ATS-5
Spacecraft · USA
Original archive entry. The text, images and links below are kept as they were written.
American communications technology satellite.
The experimental goals of ATS-5 included a demonstration using L-band signals to precisely locate ships, tests of an electric ion engine, evaluation of the attenuation effects on RF signals by rain, and C-band communications tests. However, following the firing of the satellite's apogee kick motor, ATS-5 went into an unplanned flat spin. The vehicle recovered and began spinning about the correct axis, but in the direction opposite that planned. As a result, the spacecraft's gravity gradient booms could not be deployed, and some experiments were not functional. The spacecraft was able to perform some of its experimental goals, and was finally boosted above geostationary orbit at the end of its mission.
The spacecraft had an aluminum structure, and drum mounted solar cells provided 150 W BOL and recharged 2 x 6 Ah NiCd batteries. N2 and N2H4 thrusters provided attitude control, yo-yo despin, and nutation control. The solar arrays were cooled by heat pipes. The spacecraft was originally planned as gravity gradient stabilized.
Payloads included a magnetometer, an ion engine (a 10^-5 lbf resistojet), a C-band communications package, a millimeter wave propagation experiment, and an L-band communications experiment.
Related
- Country
- USA
- Launch Vehicles
- Atlas, Atlas SLV-3C Centaur
- Projects
- ATS
- Launch Sites
- Cape Canaveral, Cape Canaveral LC36A
Chronology
1 event
1969 August 12
11:01 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC36A. LV Family: Atlas. Launch Vehicle: Atlas SLV-3C Centaur.- ATS 5 - .
Payload: ATS E. Mass: 821 kg (1,809 lb). Nation: USA.
Agency: NASA Greenbelt.
Program: ATS.
Class: Technology.
Type: Communications technology satellite. Spacecraft Bus: ATS.
Spacecraft: ATS-5.
Completed Operations Date: 1984-01-01 . USAF Sat Cat: 4068 . COSPAR: 1969-069A. Apogee: 36,024 km (22,384 mi). Perigee: 35,992 km (22,364 mi). Inclination: 14.50 deg. Period: 1,447.40 min.
Applications Technology Satellite; communications tests. Launch vehicle successfully put the payload into a geosynchronous transfer orbit. The spacecraft maneuvered into geostationary orbit at 108 degrees W. The purpose of this flight was to demonstrate North-South Stationkeeping of a geosynchronous satellite. ATS-5 was equipped with an ion engine package identical to that on ATS-4. Once in geosynchronous orbit the spacecraft could not be despun as planned, and thus the spacecraft gravity gradient stabilization could not be implemented. The spacecraft spin rate was about 76 revolutions per minute, and this caused an effective 4g acceleration on the cesium feed system. The high g-loading on the cesium feed system caused flooding of the discharge chamber, and normal operation of the thruster with ion beam extraction could not be performed. The IPS was instead be operated as a neutral plasma source, without high-voltage ion extraction, along with the wire neutralizer to examine spacecraft charging effects. The neutralizer was also operated by itself to provide electron injection for the spacecraft charging experiments. Positioned in geosynchronous orbit over the Americas at 105 deg W in 1969-1977; over the Americas at 70 deg W in 1977-1983. As of 1 September 2001 located at 15.48 deg E drifting at 2.807 deg W per day. As of 2007 Mar 10 located at 111.70E drifting at 2.819W degrees per day.