Three types of missions were planned for ATS: one satellite in a 10,000 km earth orbit to experiment with the gravity gradient stabilization system; two satellites in synchronous (38,300 km) orbits for meteorological, communications and navigation investigation; and two satellites in synchronous orbits using the gravity gradient system to make engineering and technological studies. The ATS were barrel-shaped spacecraft weighing about 320 kg; those equipped for gravity gradient experiments carried 30 m booms that extended like a tight-rope walker's balancing pole to stabilize the spacecraft. The program was managed by NASA's Goddard Space Flight Center. Prime Contractor: Hughes Aircraft Company.
|ATS-2 American communications technology satellite. ATS 2. ATS-2 was placed into an undesirable orbit due to a launch vehicle failure.|
|ATS-3 American communications technology satellite. ATS 3. The goals for ATS-3 included investigations of spin stabilization techniques and VHF and C-band communications experiments.|
|ATS-5 American communications technology satellite.|
|ATS-6 American communications technology satellite. ATS 6. In addition to its technology experiments, ATS-6 became the world's first educational satellite. Communication, Meteorology satellite built by Fairchild for NASA, USA. Launched 1974. Used ATS-6 Bus.|
Applications Technology Satellite; communications and meteorological experiments. Positioned in geosynchronous orbit over the Americas at 151 deg W in 1966-1968?; over the Americas at 149 deg W in 1968-1982; over the Pacific Ocean 170 deg E in 1982-1985 As of 3 September 2001 located at 167.30 deg E drifting at 0.065 deg E per day. As of 2007 Mar 9 located at 59.28W drifting at 0.332E degrees per day.
Communications tests. Positioned in geosynchronous orbit over the Atlantic Ocean at 45 deg W in-100 deg W in 1968-1970; over the Americas at 69 deg W in 1971-1976; over the Americas at 105 deg W in 1977-1998 As of 4 September 2001 located at 105.90 deg W drifting at 0.003 deg W per day. As of 2007 Mar 10 located at 105.23W drifting at 0.006W degrees per day.
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.
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.
An Air Force Titan IIIC boosted NASA's Applications Technology Satellite (ATS-F) into orbit from Cape Canaveral. Built by Application Technology Satellite; experimental communications satellite. The purpose of the ATS-6 flight experiment was to demonstrate north-south stationkeeping of a geosynchronous satellite using two cesium ion engine systems. Thruster development tests included a life test of 2614 hours and 471 cycles. Thruster input power was 0.15 kW, which resulted in a thrust of 4.5 mN at a specific impulse of 2500 s. One of the ion engines operated for about one hour and the other for 92 hours. Both of the engines failed to provide thrust on restart due to discharge chamber cesium flooding. The feed system flooding problem caused overloading of the discharge and high voltage power supplies. This failure mechanism was verified through a series of ground tests. However engine operation demonstrated an absence of EMI related to spacecraft systems, verified predictions of spacecraft potential with engines operating, and demonstrated compatibility with the spacecraft's star tracker. It was found that the ion engines or just the neutralizer could discharge large negative spacecraft potentials at all times. Positioned in geosynchronous orbit over the Americas at 94 deg W in 1974-1975; over the Indian Ocean 35 deg E in 1975-1976; over the Americas at 140 deg W in 1976-1979. As of 2 September 2001 located at 172.56 deg W drifting at 6.144 deg E per day. As of 2007 Mar 8 located at 29.12W drifting at 6.125E degrees per day.