSAS-A, RU, and PFCS. A sidewall adapter beam with two GAS canisters (G-783 and WSVFM) was also on board. WSVFM measured vibration during launch. Another adapter beam, probably at the rear of the payload bay, carried SEM-9. SEM-9 and G-783 contained high school microgravity experiments.

Leonardo carried 16 'racks' of equipment, including the Human Research Facility Rack (Rack 13) which allowed the astronauts to do extensive medical experiments, the CHeCS Rack (28), the DDCU-1 and DDCU-2 racks (7 and 9), the Avionics-3 (Rack 6), and the MSS Avionics/Lab (Rack 11) and Avionics/Cupola (Rack 12) racks for a total of 7 equipment racks to be installed on Destiny. Three Resupply Stowage Racks (50, 51, 52) and four Resupply Stowage Platforms (180, 181, 182 and 188) remained installed on Leonardo, with their equipment bags being individually transferred to the Station. System Racks 2, 3, 4, 5 and 8 were already on Destiny together with stowage racks 110 through 117. Each rack had a mass of 150-300 kg.

The orbiter fired its OMS engines at 1221 GMT to raise the orbit to 185 x 219 km. Discovery docked with the PMA-2 port on the Station at 0639 GMT on March 10. The LCA (Lab Cradle Assembly) was attached to Destiny's +Z side during an EVA. It was to be used on the next mission to temporarily place a Spacelab pallet on Destiny during installation of the Station's robot arm. Later, it would be the site for the main Station truss, beginning with segment S0.

The PMA-3, on Unity at the -Z nadir position, had to be moved to the port position to make room for Leonardo. An external stowage platform was attached to Destiny and the External Stowage Platform and the PFCS Pump Flow Control System were added to the port aft trunnion on Destiny. A rigid umbilical (RU) was connected to the PDGF grapple fixture on Destiny to support the Station's future robot arm. Leonardo was docked to Unity at -Z for a while so that its cargo could be transferred to the station easily; it was then be returned to the payload bay and brought back to earth.

At 0232 GMT on March 19 command of ISS was transferred to Expedition 2 and the hatches were closed. Discovery undocked at 0432 GMT and flew once around the station before departing at 0548 GMT. ISS mass after undocking was 115527 kg. The OMS engines fired for the deorbit burn at 0625 GMT on March 21, and Discovery touched down on runway 15 at Kennedy Space Center at 0731 GMT.

Commander Jim Wetherbee, Pilot Jim Kelly and Mission Specialists Andy Thomas, Paul Richards, Yury Usachev, Jim Voss and Susan Helms rocketed away from Launch Pad 39-B at 5:42 a.m. Central time, lighting up the crystal clear central Florida skies as they began their pursuit of the international complex. Usachev, Voss and Helms, who make up the second Expeditionary crew to the ISS, will replace Expedition One Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev, who were in their 128th day in space and their 126th day aboard the Station as Discovery began its pursuit.

At the time of launch, the three Expedition One crewmembers aboard the ISS were passing over the south Pacific, about 1000 statute miles south of Perth, Australia. Shortly after Discovery reached orbit, a videotape of the Shuttle launch was uplinked to the Station crew on a laptop computer onboard.

Less than nine minutes after liftoff, Discovery's astronauts settled into orbit and went to work to prepare the Shuttle's systems for their planned 12-day mission. The first major task on the flight plan was to open Discovery's cargo bay doors prior to receiving a "go" for orbital operations from Ascent Flight Director Wayne Hale. The astronauts are expected to set up computers and flight deck gear before beginning an eight-hour sleep period at 10:42 a.m. Central time. The Shuttle crew will be awakened at 6:42 p.m. Thursday to begin its first full day in space.

With this morning's successful launch behind them, Discovery's astronauts will turn their attention to their chase of the International Space Station, performing several firings of the ship's jet thrusters over the next 40 hours to set up a docking with the outpost on Friday night just before midnight Central time. Over the ensuing week, the crew will perform two space walks outside the ISS as they help to outfit the recently installed Destiny research laboratory. The Leonardo Multi-Purpose Logistics Module, built by the Italian Space Agency, will be attached to the ISS early next week, loaded with almost five tons of equipment, and systems and science racks for transfer to Destiny.

The Expedition crews will exchange places on the ISS in a three-step fashion, beginning with Usachev and Gidzenko swapping roles as Station and Shuttle crewmembers early Saturday within hours after docking.

Discovery is circling the Earth in excellent shape as it flies in an orbit inclined 51.6 degrees to either side of the Equator. The International Space Station continues to sail around the Earth with no significant systems issues being tracked by ISS flight controllers.

In preparation for that rendezvous and docking, Discovery's crew was awakened at 6:42 p.m. Thursday to begin its first full day on orbit. The wakeup song from Mission Control was "Living The Life" by the Rockit Scientists, a group of training division instructors with whom shuttle Commander Jim Wetherbee plays drums from time to time.

After wakeup, the crew of four shuttle and three station expedition crewmembers got busy checking out systems and equipment to assist with mission objectives, including the robotic arm, the two spacesuits that will be worn for the first Extravehicular Activity (EVA), and the rendezvous tools to assist with the final hours of Discovery's approach and docking to the station.

The STS-102 crew is made up of Wetherbee, Pilot Jim Kelly, Flight Engineer Paul Richards and Mission Specialist Andy Thomas. The Expedition Two crew consists of Russian Commander Yury Usachev, and Flight Engineers Jim Voss and Susan Helms.

Usachev, Voss and Helms, will replace Expedition One Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev, who shortly will wrap up a 4-½ month stay aboard the station and return home aboard Discovery.

With a docking test behind it, the Expedition One crew turns its attention to final stowage in preparation for Discovery's arrival.

After Friday's late night docking, the astronauts will perform two space walks outside the ISS to continue the process of outfitting the Destiny research laboratory. The Leonardo Multi-Purpose Logistics Module, built by the Italian Space Agency, will be attached to the ISS late Sunday. It is filled with nearly five tons of equipment, including systems and science racks that will be transferred to Destiny.

The Expedition crews will exchange places on the ISS in a three-step fashion, beginning with Usachev and Gidzenko, who will swap places as Station and Shuttle crewmembers early Saturday within hours after docking.

As of 7:30 p.m. Thursday, Discovery trailed the station by about 7,000 miles, closing that distance at a rate of 700 miles each orbit of the Earth, or every 90 minutes. Simultaneously, the ISS is in good shape and ready to support the shuttle's arrival Friday.

The shuttle crew was awakened with the Russian song "Vashe Blagorodiye," a song from a movie entitled "White Sun of the Desert" that is traditionally watched by cosmonauts the night before a launch from the Baikonur Cosmodrome in Kazakhstan. The song was played for Expedition Two Commander Yury Usachev, who is spending his last day aboard Discovery before beginning a handover of station command with Expedition One crewmember Yuri Gidzenko.

All activities are on track for a docking of Discovery to the station at 11:34 p.m. The final phase of Discovery's rendezvous with the station was to begin with a Terminal Initiation (TI) engine firing by the shuttle at 9:13 p.m. with Discovery about 50,000 feet behind the station. The TI burn puts the shuttle on course to intercept the station during the next orbit of Earth. At about 10:30 p.m., as Discovery reaches a point about a half-mile below the complex, Commander Jim Wetherbee will take over manual control of the approach. Wetherbee will fly Discovery to a position about 300 feet in front of the station, then move in toward a docking port attached to the end of the station's Destiny Laboratory.

During the docking, Pilot Jim Kelly will help control Discovery's approach as astronauts Andy Thomas and Paul Richards manage the shuttle's docking mechanism and rendezvous tools. Using a view from a camera mounted in the center of Discovery's docking mechanism, Wetherbee will center the docking ports of the two spacecraft precisely, double-checking the alignment 30 feet out. The final approach will be at a relative velocity of one-tenth of a foot per second.

When Discovery makes contact with the station's docking port on Destiny, latches will automatically connect the two spacecraft as they fly high off the east coast of Brazil. Once relative motion between the spacecraft stops, Thomas will retract the docking ring on Discovery's mechanism, closing latches to firmly secure the shuttle to the station. The hatches between the shuttle and station are to be opened about two hours later at 1:42 a.m. Saturday.

The crew will begin transferring crews, equipment and supplies immediately. The first crew exchange is planned to allow Usachev to be aboard the station jointly with Expedition One Commander Bill Shepherd for as long as possible to facilitate the change of leadership. The hatches will be closed again at 4:37 a.m. Saturday so the shuttle crew can prepare for the first of two planned spacewalks, a sojourn by astronauts Jim Voss and Susan Helms set to begin Saturday evening.

The stage is set for the eighth shuttle docking to the ISS with both spacecraft in good shape.

Overnight, the STS-102 astronauts Jim Wetherbee, Jim Kelly, Paul Richards and Andy Thomas, and Expedition 2 crew members Yury Usachev, Jim Voss and Susan Helms installed and checked out a targeting camera, extended the orbiter docking system's spring-loaded docking ring and unpacked rendezvous tools such as laptop computers and hand-held range-finders. They are scheduled to begin an abbreviated seven-hour sleep period at 9:42 a.m. today. When the crew wakes up at 4:42 p.m. to begin their final rendezvous activities, Discovery will be about 40 miles behind and slightly below the ISS.

About 9:15 p.m., at a distance of about nine miles behind the station, Wetherbee will fire Discovery's engines in a Terminal Initiation (Ti) burn, allowing the shuttle to close in, using its rendezvous radar system to track distance and approach speed. Once Discovery is about half a mile below the station, Wetherbee will take over manual control. Wetherbee will fly Discovery slowly to a point about 600 feet directly below the station, then move up and in front of the orbiting outpost. Closing in and stopping a little more than 300 feet directly in front of the station, Kelly will help control Discovery's approach as Thomas and Richards manage the shuttle's docking mechanism and rendezvous tools. Using a view from a camera mounted in the center of Discovery's docking mechanism, Wetherbee will center the docking ports of the two spacecraft precisely, double-checking the alignment 30 feet out. The final approach will be at a relative velocity of one-tenth of a foot per second.

When Discovery makes contact with Pressurized Mating Adapter 2 on the end of the Destiny module, latches will automatically attach the two spacecraft together. Once relative motion between the spacecraft stops, Thomas will retract the docking ring on Discovery's mechanism, closing latches to firmly secure the shuttle to the station

Early this morning, Wetherbee and Usachev received a congratulatory call from Sergio De Julio, president of the Italian Space Agency responsible for developing the Multi-Purpose Logistics Module, Leonardo, that holds nearly five tons of equipment to be transferred to the station. Leonardo will be temporarily attached to the station during the first of two scheduled space walks on Saturday, to allow the transfer of the equipment and supplies housed inside.

Meanwhile, on board the ISS, Expedition 1 Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev made last-minute preparations for the arrival of their temporary guests and long-term replacements. The Expedition crews will exchange places on the ISS in a three-step fashion, beginning with Usachev and Gidzenko, who will swap places as Station and Shuttle crew members early Saturday within hours after docking.

"You have a great looking ship there, Captain Shepherd," Wetherbee radioed to the station.

The linkup, which occurred as the two spacecraft were flying above the southern Pacific Ocean, just east of New Zealand, was delayed by about an hour when one of the station's P-6 solar arrays failed to register as being properly feathered to avoid damage from the shuttle steering jet plumes. Wetherbee hovered 400 feet away from the Pressurized Mating Adapter-2 port as he awaited the array latch verification and proper lighting conditions for his final approach.

Station flight controllers and crew members also teamed up to overcome a shuttle communications problem that occurred just after docking. Downlinked signals could not be relayed from the White Sands Ground Station in New Mexico to Houston for about 34 minutes, but messages were passed on to the shuttle crew via the space station control room and a radio link between the station and shuttle.

After hooks and latches created a secure bond, the hatches between the two spacecraft were opened at 2:51 a.m. CST, beginning eight days of docked operations. The eighth shuttle mission to the station will feature the first crew exchange aboard the multinational orbiting outpost and the delivery of the first research experiment package for the Destiny laboratory module.

Expedition Two Commander Yury Usachev was the first to join Expedition One Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev aboard the station. He was followed closely by Wetherbee, Expedition Two Flight Engineers Jim Voss and Susan Helms, and visiting shuttle astronauts Jim Kelly, Andy Thomas and Paul Richards. All 10 crew members spent several minutes greeting each other in the spacious Destiny module.

The arrival of Discovery signaled the beginning of the end of the Expedition One crew's four and a half month stay onboard the International Space Station. The first crew members to trade places Saturday morning were Usachev and Gidzenko. Voss and Krikalev will switch out on Sunday. Shepherd won't trade his personalized Soyuz seat liner for Helms' until Tuesday evening, allowing almost a week for the the two commanders to exchange notes. Shepherd remains in control of expedition operations until the hatches close for the final time next Saturday.

The hatches between the two spacecraft were to be closed temporarily about 5:45 a.m. CST Saturday so that preparations for STS-102's first space walk by Helms and Voss can begin on time at 10:47 p.m. CST Saturday. That space walk will involve preparations for berthing of the Leonardo "moving van," or Multipurpose Logisitics Module to the Destiny module.

The orbiting complex is operating in fine shape at an altitude of 235 statute miles.

While their Commander Yury Usachev begins a handover of duties from Expedition One Commander Bill Shepherd aboard the International Space Station, the remaining members of the second station crew, astronauts Jim Voss and Susan Helms, will perform the space walk tonight, which will be the 17th devoted to assembly of the station.

The shuttle crew was awakened this evening by the song "Nothing's Gonna Stop Us Now," performed by Starship and played in anticipation of the planned Extravehicular Activity (EVA). Voss and Helms were scheduled to begin putting on their spacesuits about 7:30 p.m. Throughout the planned seven hour EVA, they will be assisted by Paul Richards, serving as the in-cabin space walk choreographer.

Once outside the shuttle's airlock, their first tasks will be to prepare for the repositioning of Pressurized Mating Adapter 3 - a shuttle docking port - which will be repositioned from the Earth-facing berth on the Unity module to its left-side berth. They will detach cables on that docking port and also detach a communications antenna from the left-side berth on Unity. Then their work will focus on preparing the exterior of the station's Destiny Laboratory for the arrival of the space station robotic arm that will be launched aboard Endeavour next month. They will attach an exterior cradle to the lab as well as cables that will be used for the arm's installation.

After about six hours of work, Voss and Helms will return to Discovery's airlock where they will stand by, ready to assist if needed, as Andy Thomas uses the shuttle's robotic arm to reposition the docking port. After more than seven hours outside, they plan to repressurize the airlock and enter Discovery's cabin at about 6:12 a.m. Sunday.

The hatches between Discovery and the International Space Station are closed now after having been opened for only a couple of hours early this morning just after Discovery docked to the complex. Usachev immediately moved to the station from the shuttle and Yuri Gidzenko, pilot for the first station crew, moved to Discovery. The hatches between the two spacecraft are to be reopened shortly after 8 p.m. Sunday, as the crew begins the fifth day of the mission.

Discovery and the station are in excellent condition in an orbit with a high point of 237 statute miles and a low point of 230 statute miles.

The pair, destined to become members of the Expedition Two crew aboard the station later in the mission, began the 17th station assembly space walk at 11:12 p.m. CST Saturday. Inside Discovery, Paul Richards choreographed their activities and served as liaison with Mission Control.

The space walkers were delayed early in their excursion when a portable foot restraint attachment device became untethered, and Voss had to retrieve a spare from its storage location on the outside of the station's Unity module.

Helms and Voss successfully prepared Pressurized Mating Adapter-3 for repositioning from Unity's Earth-facing berth to its port-side berth to make room for Leonardo, the Italian Space Agency-built Multipurpose Logistics Module. They disconnected eight cables and removed an Early Communications System antenna from the left-side Common Berthing Mechanism so that shuttle robotic arm operator Andy Thomas could put the mating adapter in its place, freeing up the Earth-facing berthing port for Leonardo.

The space walkers also removed a Lab Cradle Assembly from the cargo bay and installed it on the side of the Destiny laboratory module, where it will form the base for station robotic arm to be launched on STS-100 in mid-April. Because of the early delay, they were instructed to defer power and data cable connections for the cradle until Monday's scheduled space walk by Richards and Thomas. Voss and Helms also installed a cable tray to Destiny for later use by the station's robot arm.

The pair reentered Discovery's airlock early Sunday and waited for Thomas to maneuver the docking port to its new location, but remained at the ready to assist if needed. After Commander Jim Wetherbee drove the Common Berthing Mechanism latches home and secured the docking port at 7:43 a.m., the airlock was repressurized, ending the space walk at 8:08 a.m. Sunday after 8 hours 56 minutes, making it the longest space walk in Shuttle history. The space walk brings the total exterior construction time on the station to 117 hours 39 minutes over the course of 17 space walks, and the total EVA time in Shuttle program history to 386 hours, 15 minutes over 61 separate space walks.

Meanwhile aboard the station, Expedition Two Commander Yury Usachev began a handover of duties from Expedition One Commander Bill Shepherd, with Flight Engineer Sergei Krikalev also still on board. The hatches between Discovery and the International Space Station are to be reopened shortly after 8 p.m. Sunday, as the crew begins the fifth day of the mission.

Both crews are scheduled to begin an eight-hour sleep period at 9:42 a.m. central time, awakening at 5:42 p.m. Discovery and the station are in excellent condition in an orbit of about 235 statute miles.

Discovery's crew was awakened today by the song "Blast Off" from the animated feature Scooby Doo and the Alien Invaders, played for astronaut Paul Richards as a selection from his children. The shuttle and station crews plan to reopen hatches between the two spacecraft at about 8:12 p.m. today. They will remain open for about eight hours before they again must be closed in preparation for a second space walk Monday night.

Just after the hatches open this evening, the crew exchange will continue with Expedition Two Flight Engineer Jim Voss taking up residence aboard the station and Expedition One Flight Engineer Sergei Krikalev moving to Discovery. With Expedition Two Commander Yury Usachev already aboard the complex since Saturday, only one more crewmember switch remains to complete the station's change of watch. Expedition One Commander Bill Shepherd will trade places with Expedition Two Flight Engineer Susan Helms Tuesday night.

As the crews work together tonight, moving gear inside the shuttle and station, Astronaut Andy Thomas will use Discovery's robotic arm to remove the Italian Space Agency-built Leonardo Multi-Purpose Logistics Module from the shuttle's cargo bay and attach it to the station's Unity module. Leonardo carries more than 5 tons of equipment and experiments that will be unloaded during the next few days before it is again detached from the station and stowed aboard Discovery to return to Earth.

Tonight's plan calls for Thomas to begin lifting Leonardo from Discovery's cargo bay at 9:12 p.m. He will maneuver it into place and latch it to the station at about 10:57 p.m. The station crew plans to enter the cargo module at about 5:42 a.m. Monday to begin the unloading.

Discovery and the International Space Station remain in excellent condition in an orbit with a high point of 236 statute miles and a low point of 229 statute miles.

Operating Discovery's robotic arm, Thomas grappled the "crate" full of equipment racks and supplies at 9:37 p.m. Sunday, lifting it out of the shuttle's cargo bay at 10:10 p.m. Over the course of the next two hours, he slowly and deliberately moved the 11-ton module into place. At 12:02 a.m. today, STS-102 Commander Jim Wetherbee commanded the latches on the station's Earth-facing Common Berthing Mechanism to establish a tight seal with the Leonardo module.

The berthing of Leonardo to Unity took slightly longer than planned while Expedition One Commander Bill Shepherd rerouted video from the Centerline Berthing Camera System to the television monitors on the shuttle's aft flight deck so that Thomas could use the view looking directly out the berthing port at its corresponding opening on Leonardo. There also was a delay in activating the cargo carrier while Shepherd connected a Unity-to-Destiny power cable that provides electricity to systems inside Leonardo. Shepherd briefly entered the Leonardo module at 5:51 a.m. to retrieve the cable. He took it to the vestibule between the U.S. laboratory and Unity and made the required connections. Leonardo carries more than five tons of equipment and experiments that will be unloaded during the next few days before it is again detached from the station and stowed aboard Discovery to return to Earth.

The shuttle and station crews rejoined each other at 9:15 p.m. Sunday when the hatches separating them during the previous day's record-setting 8-hour, 56-minute space walk were reopened. With the hatches open, Jim Voss - the station's newest resident after a 10:45 p.m. swap-out with Sergei Krikalev - joined Expedition One Commander Bill Shepherd and Expedition Two Commander Yury Usachev on board the station. Only one more crew swap remains to complete the station's change of watch. Expedition One Commander Bill Shepherd will trade places with Expedition Two Flight Engineer Susan Helms on Tuesday. The hatches were closed once again at 5:39 a.m. today after 8 hours, 24 minutes. So far, the hatches between the shuttle and station have been open for a total of 10 hours, 27 minutes.

Meanwhile mission specialists Paul Richards and Thomas, with help from Helms, checked out the space suits they will wear for a planned 6-hour, 30-minute space walk scheduled to begin at 10:47 p.m. Monday. Richards and Thomas will finish up a task that was deferred from the first space walk, connecting cables on the Lab Cradle Assembly that will be the mounting location for the station's robotic arm when it arrives next month. Next, they'll install an External Stowage Platform on the hull of Destiny and hook up cables that will provide heater power to spare equipment that will be stored there. They'll place the first of such spares, a Pump and Flow Control Subassembly that regulates ammonia coolant flow, on the platform. The pair also will inspect the Floating Potential Probe that is designed to measure the electrical charge on the outside of the station but has not been providing data since being temporarily shut down for repositioning of the station's Soyuz escape vehicle in February.

Discovery and the International Space Station remain in excellent condition at an altitude of about 235 statute miles.

The song "From a Distance" performed by Nanci Griffith awakened Discovery's crew, and astronauts Paul Richards and Andy Thomas quickly began preparing for a planned six and a half hour space walk. Richards and Thomas plan to install a stowage platform for spare station parts as well as attach a spare pump to the platform, ready in the event future crews need it. They also will complete the connection of several cables that were put in place by astronauts Jim Voss and Susan Helms during their space walk conducted on Sunday. The cables, on the exterior of the Destiny laboratory, will be used by the station's robotic arm set for launch aboard the next space shuttle in April.

After the cable connections are completed, Richards and Thomas will climb to the top of the station where the giant, 240-foot wingspan United States solar arrays are attached and attempt to tap a brace for the port side array into its latched position. The brace, one of four, did not latch in place properly when the arrays were installed on the station last year. However, the other three braces are secure and the array's stability has not been a concern. In addition, several quick tasks are planned during the space walk, including work with a connector on the Unity module as part of an analysis of a past lab heater problem; taking photos of a vent on the Destiny lab and of the Zvezda service module's general exterior; and inspecting an exterior experiment called the Floating Potential Probe that has operated intermittently since it was installed on the station a few months ago.

During the space walk, Discovery Pilot Jim Kelly will operate the shuttle's robotic arm to maneuver Thomas as he carries gear between the shuttle and the station. Astronaut Susan Helms will serve as the in-cabin space walk coordinator aboard Discovery.

While Discovery's crew is busy installing exterior equipment, inside the station Expedition One Commander Bill Shepherd, Expedition Two Commander Yury Usachev and Expedition Two Flight Engineer Jim Voss will continue unloading the Leonardo logistics module. Leonardo, attached to the station last night, carried almost five tons of gear to be installed aboard the complex.

Richards and Thomas are scheduled to begin donning their space suits and associated gear at about 7:42 p.m. and exit Discovery's cabin at 10:47 p.m. The space walk is scheduled to conclude at 5:17 a.m. Tuesday.

Discovery and the International Space Station continue to orbit in excellent condition.

With help from shuttle robotic arm operator Jim Kelly and space walk choreographer Susan Helms, Richards and Thomas installed a stowage platform for spare station parts and attached a spare ammonia coolant pump to the platform. They also finished connecting several cables put in place by Astronauts Jim Voss and Susan Helms during their nearly nine-hour-long space walk Sunday. The cables, on the exterior of the Destiny laboratory module, will provide power and control of the station's Canadian-built robotic arm. Known as the Space Station Remote Manipulator System, the arm will be delivered and installed by the STS-100 crew in April.

Commander Jim Wetherbee deactivated and then reactivated Leonardo's DC-to-DC power converters and checked out the Lab Cradle Assembly, installed during the first space walk, which eventually will be used to connect the station's large truss structure to Destiny's hull.

Richards and Thomas also scaled the station to the top of its 240-foot-wide solar arrays and were successful in engaging a fourth latch for the port-side array's structural brace. Several other get-ahead tasks also were accomplished during the space walk, including a check of a Unity module heater connection and inspection of an exterior experiment called the Floating Potential Probe that has been operating intermittently. The space walkers reported they did not see any status lights on the probe; investigators on the ground will use that information to continue troubleshooting.

"Well, Andy, we were on top of the world there for a while," Richards said as the pair began returning to the airlock. "Yes, we were," Thomas replied.

The second and final planned space walk of the mission began at 11:23 p.m. Monday, and concluded at 5:44 a.m. Tuesday. The 6-hour, 21-minute space walk brings the total exterior construction time on the station to 124 hours over the course of 18 space walks, and the total EVA time in shuttle program history to 392 hours, 36 minutes over 62 separate space walks.

As Richards and Thomas worked outside the station, returning Expedition One Cosmonauts Yuri Gidzenko and Sergei Krikalev - now members of the Discovery crew - exercised inside the shuttle to help prepare their bodies for the return to Earth after four and a half months in orbit.

Inside the station, Expedition One Commander Bill Shepherd, and Expedition Two Commander Yury Usachev and Flight Engineer Jim Voss continued to unload the Leonardo logistics module. Among the five tons of gear being transferred is the first station research rack, the Human Research Facility, which will be installed inside Destiny this evening.

Discovery's crew will go to bed at 9:42 a.m. CST, and will get an extra half-hour of sleep before being awakened at 6:12 p.m. All station and shuttle systems are working well.

Discovery's crew was awakened this evening for the seventh day of the mission with the song "Free Fallin" by Tom Petty, a favorite of astronaut Susan Helms who today will take up official residence on the station as a member of the outpost's second crew. She will trade places with first expedition Commander Bill Shepherd, who is completing four and a half months aboard the complex. Though the crew transfer is complete tonight, the official end of the Expedition One increment occurs on Saturday when Discovery departs the ISS.

Usachev, Helms and Jim Voss are beginning a four-month stay in space. Shepherd, Flight Engineer Sergei Krikalev and Pilot Yuri Gidzenko have brought the station to life as members of the inaugural crew, launched Oct. 31, 2000, aboard a Russian Soyuz spacecraft from Kazakhstan. Both the first and second station crews will have several hours set aside today to compare notes and hand over duties.

The crews are ahead of schedule in unloading the Leonardo logistics module, with all seven systems racks - equipment that includes electronics, communications gear, experiments and medical facilities - already moved to the station's Destiny Laboratory. Included among those racks is the first major piece of station science equipment, called the Human Research Facility, which will study the effects of weightlessness on the human body. They will continue unloading supplies from the Italian Space Agency-developed cargo carrier today.

Helms, a Portland, Oregon, native, Usachev, Voss and Discovery Commander Jim Wetherbee will take a brief break from their work just after midnight for an interview with three Portland-area television stations.

Discovery and the International Space Station remain in excellent condition, orbiting Earth once every 92 minutes.

The crews will spend today packing trash and unneeded equipment as well as luggage for the returning station crew in the Leonardo logistics module. They also will have some time off to rest after a busy week spent in space so far. The station crews also will continue comparing notes and handing over duties aboard the scientific outpost. During the handover activities, Expedition Two Flight Engineers Jim Voss and Susan Helms will begin a thorough checkout of the robotic workstation inside the Destiny Laboratory. It will be used to operate the station's Canadian-built remote manipulator system upon its arrival on the next shuttle mission next month.

The crews were awakened today with the song "Should I Stay, or Should I Go?" performed by The Clash, played for returning International Space Station Expedition One Commander Bill Shepherd from his wife, Beth.

Early this morning, near the end of the crew's seventh day in orbit, Discovery Commander Jim Wetherbee performed a reboost of the station and shuttle a day earlier than originally planned to ensure that the complex would remain clear of a piece of spacewalking equipment that floated free during the mission's first spacewalk. The approximately 50-minute long reboost, performed by gentle, repeated firings of Discovery's smallest steering jets, raised the station's and shuttle's orbit by almost two and half statute miles, keeping the complex well away from the lost foot restraint. Two more reboosts for the station are planned to take place later in the flight as originally scheduled for the mission.

Several crewmembers will take breaks from their work tonight to speak with media and students. At 2:17 a.m. Thursday, Wetherbee and Discovery Pilot Jim Kelly will field questions from three media from the Burlington, Iowa, area, Kelly's hometown. At 3:40 a.m., the crew is expected to send a message honoring the 75th anniversary of rocketry. Two hours later at 5:40 a.m., Wetherbee, Shepherd, Expedition Two Commander Yury Usachev, and Discovery astronaut Andy Thomas will field questions from school children in Dundee, Scotland.

Discovery and the International Space Station remain in excellent condition in an orbit with a high point of 243 statute miles and a low point of 230 statute miles.

Helms was the third and final Expedition Two crew member to make the move, following Commander Yury Usachev and fellow Flight Engineer Jim Voss. Helms traded places with Expedition One Commander Bill Shepherd, who now joins Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev as a member of the STS-102 crew aboard the Space Shuttle Discovery. Though the crew transfer is complete, the official end of the Expedition One increment will occur Saturday when Discovery undocks at 9:54 p.m. CST.

Just after completing the transfer, Helms, who calls Portland, Oregon, home, floated into an interview with three Portland-area television stations wearing her Sokol space suit, which she would use in the unlikely event the crew needed to return home in the Soyuz capsule. The Expedition Two crew is scheduled to return home aboard the Space Shuttle Endeavour in July following the second station crew exchange.

The hatches between Discovery and the station remain open and cargo transfer activities continue ahead of schedule. More than 70 percent of the equipment and supplies already has been moved from the Italian-built Leonardo Multi-Purpose Logistics Module into the station. All seven systems racks - equipment that includes electronics, communications gear, experiments and medical facilities - already are in the Destiny laboratory. Included among those racks is the first major piece of station science equipment, called the Human Research Facility, which will study the effects of weightlessness on the human body. The remaining cargo to be transferred consists of supplies in soft-sided transfer bags.

Commander Jim Wetherbee also conducted two tests using the shuttle's steering jets, looking at the potential for using the shuttle's primary reaction control system thrusters to control station attitude and at the optimum method for reboosting the station using those jets. Wetherbee also set up the shuttle's autopilot to reboost the station overnight, eventually raising the station's altitude by about 8.5 statute miles.

Both crews begin their sleep periods at 9:42 a.m. today. They will be awakened at 5:42 p.m. Wednesday.

On Saturday, after two more days of cargo transfers and the return of the Leonardo module to the shuttle's cargo bay, the crews are scheduled to exchange farewells and close the hatches at 7:12 p.m. CST.

Discovery and the International Space Station remain in excellent condition, orbiting Earth at an altitude of approximately 235 statute miles.

Expedition Two Flight Engineers Jim Voss and Susan Helms spent most of their workday installing the Space Station Remote Manipulator System workstation inside the Destiny Laboratory. They activated a portion of the system that will be used to route television pictures from docked space shuttles to the control station for use by arm operators. The remaining activation work will start after Discovery undocks Saturday evening.

The Canadian-built appendage will be delivered on the STS-100 mission - set to launch April 19 - and attached to the Lab Cradle Assembly that Voss and Helms bolted to the side of the Destiny Laboratory Module during their space walk Sunday. The station arm's first job will be to install the airlock on STS-104, set for launch this June.

Load master Andy Thomas coordinated the transfer of equipment, supplies, trash and luggage between the station and shuttle with the help of Expedition Two Commander Yury Usachev and fellow Mission Specialist Paul Richards. All five tons of equipment and supplies delivered aboard the Leonardo Module have been transferred to the station. The crew is now concentrating on packing trash, unneeded equipment and luggage in the Italian-built Multi-Purpose Logistics Module for return to Earth.

Commander Jim Wetherbee and Pilot Jim Kelly answered questions posed by reporters in the area of Burlington, Iowa, Kelly's hometown. Wetherbee, Expedition One Commander Bill Shepherd, Usachev and Thomas talked with school children in Dundee, Scotland, who are following the mission because the crew is carrying a piece of the sailing research ship RRS Discovery launched 100 years ago at Dundee.

The astronauts and cosmonauts also took some time off to rest after a busy week and to continue handing over duties aboard the scientific outpost.

The station and shuttle are orbiting in fine fashion at an altitude of 240 statute miles following a 50-minute long series of reboost maneuvers. The gentle, repeated firings of Discovery's smallest steering jets took place a day earlier than originally planned to ensure that the complex would remain clear of a piece of equipment that floated free during the mission's first space walk. Further tracking has shown that the 10.5-pound Portable Foot Restraint Attachment Device is about 20 miles below and in front of the shuttle-station complex. Two more reboosts for the station are planned Friday and Saturday.

Mission Specialist Andy Thomas coordinated the loading of about a ton of materials and equipment into the Italian-built Multi-Purpose Logistics Module with help from Pilot Jim Kelly and Mission Specialist Paul Richards. The astronauts are to exit the module at 8:42 p.m. CST, deactivate it at 9:02 p.m. and uncouple it from the station at 11:52 p.m. Using the shuttle's robotic arm, they are to latch it in the payload bay at 12:57 a.m. Sunday.

Commander Jim Wetherbee set in motion the third and final reboost of the station's altitude by executing a programmed series of gentle steering jet firings. The third reboost raised the shuttle altitude two statute miles, making the total reboost imparted during the STS-102 mission a little more than seven statute miles.

Departing Expedition One Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev concentrated on sharing their handover notes with Expedition Two Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss.

Kelly, Richards and Thomas took time to answer questions from NBC News' Weekend Today Show and ABC News. About an hour later, Usachev, Gidzenko and Krikalev talked with reporters gathered in the Russian Mission Control Center in Korolev, outside Moscow.

Discovery is scheduled to undock from the station at 10:32 p.m. Sunday. When Discovery undocks from the station, it will mark the end of the Expedition One crew's 136-day stay onboard the outpost, beginning with their Nov. 2 arrival onboard a Soyuz spacecraft.

The shuttle and station remain in excellent health orbiting Earth at an altitude of approximately 235 statute miles.

The hatches between the shuttle and station were to be closed for a final time at about 7:30 tonight, leaving Expedition Two Commander Yury Usachev and his Flight Engineers, astronauts Jim Voss and Susan Helms, aboard the complex. The second crew is beginning a four-month stay aboard the station that will see the complex continue to grow in research capability and self-sufficiency as a robotic arm, more experiments and a new airlock are attached on future missions.

The first station expedition crew - led by Commander Bill Shepherd with Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev - is returning home after having brought the complex to life during its stay. The Expedition One crew docked to an uninhabited station that was about half the size and had only a fraction of the capability of the orbiting science complex and permanent home they are departing. The crews bid one another farewell about an hour before the hatch closing.

"We are on a true space 'ship' now, making her way above any Earthly boundary," Shepherd said as he handed command to Usachev.

"This ship was not built in a safe harbor but on the high seas," Discovery Commander Jim Wetherbee added.

During the almost nine days Discovery has been docked at the station, the crews unloaded almost five tons of experiments and equipment and repacked almost a ton of returning items. Discovery's mission also has set the stage for the continued expansion of the station when a Canadian robotic arm is launched aboard the shuttle Endeavour next month. Pilot Jim Kelly will be at the shuttle's helm as Discovery undocks from the station tonight, planned to occur at 10:32 p.m. Kelly will guide Discovery in an hour-long station flyaround where he will circle the station one and a quarter times, 450 feet away, while the crew records television and photos of the exterior.

The hatches between the shuttle and station were closed for a final time at 8:32 p.m., about an hour after departing Expedition One Commander Bill Shepherd passed responsibility for the station to Expedition Two Commander Yury Usachev. As the hatches closed, Usachev, and flight engineers Jim Voss and Susan Helms marked the start of their four-month stay on orbit. The previous Expedition crew - Shepherd and Cosmonauts Yuri Gidzenko and Sergei Krikalev - are now headed home on board Discovery.

After the undocking -- which occurred as the two vehicles flew over Guyana, South America, and its capital of Georgetown -- Pilot Jim Kelly flew Discovery one-and-a-quarter turns around the space station before initiating a final steering jet separation burn at 11:48 p.m. CST. During the flyaround at a distance of 450 feet the crew recorded television and still images of the station's exterior.

The two vehicles were docked for a total of 8 days, 21 hours, 54 minutes, which brings the total time shuttles have been docked to the station to 55 days, 23 hours, 7 minutes. The hatches were open for a total of 142 hours, 22 minutes during three periods punctuated by space walk-necessitated closures.

Over the course of joint operations between the station and shuttle crews, Discovery Commander Jim Wetherbee, Kelly and Mission Specialists Andy Thomas and Paul Richards worked with the station crew unloading almost five tons of experiments and equipment from the Italian-built Multi-Purpose Logistics Module, and packing almost one ton of items for return to Earth. Discovery's space walkers - Voss and Helms, and Thomas and Richards -- also set the stage for continued expansion of the station by installing a platform that will be used to mount a Canadian-built robotic arm to the station next month.

After undocking, Discovery's crew spent the rest of the day exercising, talking with their families and enjoying some scheduled off-duty time. The shuttle crew will go to sleep at 8:12 a.m. and awaken at 4:12 p.m., while the station crew will begin its sleep shift at 3:30 p.m., awakening at midnight.

There are two landing opportunities available this evening for Discovery's return to the Kennedy Space Center. The first landing opportunity begins with a firing of the Shuttle's orbital maneuvering system engines at 10:50 p.m. for an 11:56 p.m. landing. A second opportunity, one orbit later, begins with a deorbit burn at 12:26 a.m. Wednesday, resulting in a landing at 1:31 a.m. Weather at the Kennedy Space Center is not expected to be favorable today, however, with the possibility of high winds, rain and clouds in the vicinity of the Shuttle Landing Facility. The backup landing site at Edwards Air Force Base in Calif. was called up for landing support this morning and weather conditions are expected to be acceptable there for landing. Flight controllers will continue to monitor the weather at both landing sites and Entry Flight Director Wayne Hale is expected to make a decision regarding landing opportunities shortly after 10:30 p.m. today.

Discovery's astronauts are scheduled to begin their deorbit preparations at 6:53 p.m. today - configuring the shuttle's computers for reentry, deactivating the galley and installing seats on the flight deck and middeck. The payload bay doors are scheduled to be closed at 8:10 p.m.

If given a go to land, Wetherbee and the shuttle crew - Pilot Jim Kelly and Mission Specialists Andy Thomas and Paul Richards will perform a series of procedures that will lead to the firing of the Shuttle's large orbital maneuvering engines later this evening, beginning the crew's hour-long reentry to Earth. Discovery is also bringing home the first occupants of the International Space Station, Expedition One Commander Bill Shepherd and Russian crewmates Yuri Gidzenko and Sergei Krikalev. After 141 days in space, the Expedition One crew will re-enter Earth's atmosphere reclining on seats designed to help ease the stress of gravity and landing on their bodies.

On board the International Space Station, Expedition Two Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss spent a relatively quiet day in space as they enjoyed another day of light activities.

Discovery continues to orbit the Earth in excellent shape at an altitude of 237 statute miles as its astronauts gear up for landing.

Landing is scheduled for 11:56 p.m. CST Tuesday (12:56 a.m. EST Wednesday), but Entry Flight Director Wayne Hale and his team are carefully watching weather conditions at the primary landing site. With low clouds, possible rain and gusty crosswinds expected at Kennedy Space Center in Florida, Hale decided to activate support at Edwards Air Force Base in California on Wednesday when conditions are expected to be at their best this week.

The first landing opportunity begins with a deorbit burn on Orbit 200 at 10:50 p.m. CST Tuesday and ends with landing at 11:56 p.m. in Florida. The second opportunity on Orbit 201 starts with an engine firing at 12:26 a.m. CST Wednesday and ends with landing in Florida at 1:31 a.m. The third chance calls for an Orbit 202 deorbit burn at 1:57 a.m. CST Wednesday and landing at Edwards at 3:02 a.m. The final prospect of the crew day begins with an engine firing at 3:33 a.m. CST Wednesday and ends with a California landing at 4:38 a.m.

Wetherbee and the shuttle crew - Pilot Jim Kelly and Mission Specialists Andy Thomas and Paul Richards - spent the day packing for the trip home and completing checks of the steering jets and flight controls the shuttle will use. They also fired Discovery's orbital maneuvering system engines to adjust the shuttle's orbit and optimize landing opportunities, testing the braking rockets they use to begin re-entering the Earth's atmosphere.

ISS Expedition One Commander Bill Shepherd and crewmates Yuri Gidzenko and Sergei Krikalev took time out from their packing to answer questions posed by three television news reporters. Tonight, the returning Expedition One crew members will set up the reclining seats to help ease the stress of landing on their bodies, which have not experienced gravity for four and a half months.

Meanwhile, the Expedition Two crew aboard the station - Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss - began settling into their new home and shift schedule. Awakening at midnight Tuesday, they began their daily exercise regimen and set up the station toilet for use by its first female crew member.

The crew aboard Discovery is scheduled to begin its sleep shift at 7:42 a.m. CST and wake up to begin final landing preparations at 3:42 p.m. Bedtime for the station crew is 3:30 p.m. CST.

STS-102 Commander Jim Wetherbee fired Space Shuttle Discovery's engines at 12:26 a.m. CST to begin the shuttle's descent. With assistance from Pilot Jim Kelly, he made a smooth landing on Runway 15, the 17th night landing in the shuttle program and the 12th night landing at Kennedy. The shuttle had traveled a total of 5,357,762 statute miles.

Expedition One Commander Bill Shepherd, Pilot Yuri Gidzenko and Flight Engineer Sergei Krikalev, riding home in reclining seats to lessen the stress, felt the tug of gravity for the first time in 141 days following their Oct. 31, 2000, launch to the station aboard a Russian Soyuz capsule. The Expedition One crew will be reunited with their families in Florida this morning, and then begin a medical and rehabilitation period of about 45 days.

Wetherbee, Kelly and Mission Specialists Paul Richards and Andy Thomas had spent a total of 12 days, 19 hours, 49 minutes on orbit. They had conducted a successful rendezvous and docking with the space station complex, supported two space walks to facilitate the first use of the Leonardo Multi-Purpose Logistics Module and installed a station robot arm anchor point. They also witnessed the first station crew changeout, unloaded 5 tons of equipment and experiments, and packed up a ton of unneeded station equipment and trash for return to Earth on Discovery.

All seven spacefarers are expected to return home to Houston on Thursday afternoon.

Entry Flight Director Wayne Hale made the a decision to land in Florida just before midnight after cloudy skies and gusty winds had cleared due to a low-pressure system that raced through the Shuttle Landing Facility area faster than expected Tuesday night.

On board the International Space Station, Expedition Two Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss were expected to hear word of their compatriots' landing later this morning. The trio spent a relatively quiet day in space getting acclimated to their news surroundings and preparing themselves for what will soon be a busy schedule of activiities continuing the outfitting of the space station and beginning scientific research in its Destiny laboratory.

Minor issues being worked by the crew and flight control teams in Houston and Moscow are not impacting the operation and health of the complex, but are occupying time of engineers in preparing troubleshooting procedures for items on board.

The activation of the station's Ku-Band antenna is on standby until procedures are put in place for a possible software patch to account for an apparent pointing error with the dish-shaped antenna. The Ku Band system is used to transmit television, voice and high-speed data to the ground. Normal communication is being managed through the S-Band audio system. Any required TV images, in the meantime, can be accommodated through the use of the laptop computer-based digital video system. Until that problem is corrected, transmission of experiment data from the Human Research Facility experiment rack in the Destiny laboratory is on hold.

A Destiny condensate venting system is not working and while troubleshooting continues, the thermal loop temperatures have been increased so that no water currently is being condensed. As a point of verification, a contingency water container has proven to be useful in serving as a storage location for condensate, if required.

In and around maintenance tasks and routine housekeeping chores, the crew has been busy setting up additional equipment and conducting status checks on some of the payloads. A new bicycle exercise machine called CEVIS (for Cycle Ergometer with Vibration Isolation System) was setup this week, while engineers assess the work needed to repair the station's treadmill, which is showing wear in many of the slats that provide support to the unit designed to allow exercise with little or no vibration that could impact sensitive experiment work.

The Progress supply craft docked to the Zvezda module delivered 89 kilograms of oxidizer to the service module's storage tanks via remote commanding from the ground. The Progress will be undocked from the station in mid-April in preparation for the arrival of the next shuttle flight carrying the station's Canadian-built robot arm and another Italian Space Agency supplied logistics module called Raffaello.

The Progress undocking provides an open port for the relocation of the Soyuz capsule around April 16-18 which will provide clearance for the placement of Raffaello during the shuttle mission, which launches April 19.

Later this week the Expedition Two crew is scheduled to perform some maintenance work in an attempt to get the carbon-dioxide removal assembly in Destiny working. The plan calls for a test of a cable to ensure it is working before changing the pump with a spare brought up on the most recent shuttle flight. As of now, with only three people onboard, carbon dioxide removal from the cabin air is adequately conducted by Zvezda's Vozdukh system.

The crew plans to take part in its first interview opportunity on Friday with reporters from CBS and the Associated Press at 10 a.m. CST Friday. The interview will be broadcast on NASA TV, but will be audio only.

Meanwhile down at the Kennedy Space Center in Florida, the crew of shuttle mission STS-100 is conducting its traditional countdown dress rehearsal in preparation for launch to the ISS April 19. The international crew consists of Commander Kent Rominger, Pilot Jeff Ashby, Flight Engineer John Phillips, Mission Specialist Scott Parazynski, Canadian astronaut Chris Hadfield, European astronaut Umberto Guidoni and Russian Aviation and Space Agency cosmonaut Yuri Lonchakov.

The International Space Station continues to orbit the Earth in good shape at an altitude of 238 statute miles (384 km).

The activation of the station's Ku-Band antenna remains on hold until a software update is uplinked to the station's computers Thursday. This command is designed to correct an apparent pointing error with the dish-shaped antenna. The Ku-Band system is used to transmit television, voice and high-speed data to the ground. Normal communication is being managed through the S-Band audio system. Any required TV images, in the meantime, can be accommodated through the use of the laptop computer-based digital video system.

Also, the crew changed out components of the carbon dioxide removal assembly system in the Destiny Laboratory in an effort to recover its use. Troubleshooting work continues as engineers evaluate what appears to be a sluggish vent valve on the unit. The Zvezda module's CO2 removal system is working fine and providing more than adequate capability to cleanse the cabin air in the meantime.

Oxygen for the crew currently is being provided by supply tanks in the Progress supply vehicle, which boosted the cabin air yesterday. Without the Progress, the Russian Elektron in Zvezda provides oxygen generation. Not presently needed, the Elektron is turned off.

Apart from maintenance tasks and routine housekeeping chores, the crew has been working with experiments on board. The Human Research Facility rack in Destiny is managed and operated by a science and operations team from the Telescience Support Center down the hall from the station's flight control room in Mission Control, Houston. All payloads on the station are overseen from NASA's Marshall Space Flight Center in Huntsville, Alabama where the Payloads Operations Center is located.

The Progress supply craft currently docked to the aft end of the Zvezda module is scheduled to be undocked around April 15 in preparation for the arrival of the next shuttle flight carrying the station's Canadian-built robot arm and a second Italian Space Agency supplied logistics module called Raffaello. The open port allows for the relocation of the Soyuz capsule around April 17, which will provide clearance for the placement of Raffaello during the docked phase of the shuttle mission. The Flight Readiness Review to evaluate the readiness of Endeavour, its crew and the station for the shuttle's launch on the STS-100 mission will be held Thursday to select a target launch date, which currently is around April 19.

Earlier today, a small test firing of the Progress supply ship's thrusters was performed to verify command capability of the steering jets via the Zvezda module's computers. The brief engine burn resulted in a change in the velocity of the Station of only one meter per second. It was the first time the Progress thrusters were commanded from the ground through the Zvezda module's computers.

The test sets the stage for another Progress engine firing early next week designed to refine the orbit of the station relative to the Baikonur Cosmodrome in Kazakhstan in preparation for the arrival of a new Soyuz capsule to replace the one presently docked to the station. Soyuz capsules routinely are changed about every 180 days. A taxi crew, as it's called, will deliver the new capsule and return to Earth in the one launched last October carrying the station's first Expedition Crew.

Late Tuesday, a handover of the station's attitude control from the electrically driven Control Moment Gyroscopes to the Zvezda module's thrusters was performed as a test to verify that the automatic switchover would occur in the event that the CMGs developed a problem. The test allowed the system to 'think' that the gyros had failed down to one operational system and the computers automatically switched to the thrusters. The test verified the system is fully operational.

The International Space Station continues to orbit the Earth in good shape at an altitude of 238 statute miles (384 km).

Remaining fuel and oxidizer from the Progress vehicle was transferred into tanks on the Russian Zvezda module yesterday and today, and plans call for final fuel and oxidizer transfer to the Zarya module tomorrow and Friday. The Progress engines were fired earlier this week in a small reboost maneuver that verified for the first time a command link of the thrusters through the Zvezda module's computer.

The Progress is scheduled to be remotely undocked from Zvezda's aft docking port about 3:30 a.m. CDT Monday after which it will be deorbited to burn up harmlessly in the Earth's atmosphere. The relocation of the Soyuz spacecraft that delivered the first expedition crew to the station is planned for 7:30 a.m. April 18. The 35 minute procedure calls for the three crewmembers to climb aboard the Soyuz, undock from a docking port on Zarya and fly-around to the aft docking location on Zvezda. This will provide the necessary clearance for the Raffaello Multi Purpose Logistics Module's (MPLM) attachment to the Unity module's nadir port during STS-100.

The resident crew of the International Space Station - Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms - is nearing the end of its first month aboard the complex, having begun its increment work on March 18.

The activation of the station's Ku-Band communication system is essentially complete and several television downlinks this week have shown the crew in its daily routine of experimenting, housekeeping and maintenance aboard the station. One of the major tasks accomplished is a complete checkout of two Robotic Work Stations, which will serve as the command and control locations for the station Remote Manipulator System, known as Canadarm2.

The high-tech robot arm and the second Italian Space Agency-built MPLM are the major cargo aboard Endeavour. The seven-person crew will fly to Florida Monday morning for the final three days of the countdown to launch. The countdown is set to begin at 5 p.m. CDT Monday leading toward liftoff at 1:41 p.m. CDT April 19. An on time launch will see Endeavour dock to the station at about 8:36 a.m. CDT April 21.

In and around preparations for the Progress departure, the Soyuz fly-around and upcoming shuttle arrival, the Expedition crew continues to conduct science investigations aboard the ISS. With the station's Ku-band television system working, experimenters are working to activate the Human Research Facility (HRF) rack in the Destiny Laboratory and are preparing for the arrival of new racks of experiments on the upcoming shuttle visit. The HRF is managed and operated by a team in the Telescience Support Center at the Johnson Space Center. The International Space Station continues to orbit the Earth in good shape at an altitude of 240 statute miles (386 km).

Commander Kent Rominger, Pilot Jeff Ashby and Mission Specialists Chris Hadfield of the Canadian Space Agency, John Phillips, Scott Parazynski, Umberto Guidoni of the European Space Agency and Yuri Lonchakov of Rosaviakosmos blasted off on time from Launch Pad 39-A at 1:41 p.m. Central time as the ISS sailed over the Indian Ocean south of India. Aboard the station, Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms were told of Endeavour's launch as it lifted off from the pad. Approximately 20 minutes later, the three crew members took a few minutes out from routine maintenance work and preparations for Endeavour's arrival to watch a video feed of the launch uplinked to them by ISS flight controllers in Houston through the station's KU-band communications system.

Less than nine minutes after launch, Endeavour had reached its preliminary orbit and began its pursuit of the station for a docking Saturday morning. The seven astronauts began to configure systems for on-orbit operations and opened the shuttle's cargo bay doors before the start of an eight-hour sleep period tonight at 6:41 p.m. Central time.

Aboard the ISS, all systems continue to function normally as Usachev, Voss and Helms ready the complex for their first visitors since beginning their expedition one month ago. On Monday, a Russian Progress resupply vehicle was jettisoned from the aft docking port of the Zvezda module, enabling the station crew to undock its Soyuz return capsule from the nadir port of the Zarya module yesterday and fly it to a redocking with Zvezda in a 21-minute maneuver. That cleared the Zarya docking port for the arrival of the Soyuz rotation "taxi" crew at the ISS later this month. The taxi crew will deliver a fresh Soyuz capsule for the Expedition crew members' use as an emergency return vehicle. The Soyuz vehicles need to be rotated approximately every six months.

Hadfield and Parazynski are scheduled to venture outside Endeavour Sunday for the first of two scheduled space walks to unfold the huge booms of the 57-foot-long Canadarm2 and to route power to the device, which will be mounted on the Destiny Laboratory for future station assembly work. Canadarm2 is scheduled to "walk off" its pallet and attach itself to a grapple fixture on Destiny Monday, where it will receive power, data and commanding from the Expedition crew operating at robotic workstations inside Destiny.

Housed in Endeavour's cargo bay is the Italian Space Agency-provided Raffaello cargo module, which is carrying several tons of equipment for the Expedition Two crew and racks of hardware for installation in Destiny which will be used for scientific research in the future. Raffaello, which is the second of three such logistics modules, will be berthed to the ISS Monday so its contents can be transferred to the station throughout the course of docked operations.

Endeavour is circling the Earth in excellent shape as it flies in an orbit inclined 51.6 degrees to either side of the Equator.

Endeavour is scheduled to dock with the station at 8:36 Saturday morning to deliver the Canadian built high tech robotic arm, called Canadarm2 and the Raffaello Multipurpose Logistics Module supplied to the program by the Italian Space Agency. Raffaello contains equipment and supplies for the station and its crew of Commander Yury Usachev, and Flight Engineers Jim Voss and Susan Helms. It also brings two new experiment racks for the station's U.S. laboratory Destiny.

The Endeavour crew, Commander Kent Rominger, Pilot Jeff Ashby and Mission Specialists Chris Hadfield of the Canadian Space Agency, John Phillips, Scott Parazynski, Umberto Guidoni of the European Space Agency and Yuri Lonchakov of Rosaviakosmos were awakened at 2:41 a.m. Friday by "Then the Morning Comes" by the musical group Smashmouth. It was chosen for Phillips, making his first spaceflight.

Today the shuttle crew will checkout three spacesuits and the orbiter's robotic arm while rendezvous preparations include installation of the centerline camera and extension of Endeavour's Orbital Docking System ring. Another rendezvous engine burn is scheduled shortly before the crew finishes today's activities.

Space station crewmembers also will get ready for the rendezvous. Later today they will prepare equipment for transfer to the shuttle shortly after docking.

Endeavour will bring the first visitors to the Expedition Two crew since Discovery's departure last month. Shortly after Endeavour's scheduled undocking and departure from the station on April 28, a taxi crew is to arrive with a new Soyuz spacecraft. It will replace the Soyuz, which launched the first crew toward the station on Oct. 31, 2000. The Soyuz capsule has an on-orbit life of about six months.

Hadfield and Parazynski will conduct two spacewalks on Sunday and Tuesday. The first will focus on installation of the 2-ton, 57-foot-long Canadarm2. The second is devoted to checkout of the arm that will be instrumental in future space station assembly.

Major systems aboard Endeavour and the International Space Station continue to function well.

Endeavour is scheduled to dock with the station at 8:32 a.m. Saturday although the crews will not greet each other until early Monday. In preparation for tomorrow's rendezvous and docking, Hadfield and Parazynski checked out the tools and hardware that will be used during Endeavour's approach to the station, and Commander Kent Rominger and Pilot Jeff Ashby installed a center-line camera in the orbiter docking system.

Rominger, Ashby and Flight Engineer John Phillips performed another in a series of engine firings to refine Endeavour's approach to the Station. As of 5 p.m., Endeavour was approximately 1,400 miles behind and below the station, and closing that distance at the rate of about 171 miles every orbit of the Earth. Hadfield and Parazynski also verified the operation of the spacesuits they will wear on two scheduled space walks to install and activate the new Canadarm2 robotic arm.

European Space Agency astronaut Umberto Guidoni began preparations for the transfer of hardware and material from Endeavour to the station and worked with Ashby in checking out the shuttle's robotic arm to verify its operation. Yuri Lonchakov of Rosaviakosmos worked on the middeck and filled two large water containers for later transfer to the station.

Endeavour's astronauts will go to sleep at 5:41 p.m. today, awakening at 1:41 a.m. Saturday. They will quickly begin the final stages of their chase of the International Space Station. The final intercept burn is scheduled for 6:13 a.m., with docking at 8:32 a.m., as the two spacecraft fly overhead the Southeast coast of China, northeast of Victoria, Hong Kong.

Meanwhile, on the space station, Expedition 2 Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss continued packing return items and making sure their orbiting home is ready for the crew's first visitors. Flight controllers report that the Russian segment's carbon dioxide removal system is not working at its highest rate, probably due to a clogged filter screen. The situation poses no problems for the upcoming shuttle visit, but could lead to increased use of backup lithium hydroxide removal systems after the shuttle undocks and additional crew members arrive on a Soyuz taxi flight. The station crew may be asked do some repairs on the unit on Saturday.

Otherwise, all major systems aboard Endeavour and the International Space Station continue to function well.

Before the undocking a week later, two space walks will have been conducted and Raffaello, the second Multipurpose Logistics Module provided by the Italian Space Agency, will have been unloaded and reloaded after berthing to the station. The pressurized cargo carrier - an orbital moving van - is bringing food, equipment and other supplies, as well as two scientific experiment racks for the U.S. laboratory Destiny.

Endeavour will approach the station from behind and below. Commander Kent Rominger and Pilot Jeff Ashby, assisted by the rest of the crew, will fly the shuttle to a point about 600 feet directly below the station. With the cargo bay pointed toward the station, they will fly a quarter circle to a point about 300 feet ahead of the station. From there they will begin a slow approach to the docking port at the forward end of Destiny. Stationkeeping will begin at a distance of about 30 feet to ensure a good alignment with the station's docking target before Rominger resumes the approach at a speed of about one foot every 10 seconds until docking.

Kenny Loggins' "Danger Zone" awakened Endeavour's crew - Rominger, Ashby and Mission Specialists Chris Hadfield, John Phillips, Scott Parazynski, Umberto Guidoni and Yuri Lonchakov - early this morning. The song from the Top Gun soundtrack was played for Rominger.

The space station's crew was awakened shortly after 2 a.m. to make final preparations for the shuttle's arrival. The Expedition Two crew of Russian Commander Yury Usachev and astronauts Jim Voss and Susan Helms has been aboard the station for more than a month since assuming duty from the Expedition One crew on March 18.

Though joined together, the two crews will not meet face-to-face until early Monday, after the first space walk by Hadfield and Parazynski. Endeavour's cabin pressure was lowered to 10.2 pounds per square inch Friday afternoon in preparation for that space walk, while the atmosphere inside the station remains a normal 14.7 psi.

The first space walk, scheduled to begin about 6:20 a.m. Sunday, will focus on installation of the station's robotic arm, called Canadarm2. The space walkers also will install a UHF antenna on the station's exterior. Their second space walk Tuesday, features routing power and checking out the stations arm, which at 57.7 feet long, is longer, more flexible and more powerful than the robotic arm used by the shuttle fleet. If necessary, a third space walk could take place Thursday.

All systems are in good shape aboard both vehicles.

Rominger, Pilot Jeff Ashby and Mission Specialists John Phillips, Chris Hadfield, Umberto Guidoni, Scott Parazynski and Yuri Lonchakov, briefly opened a hatch leading from the Shuttle into Pressurized Mating Adapter-2, and retrieved a battery-powered drill for use on Sunday's space walk. They also left behind some supplies that were later retrieved by the station crew. From the station side of the hatch leading to PMA-2, flight engineer Jim Voss used a video camera to film the smiling Shuttle crew members as they transferred four water containers, computer equipment, some fresh food and film for the IMAX camera.

Though securely linked together, the two crews are not scheduled to greet one another in person until early Monday, following the first space walk to be conducted Sunday by Hadfield and Parazynski. Late in their day, Hadfield and Parazynski were joined by space walk coordinator Phillips in conducting some final checks of the suits and hardware that will be used during tomorrow's planned 6 ½ hour space walk. The full crews on both vehicles then reviewed the procedures to be followed throughout Hadfield and Parazynski's space walk.

This first space walk, scheduled to begin about 6:20 a.m., will focus on installing the station's robotic arm, called Canadarm2, and attaching an ultrahigh frequency (UHF) antenna on the station's exterior. A second space walk is scheduled for Tuesday, and will focus on establishing power connections and checking out the new 57.7 foot-long robotic arm.

Expedition Two Commander Yury Usachev and Flight Engineer Susan Helms verified the performance of the station's carbon dioxide removal system, called Vozdukh, which had been operating in a slightly degraded condition. The system started working normally overnight on its own, and their checkout confirmed that it is operating within normal parameters. Usachev, Helms and Voss also exercised and continued preparations for the next week of joint operations with the Shuttle crew.

All systems are in good shape aboard both vehicles. The Station crew will go to sleep at 5:31 p.m. today, followed 10 minutes later by the crew of Endeavour. Mission Control will awaken the shuttle crew at 1:41 a.m. Sunday and the station crew will hear its wake-up alarm tone at 2:01 a.m.

Mission Control Houston recognized the importance of today's activities sending up a congratulatory message from Canadian Astronaut Steve MacLean and playing the Canadian anthem, "Oh Canada" before the two space walkers - Scott Parazynski and Chris Hadfield - floated back into Endeavour. Hadfield became the first Canadian to conduct a spacewalk today as he worked to install the Canadian built and provided Canadarm2 robotic arm.

"It really just opens the door to what all of us can be doing here internationally, beginning to explore space as a planet," said Hadfield.

Parazynski and Hadfield spent 7 hours and 10 minutes working outside the station, installing first an Ultrahigh Frequency (UHF) antenna before turning their attention to the station's new robotic arm. They floated out of Endeavour's airlock at 6:45 a.m. central time and about two hours later had installed and deployed the UHF antenna on the Destiny module of the station.

With that complete, the two astronauts turned their attention to installing the new station robotic arm. The main boom was deployed at 10 a.m. central, and a few minutes later, at 10:10 a.m. Hadfield and Parazynski began unfolding the arm as Endeavour and the station flew 238 miles over the Atlantic Ocean.

With the new arm secured in its pallet attached to the exterior of the Destiny laboratory, Hadfield and Parazynski connected cables to give the arm power and allow it to accept computer commands from inside the lab. After unfolding the arm, they used a pistol grip tool to properly secure a series of expandable fasteners that keep the booms rigidized in position. The two space walkers experienced some difficulty ensuring an appropriate torque level had been placed on the fasteners. By taking the pistol grip tool from automatic to manual mode, Hadfield and Parazynski securely tightened the bolts in place, completing their activities for the day and beginning to clean up the payload bay before returning to Endeavour.

Today's spacewalk, which concluded at 1:55 p.m., was the 19th conducted to assemble the International Space Station. A second spacewalk scheduled for Tuesday will focus on establishing permanent power connections between the arm and station and performing a thorough checkout.

At 1:53 p.m., Flight Engineers Susan Helms and Jim Voss, on board the station, commanded the first motion of the new station robotic arm as they flew 242 miles over the Indian Ocean crossing the eastern coast of Africa. All indications are that the arm operated perfectly in this initial commanding.

Tomorrow, just before 5:30 a.m., Helms and Voss will "walk" the arm off the pallet and attach it to a grapple fixture on the Destiny module. On Wednesday morning, they will use the station arm to hand the pallet to the shuttle arm. In a procedure that will take about 3 ½ hours from start-to-finish, the pallet will be transferred from one arm to the other and berthed back in Endeavour's payload bay for return to Earth

Endeavour's 50 foot-long robotic arm will be pressed into service once again Monday morning as Pilot Jeff Ashby grapples the Italian Space Agency-provided "Raffaello" logistics module and docks it to the Unity module. Early Tuesday morning, the Expedition Two crew - Voss, Helms and Commander Yury Usachev - will enter Raffaello and begin transferring the supplies, equipment and experiment racks loaded inside.

After a busy day on orbit for both crews, the station crew will go to sleep at 5:31 p.m., followed 10 minutes later by Endeavour's crew. Mission Control will wake up Commander Kent Rominger, Ashby, Mission Specialists John Phillips, Yuri Lonchakov, Umberto Guidoni, Hadfield and Parazynski at 1:41 a.m. Monday. The station crew is scheduled to wake up at 2:01 a.m.

Shortly after crew wakeup, Canadian Space Agency astronaut Chris Hadfield and Scott Parazynski began suiting up for the six and a half hour space walk that marks the 19th devoted to the assembly of the ISS and the 63rd in the history of the shuttle program. Hadfield will be wearing a spacesuit with red stripes around the legs, while Parazynski's suit will have no markings. John Phillips will serve as the in-cabin quarterback for the space walk as Pilot Jeff Ashby and European Space Agency astronaut Umberto Guidoni operate the shuttle's robotic arm to install the new arm on the outside of the Destiny laboratory.

Hadfield and Parazynski will connect cables to give the arm power and allow it to accept computer commands from the lab. They will unbolt the arm from the pallet, then unfold its two booms and tighten bolts to make them rigid. The space walkers also will install a UHF antenna on Destiny.

The Space station's Expedition Two crewmembers Jim Voss and Susan Helms will power up the arm from the Robotic Work Station inside Destiny, checking connections made by the space walkers.

A second space walk is scheduled for Tuesday, and will focus on establishing permanent power connections between the 57.7 foot-long arm and station and running it through a thorough checkout.

The shuttle crew was awakened earlier this morning by Canadian Stan Roger's "Take It From Day to Day" played for Hadfield in honor of the space walk - the first ever by a Canadian. The Expedition Two crew was awakened shortly after the shuttle crew.

Endeavour's cabin pressure will be increased to match that of the station during the space walk leading toward opening of the hatches between the shuttle and station Monday morning. Endeavour docked with the station at 8:59 a.m. Saturday followed soon after by entrance into the docking port on the station to retrieve some tools for use during today's space walk. The shuttle crew left behind four water containers, fresh food, computer equipment and IMAX camera film for the station crew.

Hatch opening was set for 4 a.m. following a wakeup call from Mission Control earlier this morning. Judy Collins' "Both Sides Now" for Pilot Jeff Ashby started the shuttle crews' day.

After transfer of equipment and supplies, the hatches will be closed again a little after 2 p.m. so that the Shuttle cabin pressure can once again be lowered to prepare for Tuesday's second spacewalk. That spacewalk will focus on permanently powering the station arm and doing further checkouts.

The 57.7-foot arm was installed and unfolded Sunday during a 7 hour, 10 minute spacewalk by Scott Parazynski and Chris Hadfield. They also installed a UHF antenna on the station's U.S. laboratory Destiny. It was the 19th spacewalk devoted to ISS assembly and the 63rd in the history of the shuttle program.

After additional checkouts by Helms and Voss this morning, the arm will "walk" off the Spacelab Pallet on which it was launched. Its free end will be attached to a Power and Data Grapple Fixture on Destiny, becoming the arm's base. That first step, beginning a little after 5 a.m., will cover just over 24 feet. Wednesday morning, the station arm will hand the pallet to the shuttle arm, to be berthed in Endeavour's cargo bay for return to Earth.

Endeavour's own 50-foot robotic arm, operated by Ashby, will grapple the Raffaello logistics module in the cargo bay and dock it to the Unity module. Its installation there should be complete about 10 a.m. today. Early Tuesday, the Expedition Two crew will begin transferring the food, supplies, equipment and two experiment racks for installation in Destiny from Raffaello to the station.

Both crews are scheduled to end their day about 6:30 p.m. today. Both spacecraft are in excellent shape orbiting Earth every 92 minutes at an altitude of 240 statute miles.

The new 57-foot long Canadian-built Canadarm2 robot arm took its first step this morning, "walking off" a pallet mounted at the top of the Destiny Laboratory to grab onto an electrical grapple fixture on Destiny capable of providing data, power and telemetry to the dexterous appendage.

With Expedition Two Flight Engineer Susan Helms sending commands from a workstation inside Destiny, the arm began to move off the pallet at 6:13 a.m. Central time. Three hours later, after an extensive checkout of all of its new joints, the arm affixed itself to the Destiny grapple point where it will remain overnight in preparation for its first active grappling of a payload --- the pallet on which it was launched --- on Tuesday.

As Canadarm2 was completing its work for the day, Mission Specialist Scott Parazynski used Endeavour's slightly smaller robot arm to latch onto the Italian-built Raffaello cargo module in the Shuttle's payload bay. Raffaello was lifted out of the bay and was attached to a docking port on the Station's Unity module at 11:00 a.m., setting the stage for Expedition Commander Yury Usachev, and Flight Engineers Jim Voss and Helms to begin unloading three tons of supplies beginning tomorrow. Parazynski was assisted by European Space Agency astronaut Umberto Guidoni, who will take the lead in assisting the Station crewmembers in the unloading of Raffaello and the repacking of discarded items in the module later this week.

Parazynski and Canadian Space Agency astronaut Chris Hadfield prepared for their second spacewalk of the mission tomorrow by checking out their tools and spacesuits. They are scheduled to emerge from Endeavour's airlock around 8 a.m. Tuesday for a planned 6 ½ hour excursion to rewire the base of the newly installed Canadarm2 so it can operate from its new home on the Destiny Laboratory, to remove a communications antenna from Unity which is no longer needed and to mount a spare electrical converter unit on a stowage platform on Destiny for future Station use.

Earlier today, Commander Kent Rominger, Pilot Jeff Ashby and Mission Specialists John Phillips and Yuri Lonchakov of the Russian Aviation and Space Agency led the way as hatches swung open between Endeavour and the ISS at 4:25 a.m., allowing the ten crewmembers to greet one another for the first time. Some supplies carried to the Station aboard Endeavour were transferred throughout the day until the hatches once again were closed at 2:26 p.m. after 10 hours of joint operations. The hatch closure enabled the Shuttle's cabin pressure to be lowered to support tomorrow's spacewalk.

Near the end of the day, Rominger and Ashby supervised a one-hour firing of Endeavour's jets to gently raise the orbit of the ISS about 2 ½ statute miles, from 237.8 statute miles to 240.3 statute miles. Two more reboosts are planned on Wednesday and Thursday to leave the Station at the correct altitude for the arrival of a Russian-commanded "taxi" crew next week delivering a fresh Soyuz return vehicle to the complex.

Both crews are scheduled to end their day just after 6:30 p.m. and will be awakened early Tuesday morning. Both spacecraft are in excellent shape orbiting the Earth every 92 minutes.

The Raffaello logistics module, now open for business following yesterday's berthing to the side of the station's Unity module, will be unloaded over the course of the next five days and then reloaded with unneeded cargo from the station for return to Earth.

While the Expedition Two crew of Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms begin to transfer goods from Raffaello, on the other side of the hatch aboard Endeavour, Scott Parazynski and Chris Hadfield planned to conduct the second Extravehicular Activity beginning about 8 a.m.

The first order of business for the veteran spacewalkers will be to connect power, computer and video cables to the Power and Data Grapple Fixture on the side of the station's Destiny laboratory. An antenna on Unity will be removed, as it is no longer needed. Cables on the pallet that carried the new robot arm to the station will be disconnected. Once those cables are removed, the Canadian-built Canadarm2 will be receiving power and communicating with the station's Robotics Work Station inside Destiny.

Near the end of the planned 6-½ hour spacewalk, Helms will command the station's new robotic arm to pick up the 3,000-pound pallet that delivered it to space. She then will maneuver the pallet through various positions to test the arm with a load. Helms will finish today's tests by maneuvering the pallet over Endeavour's payload bay where it will remain parked overnight, still attached to the high-tech robotic arm.

The day began for the astronauts and cosmonauts with the dulcet tones of Louis Armstrong singing "What A Wonderful World." The song was played for Parazynski in honor of today's spacewalk.

Included in the nearly two tons of equipment being off-loaded from the Italian-built Raffaello are two new experiment racks that soon will be filled with science experiments currently in Endeavour's middeck, and other experiments that will be brought to the station on future shuttle missions. Once the hatches are open late this afternoon after the spacewalk, European Space Agency astronaut Umberto Guidoni will take the lead in assisting the station crewmembers in the unloading of Raffaello and the repacking of discarded items in the module for return to Earth.

Both spacecraft are in excellent shape orbiting the Earth every 92 minutes at an altitude of 237 statute miles.

Expedition 2 Flight Engineers Jim Voss and Susan Helms steered Canadarm2 as it lifted its first payload in space, a 3,000-pound pallet that the 57-foot-long arm had been nestled in for launch in the shuttle's cargo bay.

Today's 7 hour, 40 minute spacewalk began at 7:34 a.m. Central time, as Hadfield and Parazynski worked to complete all of the primary goals of the mission, including the connection of the Power and Data Grapple Fixture circuits for the new arm on Destiny, the removal of an early communications antenna and the transfer of a spare Direct Current Switching Unit from the shuttle's payload bay to an equipment storage rack on the outside of Destiny.

As the pair rewired power and data connections for Canadarm2, the backup power circuit failed to respond to commanding from Helms, who was operating from a workstation inside Destiny. Hadfield and Parazynski opened a panel to gain access to another connector at the base of the arm and after disconnecting and reconnecting cables, were able to complete the redundant power path to the arm to the cheers of flight controllers in Houston.

During the removal of the early communications antenna, an electrical connector cover got away from Hadfield and nestled behind a thermal cover in the docking port to which the airlock will be mated in June. After two unsuccessful attempts to locate the errant piece of metal - which required extensive coordination between the shuttle and station flight control teams on the ground -- Hadfield was instructed to stop searching and to move on to other work. The errant component is not expected to have any impact on future operations. With all of their work successfully completed, Hadfield and Parazynski completed their space walk at 3:15 p.m., bringing the total spacewalk time on STS-100 to 14 hours, 50 minutes. A potential third spacewalk on Thursday likely will not be needed.

Expedition Two Commander Yury Usachev and Station crewmates Voss and Helms started their workday transferring supplies, equipment and experiment racks from the Raffaello cargo module, which is berthed to the Unity connecting node.

After the spacewalk was completed, the two crews turned their attention to reopening the hatches between the station and shuttle. Commander Kent Rominger reported that Endeavour's crew had returned to the ISS at 5:15 p.m. to set the stage for the resumption of transfer activities on Wednesday. The two crews will begin their sleep periods shortly after 6:30 p.m.

Both spacecraft are in excellent shape orbiting the Earth every 92 minutes at an altitude of 237 statute miles.

While robotic arm operations are underway by Expedition Two crewmembers Susan Helms and Jim Voss aboard the station, and shuttle crewmembers Chris Hadfield and Scott Parazynski, the remaining shuttle and station astronauts and cosmonauts continue the task of unpacking the Raffaello high-tech moving van. European Space Agency astronaut Umberto Guidoni is overseeing the unloading of the Italian-built logistics module.

Today's wakeup call to the crew was "Con te Partiro" ("With You I Will Go"), sung by Italian opera singer Andrea Bocelli. It was played for Guidoni who is from Italy.

Working at the Robotics Work Station in the Destiny Laboratory, Helms and Voss will use the new Canadarm2 to maneuver the pallet within reach of Endeavour's robotic arm under control of Hadfield and Parazynski. In a reverse passing of the torch, the new arm will pass the pallet to its older cousin officially beginning the station arm's own career in space.

Hadfield and Parazynksi completed connections on the station's new robotic arm during the second of two planned spacewalks yesterday. The 7 hour, 40 minute Extravehicular Activity included the connection of power, data and television cables, which allow the robot arm to operate from a base on the outside of the Destiny science laboratory.

At about 2:30 today, Endeavour's Commander Kent Rominger and Pilot Jeff Ashby will boost the station's altitude another 2 ½ miles by firing thruster jets in a precise sequence for about one hour. With one reboost maneuver completed several days ago, a third and final identical firing of the reaction control system jets is planned Thursday.

Both spacecraft are in excellent shape orbiting the Earth every 92 minutes at an altitude of 243 statute miles.

Shortly after the ISS crew went to bed last night, the ISS flight controllers reported a loss of Command and Control Computer number one (C&C 1), one of three systems management computers on board. Overnight, flight controllers inititiated a procedure to re-string those functions through one of the two remaining backup computers that route data for systems management. This morning when Expedition Two Flight Engineer Susan Helms sent commands to transfer data files from the mass storage device, which houses the files for station systems management for the operation of the robotic work stations, the command was rejected.

After initial troubleshooting efforts failed to resolve the problem, flight controllers once again worked a procedure to re-string data management functions to the third computer, but the computer problem continued and flight control teams continued to evaluate the situation throughout the day.

Following a power cycle of command and control computer 1, the first of a series of diagnostic commands - this to turn on and off a light on board the Destiny laboratory - was successfully transmitted from the ground to the space station shortly before 7:30 p.m. Overnight the space station flight control team will attempt to reset the computers by commanding them from the "primary" to "standby" mode in an effort to clear any software interaction that might be causing the problems. If successful, this would allow the Expedition Crew and ground controllers to again interface with the command and control computers. The diagnostic troubleshooting will continue through the night.

The primary result of today's computer problem was a loss of communication and data transfer between the Space Station Flight Control Room and the station. Communication capability was routed through Endeavour enabling the crew and flight controllers to talk to one another.

Despite the difficulties encountered with the computer system today, all systems on board the spacecraft continued to function properly.

Several of the activities planned for today, including the handoff of a 3,000 pound pallete from the station's new robotic arm, back to the shuttle's arm, were postponed until Thursday, pending resolution of the computer issue. A reboost of the complex, using Endeavour's small thrusters, also was delayed. The crew members instead turned their attention to offloading experiment racks and equipment from the Raffaello logistics module, and transferring the experiments and hardware to the station.

Once the computer difficulties are resolved, Helms and crew mate Jim Voss will command the station's new Canadarm2 to maneuver the pallet within reach of Endeavour's robotic arm under control of mission specialists Chris Hadfield and Scott Parazynski.

Shortly before 7 p.m. Central, Mission Control said goodnight to both crews following a busy day on orbit. Expedition Two Commander Yury Usachev, Voss and Helms are slated to wake up about 2:30 a.m. Thursday; the seven astronauts on board Endeavour will receive a wake-up call from Mission Control about 10 minutes later.

Space station flight controllers then sent commands that have put the station's systems in a better configuration in the event computer problems recur today. They also are planning to send commands that will transmit data to the ground from the station computers to allow technicians to thoroughly analyze those computers' hardware and software as part of the investigation that is under way to determine the cause of the computer problems.

Today's plan for the astronauts and cosmonauts aboard Endeavour and the station will have them continue joint work this morning to reload the Raffaello logistics module with unneeded station equipment and supplies for return to Earth. The crews have almost completed unloading the 4,000 pounds of equipment that Raffaello carried to the station. While that reloading work takes place, flight controllers will continue their analysis of the station computers.

Given continued success with the computer troubleshooting, the crews will resume work with the station's new Canadarm2 and the shuttle's robotic arm after 8 a.m., handing off a 3,000-pound Spacelab Pallet from the station arm to the shuttle arm to store the pallet back in Endeavour's payload bay. Another reboost of the spacecraft's altitude is planned later today as well, an hour-long jet firing by Endeavour that will raise the complex's altitude by almost 4½ miles.

A practice run with the new station arm to rehearse moves the arm must make during the next shuttle assembly mission to the station to attach a new airlock will be conducted on Friday.

The crew of Endeavour was awakened just after 2:40 a.m. by a Russian folk song, "Behind the Fog." That song was played for Endeavour crewmember Russian cosmonaut Yuri Lonchakov. The two spacecraft are orbiting the Earth every 92 minutes at an altitude of 243 statute miles.

Working at a laptop computer aboard the station that serves as the crew's primary interface with the station's United States command and control computer system, Helms relayed the good news about 3:45 a.m. Shortly afterward, Helms performed a series of troubleshooting steps that restored the ground's ability to monitor and send commands to the station's U.S. systems.

Space station flight controllers then sent commands that have put the station's systems in a better configuration in the event computer problems recur today. They also sent commands that transmitted data to the ground from the station computers to allow technicians to thoroughly analyze their hardware and software as part of the investigation that is under way to determine the cause of the computer problems.

Today, the astronauts and cosmonauts aboard Endeavour will continue joint work to reload the Raffaello Logistics Module with unneeded station equipment and supplies for return to Earth. The crews have completed unloading the 4,000 pounds of equipment that Raffaello carried to the station. While the reloading of Raffaello takes place, flight controllers will continue their analysis of the station computers. The station command and control computer brought on line early this morning has continued to be fully functional and operate normally throughout the day. Controllers are working to bring another such computer online as a backup system later today. The recovery of the one command and control computer during the night is believed to have resulted from an automatic sequence aboard the station that powered each of the three command and control computers on and off in an attempt to bring them on line. The other two computers remained off line, however.

Given continued success with the computer recovery, the shuttle and station crews will resume work with the station's new Canadarm2 and the shuttle's robotic arm on Friday, handing off a 3,000-pound Spacelab Pallet from the station arm to the shuttle arm to store the pallet back in Endeavour's payload bay. A practice run with the new station arm to rehearse moves the arm must make during the next shuttle assembly mission to the station to attach a new airlock also will be conducted on Friday.

A second reboost of the station's altitude remains planned for later today. It will be an hour-long jet firing by Endeavour that will raise the complex's altitude by almost 4½ miles. The two spacecraft are now orbiting the Earth every 92 minutes at an altitude of 243 statute miles.

Mission Specialist Scott Parazynski, at the controls of the shuttle's robotic arm and assisted by European Space Agency Astronaut Umberto Guidoni, grappled the 14,700 pound "moving van," undocking it from the Destiny laboratory and carefully maneuvering it into position before securing it in the payload bay. Over the course of the past week, the astronauts and cosmonauts on board the station transferred 6,000 pounds of equipment from Raffaello to the station, and then stowed unneeded equipment and hardware on board for return.

The unberthing of Raffaello followed last night's work by ground controllers to successfully synchronize timers on all the on-board computers, including the one operational Control and Command (C&C) computer in Destiny. With the one operational C&C computer, and Susan Helms at the ready with a back-up laptop computer in Unity, the crew was given a "go" to begin the undocking procedure about 2:20 p.m. today.

Work to recover the command and control computers continued throughout the day today, with good progress reported, and a reload of software currently under way to restore C&C computer number three to full performance. C&C computer number one was determined to have a failed hard drive. That C& C computer will be replaced on orbit with a backup payload computer, called Payload Computer Two, so that the failed C&C computer can be returned to Earth for inspection and analysis. Overnight, flight controllers will reload software on C&C number one in the hopes of bringing it back on line as well.

The plan for the crew tomorrow, assuming a minimum of two C&C computers are up and functioning, would see Helms and crew mate Jim Voss operating the station's robotic arm to hand off its cradle to the shuttle's robot arm, being commanded by Mission Specialists Scott Parazynski and Chris Hadfield on board Endeavour. Most of the activities planned for a "dress rehearsal" of the maneuvers the arm will perform during the next station assembly mission to install an airlock have been deleted from the timeline. Only the portions of the rehearsal related to shuttle robotic arm camera views will be performed.

Earlier today, NASA and the Russian Aviation and Space Agency, Rosaviakosmos, reached a decision on the launch of the Soyuz replacement vehicle, for 2:37 a.m. central time Saturday. Rosaviakosmos has agreed to delay the Soyuz docking to the station if additional time is required to resolve command and control problems aboard the station.

Mission managers will assess the need for that additional docked day of operations based on specific criteria, including a minimum of two fully functioning command and control computers, securing the Canadarm2 cradle pallet back in Endeavour's payload bay, successfully reloading software in Command and Control computer Three, and completing final transfer activities between the station and shuttle.

With another busy day behind them, the two crews were bid goodnight by Mission Control and will be awakened at 2:41 a.m. Saturday. Both spacecraft are in good condition, orbiting the Earth every 92 minutes.

The successful exchange of the pallet was the last remaining major objective of the mission to be accomplished and could pave the way for Endeavour to undock from the station Sunday morning, if computers on board can be placed in a stable configuration overnight. Mission managers had established three specific criteria to be met prior to Endeavour's undocking. The criteria were to reberth the cradle pallet in the shuttle's payload bay, complete final transfer activities and place the station's command and control (C&C) computers in a stable configuration.

With the pallet securely in Endeavour's payload bay and all final transfer items in place, the one remaining item is to ensure the computer system is in a stable configuration prior to Endeavour's departure. Overnight, flight controllers will uplink a series of commands designed to restore the two computers to full capability. C&C three is in an acceptable condition, although it is known to have a bad hard drive. Helms and crew mate Jim Voss will perform repair work on that computer at a later date.

A final decision whether to undock Endeavour - and delay the docking of the Soyuz replacement vehicle - is expected late tonight or early Sunday morning.

After spending much of this morning refining procedures to minimize inputs to the station's primary command and control computer, which developed problems accessing its hard drive, Space Station Flight Director Mark Ferring gave the Expedition Two crew a "go" to begin with arm operations at 1:27 p.m. With Helms working at the robotic work station, first motion of the station arm occurred at 3:01 p.m. Through a series of carefully choreographed commands, the station arm was maneuvered into its handoff position. Hadfield then slowly moved Endeavour's 50-foot long robot arm into position to latch onto the cradle, which was securely attached to the station arm at 3:43 p.m. At 4:02 p.m., as the two spacecraft flew over British Columbia, the pallet changed hands.

Both arms then began backing away - with the station arm now under command of Voss, according to plan. Hadfield then stowed the pallet in Endeavour's payload bay at 4:51 p.m.

Earlier in the day, Voss informed flight controllers that Endeavour crew members were helping with maintenance activities on the station's treadmill, called TVIS, installing new hardware to allow the Expedition crew to once again use it for exercise. The treadmill's walking surface had degraded and the crew had been told not to use it until repairs were made. Voss reports repairs are now about 50 per cent complete.

After enjoying a meal together, both crews were scheduled to go to sleep shortly after 7 p.m. Both crews will enjoy an extra hour of sleep, waking up just before 4 a.m.

Due to a compressed schedule tomorrow, the in-flight crew news conference, originally scheduled for 6:15 a.m. Sunday, has been canceled.

If a decision is made to undock tomorrow, the astronauts and cosmonauts will exchange final farewells about 9:30 a.m. and then begin closing the hatches between the two spacecraft. Undocking would occur at 12:34 p.m. central. Pilot Jeff Ashby would then slowly back Endeavour away to a distance of approximately 450 feet, where he will begin a three-quarter circle flyaround of the station before commanding a final separation burn signaling Endeavour's final departure from the station. With an undocking Sunday, the mission is scheduled to conclude with a landing at the Kennedy Space Center at 8:04 a.m. Central time Tuesday.

As Pilot Jeff Ashby slowly backed Endeavour away, Commander Kent Rominger and Expedition Two flight engineer Susan Helms exchanged final wishes for Endeavour's planned return to Earth, and a continued safe journey for the station crew. Once Endeavour was at a distance of 450 feet from the station, Ashby initiated a three-quarter circle flyaround of the station as Mission Specialist Yuri Lonchakov activated a large-format IMAX camera in Endeavour's payload bay to photograph the station.

At 1:28 p.m., with the flyaround complete, Ashby fired a separation burn, initiating Endeavour's final departure from the orbiting complex, now equipped with a new Canadian-built robotic arm and communications antenna, installed by Mission Specialists Scott Parazynski and Chris Hadfield during two space walks. During eight days of joint operations, the two crews also transferred more than three tons of supplies, equipment and scientific experiments to the station.

On board the station, the Expedition Two crew - Commander Yury Usachev and Flight Engineers Jim Voss and Helms - will enjoy some time off this afternoon following a busy week on orbit. Early Monday morning, they will support the docking of a replacement Soyuz spacecraft that will serve as the station's "lifeboat." The Soyuz and its crew of three - Commander Talgat Musabayev, Flight Engineer Yuri Baturin and American businessman Dennis Tito -- is scheduled to dock at 2:52 a.m. Monday.

Endeavour's crew will go to sleep shortly after 4:30 p.m. today, awakening at 1:41 a.m. Monday to begin what should be their final full day on orbit. Endeavour is scheduled to return to the Kennedy Space Center, weather permitting, at 8:03 a.m. Tuesday. The primary activity for the crew on Monday will center on Endeavour's return to Earth, with Rominger, Ashby and Flight Engineer John Phillips verifying the performance of Endeavour's flight control surfaces and steering jets. Hadfield, Parazynski, Lonchakov and Umberto Guidoni will begin stowing away much of the equipment the crew has used over the past 11 days on orbit. All seven crew members are scheduled to participate in a press conference, talking with media in the U.S., Canada and Italy, at 10:01 a.m. Monday.

The Soyuz has a lifetime on orbit of about six months. The crew of the Soyuz which docked today, commander Talgat Musabayev, Flight Engineer Yuri Baturin and American businessman Dennis Tito, will return to Earth aboard the Soyuz capsule that launched the Expedition One crew to the station last Oct. 31. That Soyuz has been at the station since it docked there Nov. 2.

When this morning's docking occurred, the shuttle Endeavour was about 78 statute miles ahead of the space station. Its seven crewmembers will spend today preparing for its return to Earth. Landing is scheduled for 8:04 a.m. CDT Tuesday at Kennedy Space Center in Florida. Endeavour crewmembers were awakened at 12:41 a.m. by music from the soundtrack of the movie Gladiator.

Today, shuttle Commander Kent Rominger, Pilot Jeff Ashby and Flight Engineer John Phillips will test Endeavour's flight control surfaces and steering jets. Canadian astronaut Chris Hadfield, mission specialist Scott Parazynski, cosmonaut Yuri Lonchakov and European Space Agency astronaut Umberto Guidoni will stow away much of the equipment the crew has used over the past 11 days in space. All seven crewmembers are also scheduled to participate in a press conference with media in the U.S., Canada and Italy at 10:01 a.m.

Endeavour accomplished all of its major mission goals during the eight days it was docked to the space station. Parazynski and Hadfield installed and helped test a new Canadian-built robotic arm on the space station during two spacewalks that lasted a total of 14 hours and 50 minutes. Hadfield made history on that first space walk by becoming the first Canadian astronaut to ever walk in space. Working with the station's Expedition Two crew, Russian Commander Yury Usachev and astronauts Jim Voss and Susan Helms, they transferred more than three tons of supplies, equipment and scientific experiments to the station, then repacked 1,600 pounds of equipment that was no longer needed aboard the station.

Space station flight controllers were successful overnight in reformatting the hard drive on new Command and Control (C&C) Computer One, which was originally a payload computer. Controllers then copied all the software from the prime C&C 2, to the C&C 1 hard drive. After more testing later today, the station's three C&Cs will have two hard drives that contain all the necessary software to run the station's systems.

The three command and control computers onboard have been recovered, for the most part, with C&C 2 being used as the primary and C&C 1 as backup. The third currently is in standby while work continues to fully load the hard drive on C&C 1 with identical software as that on the primary system. The computers began exhibiting problems last Wednesday during Endeavour's visit and flight controllers continue to reconfigure the systems to support all operations on board including the Robotic Work Station which will serve as the command post for complete checkout of the station's new robotic arm - Canadarm2 - delivered to the station on the STS-100 mission.

While investigations into what caused the computer problems onboard continues on the ground, science activities continue onboard. Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms are overseeing the activation of several experiment racks onboard, including one that is remotely operated from the ground. It is the first to be operated in this fashion.

Except for the Human Research Facility, all station payloads are overseen from NASA's Payloads Operations Center in Huntsville, Alabama.

The HRF is managed and operated by a team in the Telescience Support Center at the Johnson Space Center.

The Destiny Laboratory's carbon-dioxide removal system is operating at half its design capability, but still working in tandem with the Russian system to provide adequate CO2 removal capability for the six crew members.

The Soyuz Taxi Crew is scheduled to depart Saturday night at 9:19 p.m. CDT in the spacecraft in which the Expedition One crew arrived last November. The new Soyuz will remain docked to the station for the next six months serving as an emergency return vehicle should that become necessary.

In preparation for that Soyuz vehicle swap, a test firing of the oldest vehicle's thruster jets is scheduled in the next day or two to ensure it is ready to come home early Sunday morning. This test is similar to the Reaction Control System hotfire test on the shuttle before it returns home from a mission.

Beginning Thursday May 10, and occurring each Thursday thereafter leading to the next shuttle mission to the station, the crew will test the Canadian-built robot arm on the station. This will verify its operation before the next component - the U.S. airlock - arrives. The airlock can only be attached to the station using this new robot arm.

The International Space Station continues to orbit the Earth in good shape at an altitude of 245 statute miles (395 km).

Beginning at about 9 a.m. central time tomorrow (Thursday) and continuing each Thursday for the next six weeks, the Canadian-built Space Station Remote Manipulator System delivered on the most recent flight of the shuttle will be fully checked out in preparation for its first assembly assignment to install the station's airlock in June. Tomorrow's checkout will include cycling the capture device inside the arm's end effector and actually latching onto two different fixtures on the station: one on the Destiny Laboratory and one on the transfer tunnel between the lab and the Unity module.

Engineers on the ground have worked around the clock to restore full capability of the station's command and control computers since their mass storage devices exhibited failures in two of the three units during Endeavour's visit to the ISS last month. The computers - known as C&C (for command and control) 1, 2 and 3, act as the interface between station systems, the software and the hard drives that store and execute programs required for various activities, including the operation of the robot arm known as Canadarm2.

The current configuration shows C&C 2 as the primary computer, C&C 1 as a fully capable backup, and C&C 3 available as a standby without the use of a mass storage device. C&C 3's hard drive has exhibited the same potential failure characteristics as that of C&C 1. As a result, the crew built a spare computer this week and is ready to install it as a replacement for C&C 3, if needed.

Regardless, additional computer spare parts are being loaded aboard the next Progress supply vehicle scheduled for launch May 20 from the Baikonur Cosmodrome in Kazakhstan. It will dock May 22 to the back end of the Russian Zvezda module. The failed hard drive was returned aboard Endeavour May 1 and troubleshooting is ongoing as to what caused the failure.

With a new Soyuz vehicle now available at the ISS, Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms got back to work on board and set up for the robotics work that will utilize the Robotics Work Station in Destiny. They also completed repairs on the high-tech treadmill in Zvezda, restoring it to full use for the first time since it broke during the Expedition One mission.

Science activities continue onboard, scheduled during and around the robotics work and maintenance tasks.

The fourth Progress vehicle dedicated to station resupply is set to launch atop a Soyuz rocket at 5:33 p.m. Sunday from the Baikonur Cosmodrome in Kazakhstan. Docking to the back end of the Zvezda module is scheduled at approximately 7:20 p.m. next Tuesday. Commander Yury Usachev has checked out the station's manual docking system in the event the automatic docking procedure does not work.

While awaiting the arrival of the Progress carrying 3,100 pounds of supplies, including food, spare computer parts, and other logistical items, crewmembers Jim Voss and Susan Helms are preparing to continue the on-orbit checkout of the station's new robotic arm that will be used to install the station's airlock next month.

On the heels of last week's test of the robotic arm, known as Canadarm2, the station's remote manipulator system will be tested beginning about 5:30 Central Thursday morning.

Setting the stage for that test was the reconfiguration of the operational string of software from Prime to Redundant. This will allow a full checkout of the arm using this backup system in the event that the primary channels were to fail. The arm will be maneuvered through various positions, its end effector snares will be cycled and the video cameras will be checked.

Next Thursday, May 24, Helms will maneuver the arm through the exact movements as if the airlock was attached. This will serve as a "dry run" for what is planned during the removal from the shuttle's payload bay and the installation on the Unity module. The first set of testing a week ago verified the arm's functions in the primary mode culminating in the capture of a grapple fixture on the outside of Destiny. All of the arm operations are controlled via the station's command and control computers, which have been restored to full functionality.

The robotic arm checkout is scheduled every Thursday for the next five weeks to ensure it is healthy before Atlantis launches carrying the airlock.

Last Friday, the third C&C computer was swapped with a spare that was built out of existing computer components on board. It has since been loaded with software identical to the other two C&C computers. Working in the same area behind a rack in the laboratory, a blocked filter in a condensate dump line was changed allowing full operation of the water dump system. This repair precludes the need to transfer wastewater to 100-pound containers for disposal aboard the shuttle when it visits.

The failed hard drive was returned aboard Endeavour after the 6A mission and troubleshooting continues as to the cause of that failure in late April.

Presently, both U.S. solar arrays delivered on assembly flight 4A last November are locked in place while engineers evaluate higher than normal electrical currents on the motors that allow the arrays to track the Sun. The arrays continue to absorb plenty of solar energy to provide the required electrical power for station experiments, avionics and other components on board.

Science investigations continue onboard under the auspices of the Payload Operations Center at NASA's Marshall Space Flight Center in Huntsville, AL, except for the Human Research Facility, which is monitored and controlled from the Telescience Support Center (TSC) at the Johnson Space Center, Houston.

The International Space Station is operating in excellent shape at an altitude of 250 miles (401 km).

The Progress joins a Russian Soyuz craft that is linked to the earthward facing docking port of the Zarya module of the ISS, and paves the way for the arrival in three weeks of the Shuttle Atlantis with a five-person crew on the STS-104 mission to install the huge Joint Airlock to complete the second phase of the assembly of the station.

While awaiting the arrival of the Progress, Voss and Helms spent Monday operating the Canadian-built station robotic arm to gather additional data as to the cause of the intermittent problem seen during last week's checkout activities in the backup, or redundant string of arm software. The test yesterday repeated some of last week's tasks and the redundant system worked perfectly. While the arm work was underway, Usachev tested the automatic and manual docking systems on the station in preparation for the Progress vehicle's arrival.

The stage now is set for a complete "dry run" Thursday of the robotic arm movements required for installation of the Airlock. The station's robotic arm is the only means for attaching the Airlock on the Unity module since the shuttle's robot arm cannot reach the installation location. In preparation for that task, Thursday's checkout will mirror the movements planned in June as if the Airlock were attached to the arm. This test not only will validate the arm's operational capability, but also will be conducted on the redundant string of software and hardware. The primary string was tested nearly two weeks ago with no problems.

If this week's checkout is successful, Friday's meeting of the ISS Mission Management Team will reassess the need for replacement of one of the arm's computer units, which is mounted on the arm itself. If required, the change out of the Computer Unit would be added to a previously scheduled "internal" spacewalk June 8 to reposition a docking cone in the cylindrical transfer compartment of the Zvezda module which is linked to the Zarya module. That docking cone will serve as the target and initial contact point for the Russian Docking Compartment set to arrive at the station in late August or early September.

While on-orbit activities continue, Space Shuttle Atlantis is being readied for launch shortly after 3 p.m. Central time on June 14. The orbiter will be moved to its launch pad at the Kennedy Space Center next week.

The International Space Station is operating in excellent shape at an altitude of 250 miles (401 km).

With more time now needed to complete an analysis of the communications problems between the arm's shoulder pitch joint in its redundant or backup mode, and the arm's backup computer unit, Shuttle and Station program managers decided to postpone the launch of Atlantis on the STS-104 mission to deliver the Joint Airlock to the ISS until no earlier than early July. The next ISS assembly flight after that, STS-105 aboard Discovery, was also delayed until no earlier than early August to accommodate the Airlock mission and to allow managers to consider a replacement of the shoulder joint on the August flight during one of two spacewalks planned by Dan Barry and Patrick Forrester. No final decision on replacing the joint has yet been made.

The recently installed Canadarm2 has fully redundant computer control systems. All of the arm's joints are functioning perfectly through its primary channel, but the backup channel has run into a series of recent problems, including the unexpected activation of a switch for the arm's brakes earlier this month in the backup mode of operation during a test of the arm's wrist. That problem has not reoccurred in subsequent testing. The shoulder pitch joint problem cropped up last week during other arm checkouts when the joint experienced intermittent dropouts in communicating with the backup computer unit.

It had been hoped that a software patch developed by Canadian engineers who designed the arm would clear the communications dropouts, but it did not resolve the problem, resulting in the need for further testing and analysis. Robotics experts suspect that the problem resides in the shoulder pitch joint hardware, not the software or the computers associated with its operation. Expedition Two Flight Engineers Jim Voss and Susan Helms had hoped to perform a "dry run" of the Airlock installation procedures today, but that simulation was postponed.

The Canadarm2 is required for the grapple of the Airlock in Atlantis' cargo bay and its installation on the starboard docking port of the Unity module of the ISS. The 12 ½ ton Airlock will enable future Station spacewalks to be conducted in either U.S. or Russian spacesuits rather than from the Russian Zvezda module. The Shuttle robot arm cannot reach the Airlock installation location.

In the meantime, ISS managers will decide Friday whether to ask Voss and Expedition Commander Yury Usachev to add the replacement of the arm computer unit to a previously scheduled "internal" spacewalk in the Zvezda's spherical transfer compartment on June 8. That first ISS-based spacewalk is designed to reposition a docking mechanism in preparation for the arrival of a Russian docking module later this year. If approved, the computer replacement task would involve Usachev and Voss venturing outside the Station in Russian suits for their spacewalk before reentering Zvezda's docking compartment for the mechanism repositioning work.

Engineers are also assessing the performance of a motor on one of the two wings of the P6 solar array truss structure that enables the solar mast to track the sun as the ISS orbits the Earth. Although there is more than ample power being generated for all Station systems, the motor is generating higher than normal electrical currents and may need to be replaced on a subsequent Shuttle assembly flight.

Meanwhile, Usachev, Voss and Helms completed the unloading of an unmanned Russian Progress resupply vehicle which arrived at the ISS last week loaded with 3100 pounds of supplies, food, clothes and spare parts. A spare computer hard drive brought to the ISS on the Progress was installed in one of three central Station computers, bringing the outpost's computers back to full functionality.

Commander Yury Usachev and Flight Engineer Jim Voss will open hatches in the Zvezda module beginning Friday morning about 9:30 to reposition a docking mechanism in preparation for the arrival of a Russian docking module later this year. They climbed into their Russian spacesuits Tuesday, entered the transfer compartment and conducted a practice session for the task, which is budgeted to take about 30 to 40 minutes.

As a precaution, hatches will be closed at various locations on the station so that the small, ball-shaped transfer compartment can be depressurized. Flight Engineer Susan Helms will remain in the Zarya module throughout the Extravehicular Activity (EVA).

Meanwhile, the Canadian Space Agency today planned to send computer commands to the station's robot arm, called Canadarm2, to attempt to pinpoint the cause of a problem with one of its seven joints in the redundant, or backup mode. Though the primary system of the arm works perfectly, the arm must have a prime and backup operating system functioning prior to the launch of Atlantis delivering the Joint Airlock to the complex.

The Canadarm2 is required for the grapple of the airlock in Atlantis' cargo bay and its installation on a docking port of the Unity module. The 25,000-pound airlock will allow future station-based spacewalks to be conducted in U.S. and/or Russian spacesuits. The Shuttle robot arm cannot reach the Airlock installation location.

In parallel, a software patch is being developed that actually can mask, or inhibit, the use of the suspect shoulder pitch joint allowing operation of the arm in six of the seven degrees of freedom. Again, the arm works fine on its primary string and, in fact, yesterday was maneuvered to what likely will serve as its stowed, or cradled position, with each end firmly attached to a grappling pin on the outside of the Destiny laboratory and one on the tunnel adapter leading to Unity.

Until the Canadarm2 evaluation is completed at week's end, shuttle and station managers will not firmly decide on the launch dates for the next two assembly missions. However, at present the next flight is tentatively slated for launch in early July pending resolution of the shoulder pitch joint problem and the conduct of a "dry-run" of the airlock installation. The follow-on flight remains scheduled for early August carrying a replacement crew for Expedition Two.

The Expedition Three crew of Commander Frank Culbertson and Flight Engineers Vladimir Dezhurov and Mikhail Turin today completed training at Star City outside Moscow.

Usachev and Voss entered the small, spherical transfer compartment at the forward end of the Zvezda Service Module to begin the first spacewalk at the ISS without the presence of a shuttle. They removed a hatch at the bottom (Earth-facing part) of the compartment to open it to the vacuum of space and officially begin the spacewalk at 9:21 a.m.

After lashing the hatch cover to the top of the compartment, they replaced it with a docking cone assembly that had been temporarily stowed on a transfer compartment wall. Using a rotating handle, they secured it firmly with the twelve roller-like hatches around its perimeter at 9:40 a.m., marking the official end of the spacewalk. With help from fellow crewmember Susan Helms, who stayed in the Zarya module and helped coordinate the spacewalk, the activity went very quickly. The 19-minute spacewalk had been expected to take 30 to 40 minutes. The docking cone was installed to prepare for the arrival of the Russian docking compartment, scheduled for later this year.

Meanwhile, managers have postponed the launch of the Space Shuttle Atlantis on the STS-104 mission to no earlier than July 7. Atlantis will take the Joint Airlock to the ISS. The ISS's new Canadarm2 will be used to install the airlock, and engineers are continuing to troubleshoot an intermittent problem in the arm's secondary power and control string. They also continue to try to evaluate why brakes in the arm's wrist joint came on without being commanded during an earlier test run.

The STS-105 flight of Discovery, taking the Expedition Three crew to the ISS and returning the Expedition Two crew to Earth, will be launched no earlier than Aug. 5.

Friday marks 100 days in space for the three crewmembers, Commander Yury Usachev, and Flight Engineers Jim Voss and Susan Helms, since launch on March 8 to replace the Expedition One crew.

Meanwhile, plans are in place for a complete checkout of the station's robotic arm, called Canadarm2, on Thursday to check all of the positions through which it will be maneuvered to support the installation of the next pressurized component - the Joint Airlock - scheduled for launch aboard Space Shuttle Atlantis about July 12 from the Kennedy Space Center, FL.

The scheduled 4-hour checkout, set to begin about 10 a.m. Central time, effectively will serve two functions. First, the operation will verify the arm's ability to support the Airlock installation on the Unity module of the station. Second, to continue to investigate the reason for an intermittent loss of communication between the arm's shoulder pitch joint and its computer commanding unit. A diagnostic software patch has been loaded in the station's onboard computers to attempt to obtain additional data on the arm's operation.

Meanwhile, shuttle and station managers have elected to delay the rollout of Atlantis to the launch pad while the robotic arm troubleshooting continues. At present, the rollout is scheduled for Tuesday to support a launch around 4 a.m. Central on July 12. The option still exists to postpone the mission until September and fly Discovery to the station first on the STS-105 flight no earlier than August 5 to deliver the Expedition Three crew as a replacement for Expedition Two.

This week has been the busiest so far aboard the station for science investigations with more than 25 hours of experiment work budgeted for the crew.

The International Space Station is orbiting at an altitude of around 240 miles (385 km).

The decision to launch Atlantis in July came after several reviews in which teams of engineers from NASA, the Canadian Space Agency and its prime robotics contractor - MD Robotics - concluded that a communications error between the Canadarm2's shoulder pitch joint and the arm's main computer commanding unit was attributable to an intermittent problem with a computer chip in the joint's electronic system and not a problem with joint itself.

As a result, Canadian engineers are completing the development of a software patch to be uplinked to Canadarm2 which will "tell" the arm to ignore similar erroneous communications from the chip which might occur as the arm moves the Airlock from Atlantis' cargo bay for its installation onto the Unity module. The arm is, in reality, functioning perfectly in both its prime and redundant modes for all seven joints since the one and only communications dropout occurred several weeks ago in the shoulder pitch joint's redundant string of electronics.

Expedition Two Flight Engineers Jim Voss and Susan Helms are scheduled to complete a second dress rehearsal of the Airlock installation task Thursday using the arm in its prime mode. The arm performed perfectly in its backup mode last week during an initial dry run.

With the arm having been declared in good shape and ready to support Airlock installation operations, Shuttle Program managers ordered Atlantis to roll to Launch Pad 39-B at the Kennedy Space Center Thursday morning. The rollout today was postponed due to lightning in the area overnight. Managers will meet at KSC on June 28 in the traditional Flight Readiness Review to set a firm launch date for Atlantis.

Discovery, also in the Vehicle Assembly Building, remains on track to roll out to Launch Pad 39-A next week to support a launch no earlier than August 5 on the STS-105 mission to deliver the Expedition Three crew to the ISS and to bring food, clothing and logistical supplies to the outpost.

Expedition Two Commander Yury Usachev, Voss and Helms continued a variety of science investigations this with more than 17 hours of experiment work budgeted for the crew.

The International Space Station is orbiting at an altitude averaging 240 miles (385 km).

The face-to-face Flight Readiness Review at the Kennedy Space Center Thursday is expected to result in a launch target date for Atlantis at 4:04 a.m. CDT, July 12. Pending completion of the robotic arm checkout on orbit, Atlantis will arrive with the newest component of the station late in the evening of July 13. The Airlock is a critical component allowing Extravehicular Activity (EVA), or space walks to be conducted using U.S. spacesuits or Russian Orlan spacesuits without the presence of the shuttle.

The Airlock also will add an additional 1,200 cubic feet of volume to the station, bringing its size to about 12,000 cubic feet of volume. The six-and-a-half-ton module, built by Boeing at NASA's Marshall Space Flight Center, can only be attached to the station using the new Canadian-built robot arm that was delivered to the station on the most recent shuttle mission in April.

Since that time, the Canadarm2, as it's known, has been undergoing an extensive on-orbit checkout. Several problems with the testing led to launch delays, but those issues have been resolved and the arm has operated flawlessly for several weeks. In the event of a recurrence of the most serious of the problems, which was a communications error in the shoulder pitch joint's backup electronics, a software patch essentially telling the robotic arm's electronics to bypass the nuisance fault has been loaded into station computers, which likely will solve the problem should it surface again.

Extensive reviews by engineers from NASA, the Canadian Space Agency and its prime robotics contractor - MD Robotics - concluded that the communications error between Canadarm2's shoulder pitch joint and the arm's main computer commanding unit was attributable to an intermittent problem with a computer chip in the joint's electronic system and not a problem with joint itself.

Expedition Two Flight Engineers Jim Voss and Susan Helms will conduct an additional dress rehearsal of the Airlock installation task Thursday, following an identical run a week ago.

In preparation for launch, the STS-104 crew is at the Florida spaceport for its traditional countdown dress rehearsal that concludes Friday.

Expedition Two Commander Yury Usachev, Voss and Helms continued a variety of science investigations this week with more than 25 hours of experiment work budgeted for the crew.

The International Space Station is orbiting at an altitude averaging 240 miles (385 km).

The checkout of the Space Station Remote Manipulator System - Canadarm2 - continued this week with testing the positions and sequences that will be used for the installation of high pressure oxygen and nitrogen tanks on the outside of the Airlock after it is installed on the Unity module of the station.

Working from the Robotics Work Station inside the Destiny Laboratory, Flight Engineers Susan Helms and Jim Voss maneuvered the arm on its redundant, or backup, string of software to essentially qualify the arm for its first operational task scheduled to commence after Atlantis arrives late next week.

Atlantis' launch is scheduled for 4:04 a.m. Central time, July 12 with docking to the station late on the evening of July 13. Tucked in the shuttle's payload bay is the 6.5 ton Airlock that will add space walk capability to the orbiting outpost.

While Atlantis is being readied for next week's visit to the station, Discovery stands poised on the other shuttle launch pad ready to deliver the next resident crew to the station in August. Expedition Three will be commanded by veteran astronaut Frank Culbertson along with two Russian cosmonauts Vladimir Dezhurov and Mikhail Turin.

Expedition Two Commander Yury Usachev, Voss and Helms also continue to oversee a variety of science investigations.

The International Space Station (ISS) is orbiting in excellent shape at an altitude averaging 240 miles (385 km).

Atlantis Commander Steve Lindsey, Pilot Charlie Hobaugh and Mission Specialists Janet Kavandi, Jim Reilly and Mike Gernhardt will install an airlock named Quest on the station, increasing the orbiting complex's onboard capabilities for maintenance and construction and completing a major milestone in the station's orbital construction. The International Space Station crew - Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms -- was informed of Atlantis' launch just minutes after liftoff. The station crew spent the day preparing for the shuttle's visit. Earlier in the week the station crew performed final checks of the orbiting outpost's Canadian-built mechanical arm, an arm that will be used to attach the airlock, and reported the arm in excellent condition.

Atlantis is planned to dock with the station at about 9:51 p.m. Central on Friday. After opening Atlantis' payload bay doors and preparing the shuttle for an extended stay in space, Atlantis' crew will go to sleep at 9:04 a.m. Central today. The space station crew, now in its fourth month aboard the complex, will begin its sleep period at about 5:30 a.m. Central.

The station crew will awaken at 2 p.m. and Atlantis' crew will awaken at 5:03 p.m. today. When they awaken this afternoon, the shuttle crewmembers will spend their first full day in space checking out equipment in preparation for the major events to come on their 11-day mission: Friday's docking with the station and three space walks, the first to begin on Saturday, to install the new airlock.

Atlantis Commander Steve Lindsey, Pilot Charlie Hobaugh and Mission Specialists Janet Kavandi, Jim Reilly and Mike Gernhardt will spend their first full day in space checking equipment in preparation for the major events to come on their 11-day mission: Friday's docking with the station and Saturday's first of three space walks.

With Gernhardt and Reilly assisting during a seven-hour space walk, scheduled to begin around 9 p.m. Saturday, Flight Engineer Susan Helms will use the station's new robotic arm -- Canadarm2 -- to remove the Quest airlock from the shuttle's payload bay and attach it to the right side of the station's Unity connecting module. The new airlock will enable station crews to perform space walks in U.S. space suits without the shuttle being present. This ability will enhance the station's capabilities for maintenance and construction and complete a major milestone in the station's orbital construction.

The International Space Station crew - Commander Yury Usachev and Flight Engineers Helms and Jim Voss - awoke at 2 p.m. The station crew will spend its day preparing for the Friday docking of Atlantis and the Saturday installation of the Quest airlock. The Expedition Two crew has been in space since March 8 and in charge of the space station since it took over from the Expedition One crew March 18.

Commander Steve Lindsey and Pilot Charlie Hobaugh fired Atlantis' steering jets periodically during the night to adjust the shuttle's course toward the station. Atlantis now is trailing the International Space Station by about 1,800 statute miles, closing the gap by 230 miles with each orbit of Earth, on track to dock with the complex at about 9:53 p.m. Central. Astronauts Mike Gernhardt and Jim Reilly powered up and tested the two space suits they will wear during the three space walks planned to install the Airlock Quest on the station after Atlantis arrives. Assisted by Hobaugh, they also checked a third, spare suit that will be left aboard the station.

During the suit checks, the crew noted a white substance in the vicinity of the spare space suit's battery. Mission Control instructed the crew to take several standard precautionary measures, such as donning rubber gloves and turning off several ventilation fans, as they cleaned the substance off of the suit, swapped the suspect battery with a fresh one and changed the carbon dioxide removal cartridge. The old battery was then stowed away, sealed in leak-proof bags. The substance did no damage to the space suit and it remains in excellent operating condition.

Mission Specialist Janet Kavandi powered up Atlantis' robotic arm, successfully checking its operation and surveying the Quest airlock in the shuttle cargo bay using television cameras on the arm. The shuttle's robotic arm will be used to maneuver the space walkers during their planned work outside Atlantis and the station. The crew also powered up the shuttle's docking mechanism, preparing it for the linkup tonight.

Atlantis is in an orbit with a high point of 235 miles and a low point of 182 miles, circling Earth every 90 minutes. All of the shuttle's systems are in excellent condition.

Aboard the International Space Station, Expedition Two crew Commander Yury Usachev, and Flight Engineers Jim Voss and Susan Helms reviewed the schedule for Atlantis' arrival later tonight. The shuttle and station crews will go to sleep at about 8:04 a.m. The shuttle crew will awaken at 3:04 p.m. and the station crew at 4:04 p.m. to begin the rendezvous and docking activities.

The day's rendezvous operations began at 4:34 p.m. with Atlantis trailing the station by about 250 statute miles and closing the gap by 230 miles every orbit. Yesterday, the crew powered up the shuttle's docking mechanism and installed a centerline camera that will help line up the orbiter's docking mechanism with the station's docking port.

Aboard the International Space Station, Expedition Two crew Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms awoke at 4 p.m. The Expedition Two crew spent its orbital morning preparing the station for the arrival of Atlantis, and some initial cargo exchanges.

Another successful firing of Atlantis' orbital maneuvering system engines at 6 p.m. refined the shuttle's approach. A final burn, called the Terminal Intercept (Ti) burn, is scheduled for 7:33 p.m. when Atlantis is about 50,000 feet behind the station. After the Ti burn, the shuttle's rendezvous radar system will begin tracking the station and providing range and closing rate information to Commander Steve Lindsey and Pilot Charlie Hobaugh. When Atlantis reaches a point about a half mile below the station, Lindsey will take manual control of the shuttle and slow Atlantis' approach, flying to a point about 600 feet below the station. Mission Specialists Michael Gernhardt, Janet Kavandi and Jim Reilly will assist, operating additional range-finding tools and documenting the approach with an IMAX camera mounted in the cargo bay. Lindsey will trace a quarter-circle around the station, bringing the shuttle to a point a little more than 300 feet in front of the Destiny laboratory and Pressurized Mating Adapter 2. From that point, Lindsey will move Atlantis toward the station at a speed of one tenth of a mile per hour until the two vehicles are just 30 feet apart; there he will pause for a few minutes to check his alignment. Lindsey will gently close the distance until the shuttle's spring-loaded docking mechanism makes contact with the station. The mechanism will be retracted and latches commanded to close, completing the docking process.

After docking, the crews are scheduled to open the hatches between the two vehicles about 11:30 p.m. and greet one another in a brief welcoming ceremony.

The Shuttle crew's day began at 4:04 p.m. with a wake-up call from Mission Control, playing the song "Space Cowboy" by N'Sync for Mission Specialist Janet Kavandi. On board the Space Station, Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms also awoke at 4:04 p.m.

During tonight's space walk, Gernhardt, designated EV1, will be identifiable by the red stripes around the legs of his spacesuit, while Reilly, EV2, will be wearing an all-white space suit. Atlantis' pilot Charlie Hobaugh will coordinate the space walk from within the shuttle cabin.

Gernhardt will begin the space walk by removing an insulating cover, nicknamed the "shower cap," from the airlock's berthing mechanism, as well as protective covers from the mechanism's seals. Reilly will work to install bars on the airlock that will be used to attach four High-Pressure Gas Tanks during two subsequent space walks later in the mission. Gernhardt will then disconnect heater cables that kept the airlock warm while in the payload bay, which Reilly will stow along with the shower cap and berthing mechanism covers.

When the airlock is ready for installation, Helms, from a control panel in the station and assisted by crewmate Voss, will attach the Canadarm2 to the Quest airlock and lift it out of Atlantis' payload bay. Grappling of the airlock by the station's robotic arm is scheduled to occur at 11:04 p.m., with removal of the airlock from the payload bay at 11:19 p.m. The airlock is scheduled to be attached to the right side of the Unity module at 2:04 a.m.

Throughout the space walk, Atlantis astronaut Janet Kavandi will operate the shuttle's robotic arm, using it to maneuver the two space walkers around the space station and to provide camera views to assist Helms and Voss with their work.

Atlantis brings a new airlock to the station. It will enable station crewmembers to conduct spacewalks from the station, using either Russian or U.S. spacesuits.

The hatch separating the Atlantis crew, Lindsey, Pilot Charles Hobaugh, and mission specialists Mike Gernhardt, Janet Kavandi and James Reilly, from Expedition Two crewmembers Yury Usachev, Jim Voss and Susan Helms was opened at midnight. After a safety briefing by Expedition Two Commander Usachev, both crews began an hour-long review of procedures for the first of three spacewalks of the STS-104 mission.

The spacewalk, by Gernhardt and Reilly, is to begin about 9:10 p.m. Saturday and last more than seven hours. Focus of the spacewalk is the berthing of the airlock, named Quest. Two subsequent spacewalks by Gernhardt and Reilly will attach high-pressure Oxygen and Nitrogen tanks to the airlock.

After the hour-long meeting on the spacewalk, robotic arms on both the station and Atlantis were put through a rehearsal of procedures to be used during removal of the airlock from the shuttle's cargo bay and its attachment to the station. Helms took the station's 58-foot-long robotic arm, Canadarm2, through a dry run of the berthing of the new airlock to the starboard docking port of the station's Unity node. Aboard Atlantis, Kavandi powered up the shuttle's robotic arm and practiced its spacewalk activities.

Early Saturday Gernhardt and Reilly checked the batteries of their spacesuits and found no evidence of potassium hydroxide leakage that was seen Friday as they checked a spare spacesuit. The battery was replaced and the suit cleaned. Managers decided to postpone temporarily the planned transfer of that suit to the station while they study the situation.

Hatches between Atlantis and the station were closed at 4:45 a.m. and the pressure in the shuttle's cabin reduced to 10.2 pounds per square inch in preparation for the first spacewalk.

Today's work will include testing nitrogen and oxygen lines that will be used during future shuttle missions to replenish the airlock's tanks of high-pressure oxygen and nitrogen; testing the airlock's space walk equipment; and installing valves that will connect Quest to the station's environmental control system. In addition to checking and activating Quest's systems, the crews will remove the motor controllers from the airlock's berthing mechanism, which are no longer needed now that the airlock is firmly attached to the station.

The shuttle crew's day began at 4:04 p.m. with a wake-up call from Mission Control playing the song "No Woman No Cry" by Bob Marley for Mission Specialist Mike Gernhardt. On board the space station, Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms awoke at 5:04 p.m.

After the airlock was attached to the station early Sunday morning, and the first part of its checkout was completed, the shuttle and station crews held a ribbon cutting for the new addition. Station Commander Yury Usachev and Atlantis Commander Steve Lindsey cut a white ribbon that had been strung across the entrance of Quest's crew lock. Lindsey and Usachev made two cuts to the ribbon, each on either side of the word Quest to christen the new compartment. This evening's checkout of Quest will help prepare for the mission's third space walk, scheduled for Thursday evening. That space walk, during which two air tanks will be installed on Quest, will be the first to originate from the new airlock.

Yesterday, a decision was made to bring home a spare space suit aboard Atlantis that had experienced a leaking battery. Controllers were worried that the leaking battery may have damaged portions of the suit and decided to bring the suit home for inspection and cleaning. The originial plan had been to leave the suit aboard the station for use by future crews.

All systems continue to function normally aboard both the Space Shuttle Atlantis and the International Space Station. Later this evening, a little after 8 p.m., the shuttle's engines will be used to perform an hour-long reboost of the station's altitude.

Station Expedition Two crewmember Susan Helms lifted the airlock from the cargo bay of Atlantis using the station's Canadarm2 at 12:10 a.m. CDT. After a slow and carefully planned series of maneuvers with the arm, the airlock was maneuvered to the berthing port on the station's Unity node.

Spacewalkers Mike Gernhardt and Jim Reilly observed the berthing procedure from above and below, providing additional guidance for Helms. The airlock was berthed to the station at 2:40 a.m. Gernhardt then attached cables from the station to its new airlock to provide heating for Quest while Reilly pre-positioned foot restraints for the second spacewalk scheduled for Tuesday.

The spacewalk, coordinated by Atlantis' pilot Charlie Hobaugh in the shuttle's cabin, began at 10:10 p.m. Saturday with the shuttle and the station 237 statute miles above the South Pacific east of New Zealand. After moving into the cargo bay, Gernhardt removed an insulating cover, called the "shower cap," from the airlock's berthing mechanism and other covers from its seals. Reilly installed bars on the 6½-ton airlock which will serve as attachment points for four high-pressure tanks, two oxygen and two nitrogen. The tanks will be installed during the two subsequent spacewalks. The mission's third and final spacewalk will be conducted from the new airlock itself.

After the airlock was securely attached and after installation of the cable to power its heaters, Gernhardt and Reilly returned to the shuttle's airlock after flight controllers confirmed that the airlock's heaters were functioning.

Official end of the spacewalk occurred with repressurization of Atlantis' airlock at 4:09 a.m. today. The spacewalk lasted 5 hours and 59 minutes.

Later, Expedition Two crewmembers Yury Usachev, Jim Voss and Helms opened the hatch to the airlock vestibule, the small area between the station and Quest's largest compartment, and began its outfitting.

Mission Specialist Janet Kavandi will assist Expedition Two Flight Engineer Jim Voss in troubleshooting the suspected leak in an Intermodule Ventilation (IMV) assembly. The IMV Assembly, a series of fans and valves that circulate air between station modules, connects the Quest airlock to the station's environmental control and life support system. The two astronauts will examine the valve seals for any debris or damage and determine if the valve will have to be replaced. Should replacement be necessary, a spare valve is available aboard the station.

Meanwhile, Atlantis Commander Steve Lindsey and Expedition Two Flight Engineer Susan Helms will test oxygen lines between the station and the airlock. The lines will be used during future shuttle missions to replenish the airlock's high-pressure oxygen tanks with shuttle-supplied oxygen.

The Atlantis crew was awakened for its sixth day in space at 4:19 p.m. today by the song "Nobody Does it Better" performed by Carly Simon, played by Mission Control for Mission Specialist Jim Reilly. The International Space Station crew of Commander Yury Usachev, Voss and Helms is in its 131st day in space.

Atlantis' space walkers Mike Gernhardt and Jim Reilly will spend today preparing for their two remaining space walks. They will review plans and set up equipment in both Atlantis' airlock and the station airlock. The second spacewalk, to begin Tuesday evening, will originate from Atlantis while the third spacewalk, to begin Thursday, will be the first to originate from the station's new Quest airlock. Both of the remaining space walks will focus on the installation of high-pressure oxygen and nitrogen tanks on the exterior of the Quest airlock.

Lindsey, Atlantis' Pilot Charlie Hobaugh and Usachev will take a break from their work at 11:34 p.m. CDT for a 20-minute interview by news reporters from CBS, Space.com and KNBC-TV of Los Angeles.

After cleaning up about half a liter of water that spilled from a coolant line and getting rid of some air bubbles that caused the spill, the two crews installed valves that connect Quest to the station's environmental control system and a computer that will be used to run the airlock's systems. They also tested lines that will be used during future shuttle missions to replenish oxygen and nitrogen supplies, and removed bolt drivers from the airlock's berthing port, which are no longer needed now that the airlock is permanently attached to the station.

The extra time it took to get the coolant line working put the crews about an hour behind schedule, so a planned checkout of the airlock's space walk equipment was put off to another day. Station Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms were able to try out the airlock's audio communication systems, making the first radio calls to the ground from the airlock and two American space suits.

STS-104 Commander Steve Lindsey and Pilot Charlie Hobaugh fired the shuttle's engines for an hour Sunday night to boost the station to an altitude of 238 by 235 statute miles (383 by 375 kilometers). Mission Specialists Michael Gernhardt, Janet Kavandi and Jim Reilly also worked on equipment and supply transfers between the shuttle and station.

Gernhardt and Reilly made preparations for the second spacewalk of the mission, during which they will help install the first set of the High-Pressure Gas Tanks -- one oxygen tank and one nitrogen tank -- onto the airlock's shell on Tuesday. A third space walk, scheduled for Thursday evening, will see Gernhardt and Reilly use the new airlock for the first time.

The two crews will go to bed at 8:04 a.m., with a wake-up call scheduled for 4:04 p.m.

Early this morning, mission managers decided to add an additional docked day to the flight between the second and third spacewalks. The mission's third spacewalk, which will be the first out of the Quest airlock, will now occur Friday evening on Flight Day 10 instead of Thursday evening.

The two crews are about half a day behind schedule due to a small water leak that occurred when the astronauts were linking the new airlock to the station's Moderate Temperature Loop. The crews also have been troubleshooting a leaky air valve in an Intermodule Ventilation (IMV) Assembly in the rear, right side of the station's Unity node. Troubleshooting efforts to pinpoint where the valve is leaking and why will continue tomorrow and for now the astronauts have installed a cap on the valve to stop the leak. Should replacement of the valve become necessary, several identical valves are available aboard the station.

The Atlantis crew was awakened at 4:08 p.m. by "Happy Birthday Darlin'" sung by Conway Twitty. It was played for Atlantis Mission Specialist Janet Kavandi who is celebrating a birthday today as she soars 235 miles above the Earth.

During tonight's spacewalk, Expedition Two Flight Engineers Susan Helms and Jim Voss, working from a robotics workstation in the station's Destiny lab, will maneuver the station's robotic arm, the Canadarm2, over Atlantis' payload bay and grapple oxygen tank one. They will then maneuver the tank to Quest where the tank will be attached to the airlock by Gernhardt and Reilly. During the spacewalk, Gernhardt, wearing the spacesuit with the red stripes on the legs, will be on the end of the shuttle robotic arm, which will be controlled by Kavandi. Pilot Charlie Hobaugh will coordinate the spacewalk from inside Atlantis. The procedure will be repeated for nitrogen tank four. The remaining two tanks will be removed from Atlantis' payload bay Friday evening during the mission's third spacewalk.

Four of the arms belonged to space walkers Mike Gernhardt and Jim Reilly. Two robotic arms also were called into service - the shuttle's Canadarm and its big brother, the station's Canadarm2. Station Flight Engineers Susan Helms and Jim Voss were at the station arm's controls, while Mission Specialist Janet Kavandi guided the shuttle limb.

The space walk got off to a slightly delayed start at 10:04 p.m. CDT Tuesday after the station's primary Command and Control computer had to be restarted. The computer, needed to guide the station arm as it lifted the high-pressure oxygen and nitrogen tanks out of the shuttle cargo bay and into position alongside the new airlock, was back in business shortly after 8 p.m., allowing first motion of the arm by 9 p.m.

Gernhardt and Reilly, supported by their six colleagues inside the shuttle and station, latched the first two dog house-shaped tank assemblies into place without difficulty, so shuttle and station Flight Directors Paul Hill and Mark Kirasich decided to move ahead with installation of the third tank at 1:41 a.m.

The second space walk of the mission concluded at 4:33 a.m. CDT Wednesday. It was the 66th space walk in shuttle program history, and the 23rd devoted to International Space Station assembly. So far, STS-104 space walks have lasted 12 hours, 28 minutes.

The crews will have an extra day to prepare for the third and final planned space walk of the flight, which now is scheduled for Friday. Mission managers decided Tuesday to add the additional docked day to give the joint crew adequate time to ready the new airlock for its first use.

The two crews are about half a day behind schedule due to a small water leak that occurred when the astronauts were linking the new airlock to the station's Moderate Temperature Loop. The crews will resume troubleshooting a leaky air valve in an Intermodule Ventilation (IMV) unit on the rear, right side of the station's Unity node after wakeup scheduled for 4:04 p.m. today.

With the space walk complete, STS-104 Commander Steve Lindsey and Pilot Charlie Hobaugh, who also was the inside coordinator for the space walk, began another hour-long series of automated steering jet firings to reboost the station's altitude.

Atlantis Commander Steve Lindsey and Expedition Two Flight Engineer Jim Voss will do the valve replacement. It will be tested for several hours to ensure it is not leaking. Atlantis spacewalkers Mike Gernhardt and Reilly, assisted by Pilot Charlie Hobaugh will continue testing equipment of the new airlock Quest. The three astronauts also will transfer equipment to Quest for the third spacewalk of the mission. That spacewalk is scheduled for Friday evening and will be the first out of the new airlock.

Atlantis Mission Specialist Janet Kavandi and Expedition Two Flight Engineers Jim Voss and Susan Helms will install the Hatch between Quest's Crew Lock and Equipment Lock. The hatch is currently in its launch position at the interface between the airlock and the Unity node. After the hatch is installed in its new position, it will be tested for leaks for more than eight hours.

Station Commander Yury Usachev will spend his day working with one of the station's payload computers, performing periodic maintenance on several of the station's Russian systems and helping fellow crewmate Voss replace valves on the Airlock to continue linking the new module with the station's life support systems.

At about 2:30 a.m. Thursday, Lindsey will fire Atlantis' engines in a series of pulses during a one-hour period to boost the station's altitude. This will be the third and final reboost scheduled for this mission.

The Atlantis crew was awakened at 4:04 p.m. Wednesday by Sheryl Crow's "All I Wanna Do." The song was played for the entire crew from their training team.

Atlantis Commander Steve Lindsey and Mission Specialist Janet Kavandi will assist with the final checks of the airlock later in the morning. Subsequently, all eight crewmembers will gather to review the procedures for Friday's spacewalk, the third of the mission. During that spacewalk, Gernhardt and Reilly will attach the final nitrogen gas tank to the airlock, assisted by Voss and Expedition Two Flight Engineer Susan Helms who will be operating the station's robotic arm. At 10:11 p.m., the two crews will participate in a joint news conference with media representatives at several NASA centers and the Russian Mission Control Center in Korolev. That conference will run for 26 minutes and will be shown live on NASA TV. In addition, Lindsey is scheduled to downlink a tour of the Quest airlock around 3 a.m.

Station Commander Yury Usachev will perform various periodic maintenance duties on the station's Russian systems, as well as help fellow crewmates Voss and Helms prepare for robotics operations related to Friday evening's spacewalk.

The Atlantis crew was awakened at 4:04 p.m. by the song "A Time To Dance" by Janet Giroux played by the Space Center Intermediate School Symphonic Band. The band was directed by Giroux and the song was played for Reilly.

That space walk is scheduled to begin about 10:30 p.m. Friday, pending a successful leak check of the crew lock while the crew sleeps today. Mission Specialists Mike Gernhardt and Jim Reilly will attach a fourth and final supply tank to the airlock's exterior, and move on to some get-ahead tasks made possible when they were able to attach a bonus third tank during Wednesday's space walk. Tasks added to Friday's space walk include an inspection of one of the station's solar array swivels and inspection of the Floating Potential Probe that measures plasma levels around the solar arrays.

STS-104 Commander Steve Lindsey and Expedition Two Flight Engineer Jim Voss finished replacing the Intermodule Ventilation (IMV) Assembly valve in the station's Unity module about 7:30 p.m. Wednesday. With help from station Commander Yury Usachev, they replaced the leaking valve with another from the Destiny laboratory that won't be needed until the station's second node arrives in 2003.

Voss, Mission Specialist Janet Kavandi and Susan Helms moved the hatch from its initial location between the Unity module and the airlock's Equipment Lock to between the Equipment Lock and Crew Lock. The Equipment Lock will be used for storing and servicing space suits, while the Crew Lock will serve as the exit to space.

Usachev also worked with one of the station's payload computers, performing maintenance on several of the station's Russian systems, and Kavandi, Gernhardt and Reilly worked to transfer items between the shuttle and station while getting equipment and space suits squared away in the airlock. Helms also changed out a Command and Control computer that had been temporarily installed in place of a payload data computer in Destiny. The payload computer was cannibalized during the STS-100 mission and retasked when all three of the station's command computers broke down. The old computer will be returned to Earth on Atlantis for testing and analysis.

Lindsey and Pilot Charlie Hobaugh gave the station another boost using the shuttle's reaction control system jets, increasing the station's orbit about 5 miles to 244 x 240 statute miles. It was the final reboost planned for this mission. Atlantis will leave the station later this week about 10 miles higher than when it arrived.

During the mission's third spacewalk, Gernhardt and Reilly will install a second nitrogen tank on the Quest airlock. Three other tanks, two oxygen and one nitrogen, were installed during a previous spacewalk. Expedition Two Flight Engineer Jim Voss, assisted by Flight Engineer Susan Helms, will lift the final gas tank from the payload bay of Atlantis around 10:40 p.m. and slowly deliver it to Gernhardt and Reilly, who will be awaiting its arrival at the Quest airlock.

Atlantis Pilot Charlie Hobaugh assisted by Station Commander Yury Usachev will coordinate the nearly five-hour spacewalk. Commander Steve Lindsey will operate the shuttle's robotic arm.

The Atlantis crew was awakened at 4:04 p.m. by the song "I Could Write A Book" from the motion picture When Harry Met Sally. The song was played for Lindsey. All systems aboard both Atlantis and the International Space Station continue to function normally as the two spacecraft orbit the Earth at an average altitude of 240 statute miles.

STS-104 Commander Steve Lindsey, Pilot Charlie Hobaugh and Mission Specialists Mike Gernhardt, Janet Kavandi and Jim Reilly also got together with Expedition Two Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss in Quest to answer questions from reporters in the U.S. and Russia.

Voss reported tracking down and sealing a minor leak discovered during an overnight pressure check. Air had found a path from the Equipment Lock segment of the new airlock to its Crew Lock, which is the segment the orbital construction workers will open to the vacuum of space when they step outside about 11:09 p.m. CDT Friday.

Flight Directors Paul Hill and Mark Kirasich talked with the crew about 1 a.m. Friday, going over the final details and sending up the good news that both the shuttle and station flight control teams agree all systems are "go" for the first station-based excursion out of the airlock. Lindsey sent down a video tour of the fully outfitted Quest module about 4:50 a.m.

The entire crew then reviewed the plan for Friday's five-hour space walk by Gernhardt and Reilly. On their third foray outside this mission, the pair will attach the final nitrogen gas tank to the airlock and climb to the top of the station's solar array truss to check on a swivel joint that allows the arrays to track the sun. If time allows, they'll also take a look at the nearby Floating Potential Probe that measures the plasma created as the arrays drag through the rarified atomic oxygen at 240 miles up.

Meanwhile, Usachev performed some periodic maintenance duties on the station's Russian systems, and helped Voss and Helms prepare for their work with the Canadarm2 robotic arm's operations related to Friday evening's space walk.

After some time off to rest up after a very busy week, the crews were scheduled to turn in at 8 a.m. Their alarm clock is scheduled to go off at 4:04 p.m.

The Atlantis crew, Commander Steve Lindsey, Hobaugh and Mission Specialists Janet Kavandi, Mike Gernhardt and Jim Reilly, will leave behind the Expedition Two crew of Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms, who are in their 136th day in space.

The Expedition Three crew, Commander Frank Culbertson and Flight Engineers Vladimir Dezhurov and Mikail Tyurin, will replace the Expedition Two crew next month during the STS-105 mission.

Atlantis will undock from an International Space Station that is ready to begin independent operations. Since July 2000, 77 tons of hardware has been added to the station, including the Zvezda module, the Z1 Truss Assembly, Pressurized Mating Adapter 3, the P6 Truss and its 240-foot long solar arrays, the U.S. laboratory Destiny, the Canadarm2 and the Quest airlock.

The Atlantis crew was awakened at 4:14 p.m. Saturday by the song "Who Let The Dogs Out" sung by the Baha Men. The song was played for Hobaugh. All systems aboard both Atlantis and the International Space Station continue to function normally as the two spacecraft orbit the Earth at an average altitude of 240 statute miles.

The space walk also was the first to be supported primarily from the space station Flight Control Room in Houston, and the first demonstration of a new pre-breathing protocol that uses vigorous exercise to help purge nitrogen bubbles from the space walkers' bloodstreams and prevent what is known as "the bends."

Mission Specialists Mike Gernhardt and Jim Reilly exited the new airlock at 11:35 p.m. CDT Friday and were back inside by 3:37 a.m. Saturday. Working in tandem with the station's Canadarm2 operator and Expedition Two Flight Engineer Jim Voss and shuttle arm operator and Atlantis Commander Steve Lindsey, the space-age construction workers attached a nitrogen supply tank to the airlock's shell. This completed the installation of two nitrogen and two oxygen tanks that will be used to pressurize the airlock and resupply space suits. Atlantis Pilot Charlie Hobaugh and Station Commander Yury Usachev coordinated the space walk from inside, while Flight Engineer Susan Helms supported station arm operations.

Depressurizing the airlock took longer than expected - about 40 minutes instead of the anticipated 7 minutes. Flight controllers and engineers have not yet identified what caused the pressure equalization valve on the Crew Lock's hatch to react so slowly, but are continuing to evaluate data and reports from the crew.

During the mission's third spacewalk, Gernhardt and Reilly also moved hand-over-hand up the station's solar array truss to take a look at a gimbal assembly mechanism that allows the arrays to swivel with the Sun. They reported no visible signs that could account for high-current readings being witnessed by flight controllers on the ground.

The successful construction foray brings the total time for space station-based walks to 4 hours, 21 minutes. There have been 24 space walks devoted to station assembly, a combined total of 155 hours, 39 minutes.

The crews will go to bed at 8:04 a.m., and awaken at 4:04 p.m. to begin preparations for an undocking at 11:54 p.m. CDT Saturday. The Atlantis and Expedition Two crews will say good-bye and close the hatches at 8:59 a.m.

Pilot Charlie Hobaugh was at the shuttle's aft flight deck controls for the fly-around, which allowed the shuttle crew to take a parting look at the newly installed airlock, Quest, and the four large air supply tanks they had delivered.

Commander Steve Lindsey, Hobaugh and Mission Specialists Janet Kavandi, Mike Gernhardt and Jim Reilly, had spent 196 hours, 46 minutes - or more than 8 days - docked to the station, working with Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms to install, checkout and christen the station's newest asset.

A final separation burn at 1:14 a.m. CDT Sunday put Atlantis on its initial course for home, with landing scheduled for 11:37 p.m. CDT Monday at Kennedy Space Center.

The entire Atlantis crew took time out to discuss the mission with CNN and Fox News early Sunday, then got ready for bed about 7:30 a.m. The shuttle astronauts will awaken at 5:34 p.m. CDT Sunday and begin stowing gear and testing Atlantis' systems that will be used during re-entry and landing.

Back on the station, the Expedition Two crew will go to bed about 1 p.m. Sunday, then enjoy a day of off-duty time following the busy shuttle stay and begin shifting back to its regular schedule. So far, the Expedition Two crew has spent 136 days in space. The trio will be replaced by Expedition Three Commander Frank Culbertson and Flight Engineers Vladimir Dezhurov and Mikhail Tyurin next month during Discovery's STS-105 mission.

All systems aboard both Atlantis and the International Space Station continue to function normally as the two spacecraft orbit the Earth independently once again.

Preliminary weather forecasts show generally favorable conditions at the Shuttle Landing Facility tonight, with only a possibility of low clouds and rain within 30 miles of the runway.

The crew will begin its final deorbit preparations around 6:30 p.m. Atlantis' payload bay doors are slated to be closed at 7:49 p.m. and computers on the shuttle will be switched to landing mode at 8:01 p.m. with the crew scheduled to climb into their seats at 9:29 p.m. for the first of tonight's two landing opportunities.

The first opportunity to return to Florida begins with a deorbit burn at 10:29 p.m. resulting in an 11:37 p.m. CDT landing Monday (12:37 a.m. eastern time Tuesday.) If weather precludes a landing on the first opportunity, there is a second landing opportunity beginning with an engine firing at 12:08 a.m. and a landing at 1:14 a.m. Tuesday. For the second landing opportunity, Houston area residents would have an opportunity to watch Atlantis streak through the sky on its return to Florida. Atlantis would pass over the Houston area moving from southwest to east beginning at 12:57 a.m. Atlantis and its plasma trail should be visible in the skies for approximately two minutes as it flies at speeds between Mach 10-12 at an altitude of 130,000 feet, with less than 20 minutes to touchdown in Florida.

Aboard the International Space Station, the Expedition Two crew enjoyed a quiet day on orbit with no scheduled work, though they did spend some time working on items from their Task List. Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss went to bed at 1 p.m. and are scheduled to awaken at 9:30 p.m.

Both spacecraft continue to orbit the Earth in excellent condition at an average altitude of 240 statute miles.

Atlantis Commander Steve Lindsey, Pilot Charlie Hobaugh and Mission Specialists Janet Kavandi, Mike Gernhardt and Jim Reilly will awaken at 3:04 p.m., and begin deorbit preparations at 6:30 p.m. The shuttle's payload bay doors are slated to be closed at 7:49 p.m. Computers on the shuttle will be switched to landing mode at 8:01 p.m., and the crew will climb into its seats at 9:29 p.m.

Since the shuttle's supplies will support several more days on orbit, Entry Flight Director Wayne Hale has elected to activate landing support only at Kennedy Space Center for tonight. Forecasters are predicting generally favorable conditions at the Shuttle Landing Facility, but are watching out for the possibility of thunderstorms and rain within 30 miles.

There are two Florida landing opportunities Monday night and Tuesday morning. The first begins with a deorbit burn at 10:29 p.m. and concludes with landing at 11:37 p.m. CDT Monday. The second commences with an engine firing at 12:08 a.m. ending with landing at 1:14 a.m. CDT Tuesday.

Lindsey and Hobaugh on Sunday conducted successful tests of the reaction control system jets used to maneuver Atlantis as it begins to re-enter the Earth's atmosphere. They then checked out the flight control surfaces that become effective once the orbiter's computers sense aerodynamic drag on the vehicle.

Kavandi, Gernhardt and Reilly put away the bulk of the equipment they used during their eight days docked to the station and stowed the 2,550 pounds of equipment they are bringing home from the station.

Aboard the International Space Station, the Expedition Two crew enjoyed off-duty and exercise time. Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss did spend time talking with flight controllers in Houston and Moscow about the work ahead of them to get squared away after Atlantis' visit, and to get ready for the next shuttle mission and their replacement crew. The crew is scheduled to go to bed at 1 p.m. CDT today.

Both spacecraft continue to orbit the Earth at an average altitude of 240 statute miles.

Atlantis will try again Tuesday night. The first of two opportunities for KSC would see a landing at 10:39 p.m. CDT on the 200th orbit of the mission. The second opportunity for the Florida landing site would see Atlantis touch down on orbit 201 at 12:15 a.m. Wednesday. Weather forecasts for Florida called for improving conditions.

Conditions late Monday and early Tuesday were marginal at the Cape, but very nearly improved enough to permit landing. Showers near the landing strip prevented Atlantis' homecoming, and the decision was made to back off and try again Tuesday night without calling up landing support in California.

Atlantis Commander Steve Lindsey, Pilot Charlie Hobaugh and Mission Specialists Janet Kavandi, Mike Gernhardt and Jim Reilly reopened the shuttle's payload bay doors as they moved through procedures to back out of the landing configuration. The crew was scheduled to go to bed just after 6 a.m. Tuesday, and to be awakened a few minutes after 2 p.m. to begin landing preparations again.

On the International Space Station, the Expedition Two crew awakened about 9:30 p.m. CDT Monday for another day of light duty following the hectic pace of joint operations with the shuttle crew. Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss were informed of their colleagues' delayed return to Earth. About the only activities scheduled were continued unloading and stowage of the 2,500 pounds of supplies delivered by the Atlantis crew.

Both the shuttle and station continue to orbit at an average altitude of 240 statute miles with all systems working well.

The forecast for Kennedy Space Center calls for a few scattered clouds and no rain for both landing opportunities this evening.

Atlantis Commander Steve Lindsey, Pilot Charlie Hobaugh and Mission Specialists Janet Kavandi, Mike Gernhardt and Jim Reilly began final deorbit preparations around 5:40 p.m. for the first landing opportunity at KSC. Atlantis' payload bay doors are to be closed at 6:52 p.m. Crewmembers will climb into their seats just after 8:30 p.m. Atlantis' orbital maneuvering system engines will begin firing at 9:32 p.m. to drop the shuttle out of orbit for a 10:39 p.m. CDT landing at KSC on the 3-mile-long Shuttle Landing Facility runway.

A second landing opportunity at KSC would see a deorbit burn at 11:08 p.m. and touchdown at 12:15 a.m. Wednesday.

Aboard the International Space Station, the Expedition Two crew, Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss, will be awakened just before midnight to resume their full work schedule after two light days of activity. Flight controllers in Moscow successfully performed the fourth of five scheduled orbital adjustment burns using jet thrusters on the Progress supply vehicle docked at the rear of the Service Module Tuesday afternoon. The maneuvers are designed to optimize the station's orbit for the arrival of the next Progress vehicle in August and the Russian Docking Compartment in September.

Both spacecraft are in excellent condition, orbiting at an average altitude of about 240 statute miles.

The Atlantis crew, Commander Steve Lindsey, Pilot Charlie Hobaugh and Mission Specialists Janet Kavandi, Mike Gernhardt and Jim Reilly, spent eight days docked to the station during their almost 13-day flight. Reilly and Gernhardt completed three spacewalks to help with Quest's installation and its fitting out with four high-pressure tanks, two oxygen and two nitrogen.

Lindsey and Hobaugh fired Atlantis' orbital maneuvering system engines at 9:32 p.m. CDT to drop the shuttle out of orbit for the 10:39 p.m. landing at KSC on the 3-mile-long Shuttle Landing Facility runway. Their landing was the 55th shuttle landing and the 13th night landing at KSC. Florida weather cooperated beautifully, with none of the rain showers that caused waveoff of two landing opportunities a day earlier.

The Atlantis crew is expected to return to Houston on Thursday for a 4 p.m. public welcome home at Ellington Field's Hangar 990. For updates on crew arrival time at Ellington, please call 281 483-8600.

Aboard the International Space Station, the Expedition Two crew, Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss, will be awakened just before midnight to resume their full work schedule after two light days of activity. Flight controllers in Moscow successfully performed the fourth of five scheduled orbital adjustment burns using jet thrusters on the Progress supply vehicle docked at the rear of the Service Module Tuesday afternoon. The maneuvers are designed to optimize the station's orbit for the arrival of the next Progress vehicle in August and the Russian Docking Compartment in September.

The station is in excellent condition, orbiting at an average altitude of about 240 statute miles.

Almost immediately after Atlantis departed following its mission to install an addition on the home in space, station Commander Yury Usachev, and Flight Engineers Jim Voss and Susan Helms began unpacking and stowing supplies delivered by Atlantis, while at the same time beginning to prepare for the arrival of their replacement crew.

The Expedition Three crew consists of Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin. The three will be delivered aboard Discovery by its crew of Commander Scott Horowitz, Pilot Rick Sturckow and Mission Specialists Dan Barry and Pat Forrester.

The STS-105 and Expedition Three crews will travel to the Kennedy Space Center in Florida Sunday and the countdown begins Monday.

While Discovery's countdown to launch to the ISS is set to begin, half a world away at the Baikonur Cosmodrome in Kazakhstan, the fifth Progress supply craft is being readied for launch Aug. 21 followed Sept. 15 by the launch of the next station component - a Russian docking compartment named Pirs, the Russian word for pier.

Expedition Two Commander Yury Usachev, Voss and Helms also continue to oversee a variety of science investigations while packing for the trip home.

The International Space Station (ISS) is orbiting in excellent shape at an altitude averaging 240 miles (385 km).

The STS-105 mission to deliver the third resident crew to the ISS is scheduled to launch tomorrow at 4:38 p.m. Central time as the ISS sails over the Southern Ocean south of Adelaide, Australia at an altitude of around 240 statute miles.

Discovery's Commander, Scott Horowitz, Pilot Rick Sturckow, and Mission Specialists Pat Forrester and Dan Barry are ready to ferry Expedition Three Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin to the Station for a four-month mission, succeeding Usachev, Voss and Helms, who have been aloft since March 8.

Discovery was cleared for launch earlier this week by Shuttle managers after reviewing the status of fuel injector units used in the hydraulic power units that steer the Shuttle's solid rocket booster nozzles during the first two minutes of powered flight.

Last night aboard the ISS, one of three command and control computers (C & C 1) which is used as a backup for the operation of some Station systems experienced a problem reading its hard drive, or Mass Storage Device. The hard drive stores commands for a variety of vehicle activities on the U.S. segment of the complex. Flight controllers attempted to reboot the computer with no success and are continuing efforts to bring it back into operation. This computer has lost only some of its functional capability. The Station's primary computer (C & C 3) is operating normally, however, and a third computer (C & C 2) is being transitioned from standby status to act as the backup for C & C 3.

A newly refurbished command and control computer had already been manifested to be launched on Discovery to the ISS as a spare, and would be installed for operation, if required. The backup computer glitch has had no impact on Station operations and will not affect the joint mission to deliver the new Expedition crew to the orbital outpost.

As Usachev, Voss and Helms prepared to handover command of the Station to a new crew, Russian engineers prepared two vehicles for launch right after the STS-105 mission. At the Baikonur Cosmodrome in Kazakhstan, a Progress resupply ship is being readied for launch on August 21 to deliver food, fuel and supplies for the new Expedition Three crew. It is scheduled to dock to the aft docking port of the Zvezda Service Module on August 23, one day after the current Progress attached to the ISS is jettisoned. And the newest ISS module, a Russian Docking Compartment named Pirs, the Russian word for pier, is in the final stages of preparation for launch on September 15 to link up to the earthward facing docking port of Zvezda. It will provide a new docking port for future visiting Russian vehicles.

In addition to packing to come home, the Expedition Two crew continues to oversee a variety of science investigations.

The International Space Station (ISS) is orbiting at an altitude averaging 240 miles (385 km).

As the station sailed over the Pacific Ocean southwest of the border between Mexico and Guatemala, Discovery rocketed away from Launch Pad 39-A at the Kennedy Space Center at 4:10 p.m. Central time en route to a rendezvous and docking Sunday afternoon.

Aboard Discovery were Commander Scott Horowitz, Pilot Rick Sturckow and Mission Specialists Pat Forrester and Dan Barry along with Expedition Three Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin. They will replace the Expedition Two crew, Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms, who were wrapping up their 155th day in space at the time of Discovery's launch.

Less than nine minutes after beginning its journey, Discovery settled into its preliminary orbit as the crew prepared to open the ship's payload bay doors prior to receiving the green light to begin orbital operations. This is the fifth shuttle mission of the year.

Discovery's crew will spend the next few hours unpacking equipment, setting up computers and conducting the first in a series of engine firings to refine the shuttle's orbit as it heads for the station. The crew will begin an eight-hour sleep period shortly after 11 p.m. and will be awakened at 7:15 a.m. Saturday for its first full day in orbit. That day will be devoted to preparations for Sunday's rendezvous and docking and eight days of joint operations with the Expedition Two crew, highlighted by the official transfer of command of the station from Usachev to Culbertson.

Aboard the station, Usachev, Voss and Helms have spent most of the past couple of weeks packing gear for the trip home aboard Discovery, and tidying up for the arrival of visitors about 1:30 p.m. Sunday.

Discovery is in an orbit inclined 51.6 degrees to either side of the Equator with all of its systems operating normally.

Discovery's astronauts and cosmonauts, Commander Scott Horowitz, Pilot Rick Sturckow and Mission Specialists Pat Forrester and Dan Barry, and Expedition Three Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin, were awakened to "Back in the Saddle Again" by Gene Autry. It was played for Culbertson, making his third flight into space, eight years after he last flew.

At the time the crew was awakened, some 8000 statute miles separated Discovery from the ISS. A second firing of Discovery's orbital maneuvering systems engines is scheduled for early in the crew's day today to further adjust its orbit in preparation for rendezvous and docking with the station. Also scheduled today are the checkout of spacesuits to be worn by Barry and Forrester during two spacewalks next week, the preparation of rendezvous and navigation tools and a test of the shuttle's robotic arm, all routine work on the day before docking. Crewmembers also will perform a camera survey of Discovery's cargo bay with arm-mounted cameras.

Discovery is scheduled to linkup to the ISS tomorrow at 1:37 p.m. Central time as the two spacecraft fly over the Indian Ocean northwest of Australia, just south of the Indonesian island of Jawa.

The major objective of the STS-105 mission of Discovery is the swapout of the new resident Station crew, led by Culbertson, with the Expedition Two crew, Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms, who have been aboard the Station more than five months. They are to return to Earth aboard Discovery on August 22.

Discovery also is bringing equipment, supplies and scientific experiments to the Station. Almost 7,000 pounds of that cargo is in Leonardo, the Italian-built Multipurpose Logistics Module in Discovery's cargo bay. Once that is transferred to the station, Leonardo will be packed with other equipment, unused items and trash for return to Earth.

During their eight days docked to the station, Discovery Mission Specialists Barry and Forrester will perform two spacewalks. On the first, next Thursday, they will install a device called an Early Ammonia Servicer on the Station. It contains spare ammonia that could be used to cool Station systems should it be needed. During the second spacewalk, two days later, they will install heater cables for the station's large S0 truss segment, which will be delivered on a future mission, as well as handrails.

Discovery is orbiting the Earth in excellent shape with no issues being worked by the flight control team.

Commander Scott Horowitz, Pilot Rick Sturckow and Mission Specialists Pat Forrester and Dan Barry, along with Expedition Three Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin, checked out Shuttle systems, navigational tools and docking hardware in advance of Discovery's planned linkup to the ISS.

The docking is scheduled to occur Sunday at 1:38 p.m. Central time over the Indian Ocean northwest of Australia, just south of the Indonesian island of Jawa.

Forrester and Horowitz powered up, unfurled and checked out Discovery's 50-foot long robotic arm, which will be used by Forrester to move the Leonardo cargo module from Discovery's payload bay to the ISS for the transfer of food and supplies, and by Horowitz to transport Barry and Forrester around the Station during their two spacewalks next week.

In addition, Barry and Forrester tested the devices they will use tomorrow to measure Discovery's distance from the ISS and its rate of closure on the complex during the terminal phase of the Shuttle's approach to the Station. Discovery's docking mechanism was also checked out and its outer docking ring extended to ensure it is ready for tomorrow's capture of the ISS docking port on the forward end of the Station's Destiny laboratory module.

Next week, Barry and Forrester will test the spacesuits they will wear during their two excursions outside Discovery to attach a spare cooling reservoir to the ISS and to hook up heating cables for a large truss structure that will be mounted to the Station next year.

The crew enjoyed a few hours of spare time this afternoon to relax as they wound down for the start of an eight-hour sleep period just after 9 p.m. Central time tonight.

Aboard the ISS, Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms spent the day packing up personal items and preparing Station systems for tomorrow's arrival of their replacements, Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin. This was the 156th day in space for the current occupants of the ISS.

The exchange of crew members on the Station will occur on Monday, although formal command of the Station will not be transferred from Usachev to Culbertson until a few hours before Discovery's undocking on August 20.

Almost 7,000 pounds of food, supplies and personal items for the Expedition Three crew are housed in Leonardo, the Italian-built Multi-Purpose Logistics Module (MPLM).

Once the module is transferred to the Station and unpacked, it will be filled with equipment no longer needed on the ISS, including Expedition Two crew clothing and trash for return to Earth.

Discovery is orbiting the Earth in excellent shape with no issues being worked by the flight control team.

Discovery Commander Scott Horowitz, Pilot Rick Sturckow and Mission Specialists Pat Forrester and Dan Barry, along with the Expedition Three crew, will begin rendezvous operations a little before 9 a.m. today. The shuttle will begin a final approach to the station from a point about 9 miles behind the outpost with the last major rendezvous maneuver scheduled at around 11:15 a.m.

With Discovery about 600 feet directly below the station, Horowitz will fly the shuttle in a quarter circle to a point in front of the complex. From there he will very slowly and precisely maneuver Discovery toward the station, pausing about 30 feet from the ISS to precisely align the docking mechanisms of the two craft.

Docking is expected to occur at 1:38 p.m. over the Indian Ocean just south of the Indonesian island of Jawa. The hatches separating the two spacecraft are to be opened around 3:30 p.m. allowing the current station residents, Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms to greet their replacements and the Discovery astronauts who will bring them home after more than five months in space.

ISS flight controllers are expected to ask the Expedition Two crew on Wednesday to try to reboot one of three command and control computers which experienced a hard drive problem last week and which has been put in standby mode with no impact to station operations. If the reboot does not recover the use of the hard drive, the crew may be asked to replace a component in the computer with a spare being brought to the station on Discovery. Two other command and control computers, a prime and a backup, are working perfectly in support of U.S. segment systems.

Discovery is orbiting the Earth every 90 minutes in good shape in pursuit of the International Space Station.

Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms looked on from the station's Destiny laboratory as Discovery arrived this afternoon, then worked in concert with their Shuttle counterparts to ensure a tight seal and a firm mate between the two vehicles.

At 3:41 p.m., hatches finally swung open between Discovery and the ISS, and the two crews greeted one another. First aboard the station was Culbertson to survey his home for the next four months. Within minutes, all ten astronauts and cosmonauts had shared greetings before settling in for a station safety briefing conducted by Usachev.

Monday the crews will attach the Leonardo cargo carrier to the station at about 9:30 a.m. and begin unloading its supplies.

Just prior to this operation, the two station crews will systematically begin the process of handing over command from Expedition Two to Expedition Three. The plan is for Culbertson and Helms to remove her form-fitting seat liner from the Soyuz spacecraft and replace it with Culbertson's at about 7 a.m. Two hours later at about 9 a.m., Dezhurov and Usachev will do the same followed at 12:30 p.m. by the seat liner swap of Tyurin and Voss. The Soyuz is used as a return vehicle in the event of a problem on the station.

Crew sleep is scheduled for about 8 tonight with a musical wakeup call from Mission Control at 5:10 a.m. Monday.

The station and shuttle complex is orbiting the Earth every 92 minutes in good shape.

Once they swap out their custom-made Soyuz capsule seat liners with those belonging to Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms, Culbertson, Dezhurov and Tyurin will become the third trio of residents to inhabit the complex, while Usachev, Voss and Helms become members of Discovery's crew.

The Soyuz serves as a crew return vehicle in the unlikely event it should become necessary to leave the station.

Official handover of command of the ISS from Usachev to Culbertson will take place on August 20, shortly before Discovery undocks from the Station.

After the crew transfer is complete, the oncoming ISS residents will begin a comprehensive handover with their departing counterparts, receiving briefings on Station systems, the current configuration of hardware and computers and procedures they will employ during their first days on board the outpost.

Mission Specialist Pat Forrester will use Discovery's robot arm to move the Italian-built Leonardo cargo module from the shuttle's payload bay to the nadir docking port of the Station's Unity module so it can be unloaded of more than three tons of supplies and equipment for the newly arrived Expedition Three crew. Leonardo also contains racks of scientific experiments which will greatly enhance the scientific research on board the ISS over the next few months. Leonardo will be installed on the Station late this morning.

Other equipment will be transferred throughout the day from Discovery's middeck lockers to the ISS as the crews work in concert to set the stage for the Expedition Three mission.

The joined spacecraft are orbiting at an average altitude of about 244 statute miles, completing an orbit of the Earth every 90 minutes. Both craft are in good condition.

That marked the end of the Expedition Two crew's stay on the station at 148 days since it took over for the first resident crew on March 18. By the time the Expedition Two crew lands aboard Discovery next week, Yury Usachev, Jim Voss and Susan Helms will have spent 163 days aboard the station and 167 days in space.

The official ceremonial handover of command of the ISS from Usachev to Culbertson will take place Aug. 20, shortly before Discovery undocks from the Station.

The systematic swap of the seat liners and space suits occurred in and around the installation of the Leonardo Multipurpose Pressurized Logistics Module onto the station. Leonardo is one of three cargo supply vessels designed to deliver food, clothing, experiments and other hardware to and from the station throughout its orbital life. It was attached to the station at 10:55 a.m. CDT and its hatch opened at 2:47 p.m. CDT.

Now that the official crew transfer is complete, the Expedition Three crew of Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin will begin a comprehensive handover with their departing counterparts, receiving briefings on station systems, the current configuration of hardware and computers and procedures they will employ during their first days on board the outpost.

The crew will be awakened at 4:10 a.m. CDT Tuesday to continue the unloading of more than three tons of supplies and experiments from Leonardo. At 2 p.m. CDT Tuesday, the two station commanders, Culbertson and Usachev, will take part in an interview from space with television networks. The interview will air live on NASA TV.

The joined spacecraft are orbiting at an average altitude of about 244 statute miles, completing an orbit of the Earth every 90 minutes.

Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms will continue handover briefings with the Expedition Three crew. The new station commander, Frank Culbertson, and Russian cosmonauts Mikhail Tyurin and Vladimir Dezhurov have taken up residence aboard the station. The Expedition Two crewmembers, who spent more than five months on the station, will return home aboard Discovery next week.

Aboard Discovery, Commander Scott Horowitz, Pilot Rick Sturckow, and Mission Specialists Pat Forrester and Dan Barry, along with the Expedition Two crewmembers, were awakened at 4:10 a.m. Central time to the sounds of "Time Bomb", a song performed for Forrester by his sons, Patrick and Andrew.

On the heels of their successful space walk yesterday to install an ammonia coolant reservoir and a suite of experiments on the station, Barry and Forrester will be reviewing procedures and will check out hardware for the mission's second space walk on Saturday to hook up heater cables for a truss structure to be delivered to the station next year

Horowitz and Sturckow will perform the mission's second reboost of the station this morning, this one to raise the ISS' altitude by about two statute miles. The three Russian crewmembers aboard the shuttle/station complex will field questions from Russian reporters at the Russian Mission Control Center outside Moscow at 11:15 a.m. Central time. Three hours later, at 2:15 p.m., all ten crewmembers will hold a news conference with U.S. reporters at NASA centers. At 3 p.m., the crewmembers will gather for a change of command ceremony on the station as Expedition Two Commander Usachev passes the baton to Expedition Three Commander Culbertson. The formal handover of command actually occurred late Monday afternoon after the crews exchanged custom-made Soyuz seat liners for the return capsule docked to the station.

Discovery and the station are orbiting the Earth every 90 minutes at an average altitude of 244 statute miles with systems functioning well.

Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms continued handover briefings with the Expedition Three crew while stowage of equipment, discarded items and belongings of the Expedition Two crew continued aboard the Leonardo Multi-Purpose Logistics Module for return to Earth.

The new station Commander, Frank Culbertson, and Russian cosmonauts Vladimir Dezhurov and Mikhail Tyurin, officially took command of the station Monday afternoon to begin a four month stay on the ISS. The Expedition Two crewmembers, which spent more than five months on the station, will return home aboard Discovery next week.

In preparation for the space walk set to begin about 9 a.m. Saturday, Dan Barry and Pat Forrester reviewed procedures and checked hardware that will be used during the excursion outside the station to hook up heater cables for a truss structure to be delivered to the station next year.

Shuttle Commander Scott Horowitz and Pilot Rick Sturckow performed the mission's second reboost of the station early in the day, raising the average altitude of the ISS by 2.2 statute miles (3.5 kilometers). Discovery's thrusters were systematically fired 253 times over the course of an hour. It was the final reboost planned prior to Discovery's departure Monday morning.

The crew heads to bed about 9 tonight, Central time and will be awakened by Mission Control at 4:10 a.m. CDT Saturday.

Discovery and the station are orbiting the Earth every 90 minutes at an average altitude of 247 statute miles with all systems functioning well.

Discovery's crew, including the returning Expedition Two crewmembers, were awakened shortly after 4 a.m. Central time by the sounds of "Under the Boardwalk" by the Drifters, played for Jim Voss by his wife Suzan.

Leonardo brought almost 7,000 pounds of material to the station, including equipment, supplies and two scientific racks for the new Expedition Three crew of Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin. Leonardo, which is one of three pressurized cargo carriers for station resupply activities provided by the Italian Space Agency, is completing its second visit to the station.

Mission Specialist Pat Forrester will use the shuttle's robotic arm this afternoon to unberth Leonardo from the station and move it to Discovery, beginning the one-hour operation a little before 12:30 p.m. He will be backed up by Discovery Commander Scott Horowitz, who operated the arm during two successful space walks by Forrester and Dan Barry to outfit the station with critical spare equipment and scientific gear.

Overnight, controllers reworked the crewmembers' flight plan to give them some time off this afternoon after Leonardo is returned to Discovery. The day will be highlighted by final handover discussions between the two Expedition crews before hatches are closed one last time between Discovery and the station tomorrow morning just before 7 a.m. Central time. Discovery is scheduled to undock from the ISS at 9:52 a.m. Central time Monday to set the stage for a landing at the Kennedy Space Center Wednesday afternoon, completing 167 days in space for Expedition Two Commander Yury Usachev, Voss and Susan Helms.

Meanwhile, Russian space officials are all set to launch a new Progress resupply craft to the International Space Station on Tuesday at 4:24 a.m. Central time for a docking early Thursday. The Progress will carry supplies, food and equipment for the new Expedition Three crew. The Progress currently docked to the aft end of the Zvezda Service Module will be undocked on Wednesday and commanded to a destructive reentry in Earth's atmosphere.

Discovery and the ISS are orbiting the Earth every 90 minutes at an altitude of 246 statute miles with all systems functioning normally.

The ten crewmembers aboard Discovery and the station are spending their final day and night together prior to the farewell ceremony and hatch closing scheduled for about 7 a.m. CDT tomorrow. That follows the wakeup call from Mission Control set for 4:40 a.m.

Leonardo brought almost 7,000 pounds of material to the station, including equipment, supplies and two scientific racks for the new Expedition Three crew of Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin. Leonardo - one of three pressurized cargo carriers provided by the Italian Space Agency - completes its second visit to the station.

Astronaut Pat Forrester carefully removed the high-tech moving van from the station and placed it back in Discovery's payload bay at 2:15 p.m. CDT. He was backed up throughout the operation by Discovery Commander Scott Horowitz, who operated the arm during the spacewalks by Forrester and Dan Barry to outfit the station with spare equipment and scientific gear.

Once Discovery departs, Pilot Rick Sturckow will perform a strategic fly around of the station at a distance of about 400 feet before firing thrusters shortly after 11 a.m. to depart the vicinity of the complex. Wednesday afternoon, Discovery is set to return to the Kennedy Space Center with the Expedition Two crew of Yury Usachev, Jim Voss and Susan Helms. The three departed the Florida spaceport March 8 and will return after 167 days in space.

Meanwhile, Russian space officials are set to launch the fifth Progress resupply craft to the International Space Station Tuesday at 4:24 a.m. Central time followed by an automatic docking early Thursday. The Progress will carry supplies, food and equipment for the new Expedition Three crew. Its predecessor will be undocked Wednesday and commanded to burn up harmlessly in Earth's atmosphere.

Discovery and the ISS are orbiting the Earth every 90 minutes at an altitude of 246 statute miles with all systems functioning normally.

The final farewells and hatch closing are scheduled for just before 7 a.m. Central time. Discovery's crewmembers, Commander Scott Horowitz, Pilot Rick Sturckow, and Mission Specialists Pat Forrester and Dan Barry, assisted by the returning Expedition Two crew, Commander Yury Usachev and Astronauts Jim Voss and Susan Helms, will undock Discovery at 9:52 a.m. as the two craft sail over the south Pacific due west of the southern coast of Chile.

With Sturckow at the controls, the shuttle will conduct a flyaround of the station, circling it 11/4 times before the shuttle's jets are fired at 11:12 a.m. to drop Discovery into a lower orbit for final separation from the station.

The seven crewmembers aboard Discovery were awakened at 3:40 a.m. by the sounds of "Brand New Day," played by Sting. The song was for Helms, requested by her family and friends. She and her Expedition Two crewmates are wrapping up five and a half months on orbit.

Parked in Discovery's cargo bay is Leonardo, the Multi-Purpose Logistics Module that brought 7,300 pounds of material to the station, including equipment, supplies and two scientific racks. It is returning to Earth with almost 2 tons of unneeded equipment from the station, trash and personal effects of the Expedition Two crew.

Expedition Three Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin are beginning a science-intensive increment that is scheduled to end with their replacement by the Expedition Four crew late this year.

Also on today's schedule for Discovery's crewmembers after undocking is the deployment of a small science satellite called Simplesat, designed to evaluate the use of inexpensive commercially available hardware in space. It is designed to demonstrate GPS attitude control and pointing in free flight. It will be spring-ejected from a canister at the rear of the Shuttle's cargo bay.

The Russians are all set to launch an unmanned Progress resupply craft from the Baikonur Cosmodrome in Kazakhstan tomorrow at 4:24 a.m. Central time. It is the fifth Progress to be launched to the station, and is scheduled to dock a little after 5 a.m. on Thursday, the day after the current Progress attached to the ISS is undocked from the rear of the Zvezda Service Module to burn up in the atmosphere with its load of trash.

Discovery and the ISS are circling the Earth every 90 minutes at an altitude of 246 statute miles. All systems are functioning well.

The final farewells and hatch closing occurred at 7 a.m. Central Monday just prior to closing the hatches and conducting leak checks between the two vehicles. Under control of Pilot Rick Sturckow, Discovery gently backed away from the station to a distance of about 450 feet. At that point, Sturckow performed a fly-around of the complex allowing for photo documentation and a final look by Yury Usachev, Jim Voss and Susan Helms at their home for the past five and a half months.

Returning with Discovery is the Leonardo Multi-Purpose Logistics Module that brought equipment, supplies and two scientific racks to the station. It is returning to Earth with more than a ton of equipment, experiments, personal effects and unneeded hardware.

Also today, Discovery's crewmembers deployed a small science satellite called Simplesat, designed to evaluate the use of inexpensive commercially available hardware in space. It is designed to demonstrate Global Positioning System attitude control and pointing in free flight. It was spring-ejected from a canister at the rear of the Shuttle's cargo bay.

Tuesday is a day devoted to packing up the orbiter and checking its landing systems for the planned return to the Kennedy Space Center Wednesday. Landing is set for just before Noon Central time with weather conditions expected to be favorable with light winds and only a slight chance of rain predicted in the area.

Meanwhile, on the steppe of the Kazak desert, a Soyuz rocket is poised to launch an unmanned Progress supply ship to the station tomorrow at 4:24 a.m. Central time. It is the fifth Progress to be launched to the station, and is scheduled to dock a little after 5 a.m. Thursday, the day after the current Progress attached to the ISS is undocked from the rear of the Zvezda module to burn up in the atmosphere.

The two spacecraft are at slightly different orbits, circling the Earth every 90 minutes. All systems are in excellent shape.

Leading the station now by more than a thousand miles, Discovery's aero surfaces and maneuvering engines were tested early today by the shuttle's Commander Scott Horowitz and Pilot Rick Sturckow while the remaining crewmembers busily prepared the cabin for the high-speed reentry.

Late in the day, the reclining seats that will be occupied by Expedition Two Commander Yury Usachev, and Flight Engineers Jim Voss and Susan Helms were put into position on the orbiter's middeck. The reclined position has been proven to be the most comfortable method of return to Earth from space by long duration crewmembers.

Weather forecasters are predicting favorable conditions in Central Florida for Discovery's return to Earth, prompting mission managers to forego calling up support at the backup landing site in California.

To prepare for deorbit and landing activities, the shuttle crew will awaken at 3:10 a.m. Wednesday and start deorbit preparations about 6:45 a.m. The payload bay doors are to be closed at about 8 a.m. with the deorbit firing of the twin Orbital Maneuvering System engines on the tail of Discovery targeted for 10:37 a.m.

While Discovery was readied for the trip home, the Expedition Three crew of Frank Culbertson, Vladimir Dezhurov and Mikhail Tyurin activated one of the two scientific racks delivered by Discovery's crew. The crew also prepared for the undocking of a Progress supply vehicle docked to the station since late May. The undocking is set for 1:05 a.m. Wednesday to make room for the next Progress already on its way following launch at 4:24 a.m. today from the Baikonur Cosmodrome in Kazakhstan. As was its four predecessors, the 5 Progress is loaded with fuel, food and other equipment for use by the Expedition Three crew.

The launch pad now is free for the next launch of a Soyuz Sept. 15 delivering the Russian Docking Compartment to the station.

Discovery is circling the Earth every 90 minutes at an average altitude of about 240 statute miles. Systems aboard it and the International Space Station are in excellent shape.

Discovery Commander Scott Horowitz, Pilot Rick Sturckow, and Mission Specialists Pat Forrester and Dan Barry, along with Expedition Two crewmembers Commander Yury Usachev, and Astronauts Jim Voss and Susan Helms, were awakened at 3:10 a.m. CDT to the sounds of "East Bound and Down" by Jerry Reed, at the request of their Houston-based training team.

Activities on board Discovery will focus on tomorrow's planned return trip to Earth as the astronauts stow away the equipment and hardware used during their mission and verify the performance of Discovery's landing systems. Horowitz, Sturckow and Barry will conduct the standard day-before-landing checkouts of the flight control surfaces, the rudder and flaps that will control the shuttle during its descent through the atmosphere.

Later in the day, they will set up three recumbent seats on Discovery's middeck for use by the returning Expedition Two crewmembers during Wednesday's re-entry. The seats are designed to minimize the forces of reentry after their more than five months in space.

Expedition Three crewmembers Frank Culbertson, Vladimir Dezhurov and Mikhail Tyurin, were awakened about 12:30 a.m. to begin their first day alone aboard the space station. The day's plan includes activation and checkout of Express Rack 4 - one of two scientific racks for the U.S. laboratory Destiny delivered during STS-105 - exercise and a review of plans for unloading the next Russian unpiloted cargo carrier, Progress 5, scheduled to arrive at the station Thursday morning.

Crewmembers also activated the current Progress vehicle, docked at the rear of the station's Zvezda module, before closing the hatches that connect it to the station. Progress 4 is scheduled to be undocked from the station shortly after 1 a.m. Wednesday. The new Progress supply ship - Progress 5 - was launched on a Soyuz rocket at 4:24 a.m. today from the Baikonur Cosmodrome in Kazakhstan and is scheduled to dock at the station about 5 a.m. Thursday with its cargo of fuel, food and equipment.

Discovery is circling the Earth every 90 minutes at an average altitude of about 240 statute miles. Systems aboard the shuttle and the International Space Station are functioning well.

Discovery is about 1,300 statute miles ahead of the space station and widening the gap by about 50 miles per 90-minute orbit. The seven-member crew - Commander Scott Horowitz, Pilot Rick Sturckow, Mission Specialists Dan Barry and Pat Forrester, along with the returning Expedition Two crew members, Commander Yury Usachev and Flight Engineers Susan Helms and Jim Voss - were awakened at 3:10 a.m. CDT to begin a day with two landing opportunities at Florida's Kennedy Space Center. Weather conditions in Florida hold promise for today's landing, but the entry team of flight controllers will be watching for a chance of rain near the landing site.

The first opportunity would see a deorbit burn at 10:37 a.m., resulting in an 11:46 a.m. CDT (12:46 p.m. EDT) landing. Discovery would descend across southern Mexico, cross the Bay of Campeche, skirt the northwestern tip of the Yucatan Peninsula, and cross the Gulf of Mexico before making landfall on Florida's western coast. For the second opportunity, the deorbit burn would occur at 12:17 p.m. The shuttle would cross northern Mexico, descend over the Rio Grande near Laredo, and fly along the Gulf Coast before crossing the Florida peninsula for a 1:23 p.m. landing.

Aboard the International Space Station, the Expedition Three crew - Commander Frank Culbertson and Cosmonauts Vladimir Dezhurov and Mikhail Tyurin - were awakened a little after midnight for the undocking of the Progress 4 vehicle. That spacecraft was moved to make way for the Progress 5 cargo vehicle which launched at 4:24 a.m. Tuesday from the Baikonur Cosmodrome in Kazakhstan and is scheduled to dock at the rear of the space station's Zvezda Service Module about 5 a.m. tomorrow.

Progress 4 docked to the space station last May 22 with a cargo of equipment, food, fuel and spare computer parts. After unloading, it was refilled with trash. Just before 1 a.m. flight controllers at Moscow's Mission Control Center sent the command for it to undock. About three minutes later, springs pushed it away from the station, and three minutes after that, Progress jet thrusters were fired to increase the separation rate. At about 4 a.m. a deorbit burn command initiated its descent to fiery destruction in the Earth's atmosphere.

Discovery is circling the Earth every 90 minutes at an average altitude of about 240 statute miles. Systems aboard the shuttle and the space station are functioning well.

Following a one-orbit wave-off due to a rain shower that popped up off the end of the landing strip, STS-105 Commander Scott Horowitz fired Discovery's engines to begin the shuttle's return through the atmosphere, concluding a 4.3 million mile voyage. On Discovery's middeck, the Expedition Two crew - Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms - rode home in recumbent seats designed to lessen the effects of gravity.

Following routine medical examinations, the STS-105 crew - Horowitz, Pilot Rick Sturckow and Mission Specialists Dan Barry and Pat Forrester - along with the Expedition Two crew, will be reunited with their families. All seven crewmembers are expected back in Houston about 5 p.m. Thursday for a public welcome home ceremony at Ellington Field.

During their 12 days on orbit, the STS-105 astronauts worked with both the returning Expedition Two crew and newly-arrived Expedition Three crew to transfer more than two tons of experiment hardware, food and logistical supplies between Discovery and the station. In addition, Barry and Forrester performed two spacewalks to prepare the station for future growth.

In the meantime, aboard the International Space Station, the Expedition Three crew - Commander Frank Culbertson and Cosmonauts Vladimir Dezhurov and Mikhail Tyurin - are preparing for the arrival of a Progress 5 cargo vehicle which is scheduled to dock to the aft docking port of the Zvezda module of the Station about 5 a.m. tomorrow.

The unmanned Progress 5 craft linked up to the aft docking port of the Zvezda Service Module at 4:51 a.m. Central time (951 GMT) after an automated two-day excursion following its launch Tuesday from the Baikonur Cosmodrome in Kazakhstan. The docking occurred over Central Asia.

Within a few minutes after docking, hooks and latches were commanded to close between the Progress and Zvezda, forming a hard mate and a tight seal between the two craft. Hatches between the two vehicles will be opened later today, enabling Station Commander Frank Culbertson, Pilot Vladimir Dezhurov and Flight Engineer Mikhail Tyurin to unload some 3000 pounds of supplies and personal effects.

The arrival of the Progress vehicle at the Station sets the stage for the launch of the next module for the outpost next month --- the Russian Docking Compartment named Pirs, the Russian word for pier. The Docking Compartment will automatically link up to the nadir, or earthward facing docking port of Zvezda two days after launch, providing an additional docking port for future Russian vehicles arriving at the ISS.

At the Kennedy Space Center, Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms are in excellent shape, readapting to gravity and enjoying life back on Earth after167 days in space, 163 days of which were spent aboard the ISS. They are scheduled to return to Ellington Field in Houston late this afternoon with their Discovery crewmates, Commander Scott Horowitz, Pilot Rick Sturckow and Mission Specialists Pat Forrester and Dan Barry following yesterday's landing of Discovery at the Florida spaceport.

In addition to attending to the newly arrived Progress craft, the Expedition Three crew continues to oversee a variety of science investigations.

The International Space Station (ISS) is orbiting at an altitude averaging 240 miles (385 km).