Encyclopedia Astronautica
ATS-4


American communications technology satellite. One launch, 1968.08.10, ATS 4. A launch vehicle failure stranded ATS-4 in a much lower than planned orbit, making the satellite nearly useless.

Although the spacecraft's systems were functional, little data was obtained. Spacecraft: Gravity gradient stabilized, 130 W BOL. Payload: C-band communications package

AKA: Applications Technology Satellite.
Gross mass: 391 kg (862 lb).
Height: 1.80 m (5.90 ft).
First Launch: 1968.08.10.
Number: 1 .

More... - Chronology...


Associated Countries
See also
  • Atlas The Atlas rocket, originally developed as America's first ICBM, was the basis for most early American space exploration and was that country's most successful medium-lift commercial launch vehicle. It launched America's first astronaut into orbit; the first generations of spy satellites; the first lunar orbiters and landers; the first probes to Venus, Mars, Mercury, Jupiter, and Saturn; and was America's most successful commercial launcher of communications satellites. Its innovative stage-and-a-half and 'balloon tank' design provided the best dry-mass fraction of any launch vehicle ever built. It was retired in 2004 after 576 launches in a 47-year career. More...

Associated Launch Vehicles
  • Atlas The Atlas rocket, originally developed as America's first ICBM, was the basis for most early American space exploration and was that country's most successful medium-lift commercial launch vehicle. It launched America's first astronaut into orbit; the first generations of spy satellites; the first lunar orbiters and landers; the first probes to Venus, Mars, Mercury, Jupiter, and Saturn; and was America's most successful commercial launcher of communications satellites. Its innovative stage-and-a-half and 'balloon tank' design provided the best dry-mass fraction of any launch vehicle ever built. It was retired in 2004 after 576 launches in a 47-year career. More...

Associated Manufacturers and Agencies
  • NASA American agency overseeing development of rockets and spacecraft. National Aeronautics and Space Administration, USA, USA. More...
  • NSF American agency overseeing development of spacecraft. National Science Foundation, USA. More...
  • Hughes American manufacturer of rockets, spacecraft, and rocket engines. Hughes Aircraft Co. , USA More...

Associated Programs
  • ATS The Applications Technology Satellite was a project with the purpose of improving other satellites, specifically to enhance the ability of existing and future satellites to provide weather, and communications data and air/sea navigation aids. More...

Bibliography
  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Web Address when accessed: here.
  • Bramscher, Robert G, "A Survey of Launch Vehicle Failures", Spaceflight, 1980, Volume 22, page 351.
  • Lockheed Martin Coporation, Atlas Family Fact Sheets, September 1998.. Web Address when accessed: here.
  • NASA Report, An advanced study of an Application Technology Satellite /ATS-4/ mission, volume I, book 1 Final study report, May - Nov. 1966, Web Address when accessed: here.

Associated Launch Sites
  • Cape Canaveral America's largest launch center, used for all manned launches. Today only six of the 40 launch complexes built here remain in use. Located at or near Cape Canaveral are the Kennedy Space Center on Merritt Island, used by NASA for Saturn V and Space Shuttle launches; Patrick AFB on Cape Canaveral itself, operated the US Department of Defense and handling most other launches; the commercial Spaceport Florida; the air-launched launch vehicle and missile Drop Zone off Mayport, Florida, located at 29.00 N 79.00 W, and an offshore submarine-launched ballistic missile launch area. All of these take advantage of the extensive down-range tracking facilities that once extended from the Cape, through the Caribbean, South Atlantic, and to South Africa and the Indian Ocean. More...
  • Cape Canaveral LC36A Atlas launch complex. Launch site built in 1960 for NASA's Atlas/Centaur development program, and used for launches of that launch vehicle until its retirement. More...

ATS-4 Chronology


1968 August 10 - . 22:33 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC36A. LV Family: Atlas. Launch Vehicle: Atlas Centaur SLV-3C. LV Configuration: SLV-3C Centaur AC-17 / Centaur D-1A 5104C. FAILURE: Centaur oxidizer leak. No restart.. Failed Stage: 2.
  • ATS 4 - . Payload: ATS D. Mass: 391 kg (862 lb). Nation: USA. Agency: NASA Greenbelt. Program: ATS. Class: Technology. Type: Communications technology satellite. Spacecraft: ATS-4. Decay Date: 1968-08-10 . USAF Sat Cat: 3344 . COSPAR: 1968-068A. Apogee: 769 km (477 mi). Perigee: 220 km (130 mi). Inclination: 29.1000 deg. Period: 94.50 min. Applications Technology Satellite that was to have been put into a geosynchronous transfer orbit, instead was left in a nearly-useless LEO orbit. ATS-4 included two cesium contact ion engines. Flight test objectives were to measure thrust and to examine electromagnetic compatibility with other spacecraft subsystems. The 5 cm diameter thrusters were designed to operate at 0.02 kW and provide about 89 microN thrust at about 6700 s specific impulse. The thrusters had the capability to operate at 5 setpoints from 18 to 89 microN. Thrusters were configured so they could be used for East-West station-keeping. Prior to launch, a 5 cm cesium thruster was life tested for 2245 hours at the 67 microN thrust level. However the Centaur upper stage did not achieve a second burn and the spacecraft remained attached to the Centaur in a 218 km by 760 km orbit. It was estimated that the pressure at these altitudes was between 10^-6 and 10^-8 Torr. Each of the two engines was tested on at least two occasions each over the throttling range. Combined test time of the two engines was about 10 hours over a 55 day period. The spacecraft re-entered the atmosphere on October 17, 1968. TheATS-4 flight was the first successful orbital test of an ion engine. There was no evidence of IPS electromagnetic interference related to spacecraft subsystems. Measured values of neutralizer emission current were much less than the ion beam current, implying inadequate neutralization. The spacecraft potential was about -132V which was much different than the anticipated value of about -40V.

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