Weber Credit - www.spacefacts.de

Personal: Female, Married. Born in Cleveland, Ohio, USA. PhD

Astronaut Career

Astronaut Group: NASA Group 14 - 1992. Inactive Entered space service: 31 March 1992. Left space service: December 2002. Number of Flights: 2.00. Total Time: 18.77 days.

NAME: Mary Ellen Weber, Ph.D.

NASA Astronaut

PERSONAL DATA:

Born August 24, 1962 in Cleveland, Ohio, and Bedford Heights, Ohio is her hometown. She is married to Jerome L. Elkind, whose hometown is Bayonne, New Jersey. She is an avid skydiver, and also enjoys scuba diving and flying. Her mother, Joan Weber, currently resides in Mentor, Ohio; her father, Andrew Weber, Jr., is deceased.

EDUCATION:

Graduated from Bedford High School in 1980; received a Bachelor of Science degree in chemical engineering from Purdue University in 1984, and a Ph.D. in physical chemistry from the University of California at Berkeley in 1988.

EXPERIENCE:

During her undergraduate studies at Purdue, Dr. Weber was an engineering intern at Ohio Edison, Delco Electronics, and 3M. In her doctoral research at Berkeley, she explored single-collision ion-molecule reactions involving silicon. She then joined Texas Instruments to research new techniques in microelectronics manufacturing, applying models of film growth to improve reactor designs. She was assigned by Texas Instruments to SEMATECH, a U.S. semiconductor manufacturing consortium, and subsequently to Applied Materials and Technology, to develop a world-class high-density plasma reactor, which went into production in 1993. To date, she has received one patent and published eight technical papers.

Dr. Weber has logged over 2,500 skydives since 1983. She received a silver medal in the U.S. National Skydiving Championships, 20-way freefall formation event, in both 1995 and 1991, and was in the world's largest freefall formation, a 297-way, in 1996. She is also an instrument-rated pilot.

NASA EXPERIENCE:

Dr. Weber was selected by NASA in the fourteenth group of astronauts, and reported to the Johnson Space Center in 1992. In her technical assignments within the Astronaut Office, she has assisted in the processing and launch of Shuttles at the Kennedy Space Center, and in payload and robotics development. In administrative assignments, she was chairman of the Source Evaluation Board for procurement of a biotechnology contract, and member of the Station Research Facilities Assessment Review Team. She is currently assigned to Legislative Affairs at NASA Headquarters, as a liaison to Congress.

Dr. Weber flew aboard the Space Shuttle Discovery on STS-70, which launched from the Kennedy Space Center on July 13, 1995, and returned there July 22, 1995. The five-member crew deployed the sixth NASA Tracking and Data Relay Satellite, and performed a myriad of scientific experiments. Dr. Weber's primary roles were in check out and deploy of the satellite, operation of biotechnology experiments, and as contingency spacewalk crew member, flight crew, and medical officer. During this nine-day mission, Discovery completed 142 orbits of the Earth and traveled 3.7 million miles.

• 13 July 1995 Flight: STS-70. Flight Up: STS-70. Flight Back: STS-70. Flight Time: 8.93 days.

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

5 December 1992 - NASA Astronaut Training Group 14 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.. Four pilots and 15 mission specialists, nine civilians and ten military. Chosen from 2054 applicants, 87 of which screened in December 1991/January 1992. Five additional international astronauts.

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

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.

Atlantis' Commander Jim Halsell and Pilot Scott Horowitz tested the navigation equipment and flight controls they will use late tonight to rendezvous with and then dock to the station. They also fired Atlantis' engines periodically to adjust the rate at which the Shuttle is closing in on the station. Atlantis is 430 statute miles behind the station now, closing in 30 statute miles with each orbit of Earth. Atlantis will continue that closing rate throughout the day while the crew sleeps.

During an engine firing Friday evening using both large orbital maneuvering system (OMS) engines on Atlantis, flight controllers saw an indication that one of two propellant valves for the left OMS engine may have failed to close. The engine's backup valve did operate normally, and the engine remains in good operating condition. However, as a precaution, the left engine will not be used again until Atlantis is ready to deorbit at the completion of the flight. Controllers are continuing to analyze the information and are uncertain if the valve actually did not operate properly or whether the indication may have been an errant sensor reading. The right OMS engine alone can be used for large rendezvous engine firings with no impact on the mission.

Astronauts Jeff Williams and Jim Voss checked the spacesuits and equipment they will use during the upcoming spacewalk, finding them in good shape. Three suits -- one for Williams, one for Voss and a spare, which could be used by either -- were checked out aboard Atlantis. Williams and Voss were assisted in the checks by Horowitz, who will coordinate the spacewalk activities from within the cabin. Later, fellow crew member Mary Ellen Weber successfully tested the Shuttle's robotic arm. Weber will operate the arm during the spacewalk to maneuver Williams and Voss between Atlantis and the station. Weber uncradled the arm this morning and used it to survey the Shuttle's payload bay. Later, Weber powered on the docking system Atlantis will use to attach to the station and extended the system's docking ring. The ring latches onto the station when the Shuttle makes contact and is then retracted to secure the two spacecraft together.

The crew will begin a sleep period at 8:11 a.m. and awaken at 4:11 p.m.. At 8:39 p.m., with Atlantis trailing the International Space Station by about 50,000 feet, Halsell will fire the Shuttle's engines to initiate the final phase of the rendezvous. Just before 10 p.m., as Atlantis reaches a point about a half-mile below the station, Halsell will take over manual control of the approach. He will reach a distance of about 170 feet from the station at 10:39 p.m. Docking is expected at about 11:31 p.m. Atlantis is in an orbit with a high point of 204 miles and a low point of 199 miles, circling Earth every 90 minutes.

Halsell and his crew performed the rendezvous and docking with the station by the book, docking on target at 11:31 p.m. CDT Saturday. Although Atlantis is now firmly attached to the station, the astronauts will not enter the new outpost until Monday, turning their immediate attention instead to a six and half-hour spacewalk to begin late tonight.

Astronauts Jim Voss and Jeff Williams will perform tonight's spacewalk to install the final part of a Russian-built crane on the station's exterior; replace a faulty communications antenna; and install various cables and handrails. Following the docking, Voss and Williams spent several hours this morning preparing the tools and equipment they will use for the sojourn outside and double-checking the spacewalk plans with the rest of the crew.

The crew also lowered the air pressure inside Atlantis from the standard sea-level pressure of 14.7 pounds per square inch to 10.2 pounds per square inch, a pressure equivalent to that felt at an altitude of 10,000 feet on Earth. The lower cabin pressure helps Voss and Williams purge nitrogen from their bodies to avoid decompression sickness when they go to the 4.2 pounds per square inch, pure oxygen atmosphere of the spacesuits this evening.

The International Space Station remains in good condition, ready for the crew to enter on Monday to start several days of maintenance and unloading of supplies. As the crew's waking hours wound down early this morning, Mary Ellen Weber, who will oversee much of the transfer of equipment, and Halsell made some early preparations of the docking system for the eventual entry into the station.

The crew will begin a sleep period at 8:11 a.m. and awaken at 4:11 p.m. for a fourth day in space, a day devoted to the spacewalk. Voss and Williams are planned to begin donning their gear and suits at 6:11 p.m., leading to a predicted exit from Atlantis' airlock hatch at 9:31 p.m. During the spacewalk, Williams' suit will be distinguishable from Voss' suit by red stripes around the legs. The astronauts are scheduled to conclude the spacewalk at 4:01 a.m. Monday.

Atlantis is operating well with flight controllers reporting no problems of significance for any of the mission's activities. The shuttle and station are 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.

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.

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, 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.

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.

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.

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.