User:Plaws/AMSAT Phase III

AMSAT Phase III is a development program for high earth orbit communications satellites built by, and for the use of, radio amateurs that was begun in 1975. The program was supported by many different AMSAT groups, especially those in Germany, Canada, and the United States. Previous amateur satellites had been in low earth orbit limiting their utility for amateur radio communications The design goals for Phase III were to place the spacecraft in a much higher orbit. Karl Meinzer, DJ4ZC, of AMSAT-DL, the German AMSAT organization, recommended a Molniya orbit which is highly elliptical and has an apogee that favors the northern hemisphere where most amateur radio operators live.

Spacecraft
There have been four Phase III spacecraft launched. Each carried a variety of communication modules supporting both ground-to-ground communications as well as telemetry and telecommand functions. The first, Phase III-A (styled variously as Phase 3A, P3A, etc) was launched on 1980-05-23 at 14:29:39 UTC aboard an Ariane 1 launch vehicle. The launch was unsuccessful.

On 1983-06-16 at 11:59:03 UTC, Phase III-B was launched into orbit on another Ariane 1 launcher. The satellite collided with an upper stage of the launch vehicle after separation and this damaged the propulsion system. As a result, the spacecraft was unable to reach its intended orbit. The satellite was operational however, and upon commissioning, received the designator AMSAT-OSCAR 10. The spacecraft lost all attitude control in 1986 but remained in amateur radio service until 2003.

Phase III-C, a spacecraft identical in most respects to the previous two, launched on an Ariane 44LP on 1988-06-15 at 11:19:01 UTC. Upon commissioning, it received the designation AMSAT-OSCAR 13. It remained in orbit until December, 1996, when the spacecraft's perigee decayed enough to cause the spacecraft to re-enter the atmosphere.

In 2000 (on November 16 at 01:07:07 UTC), the most sophisticated satellite in the Phase III program, Phase 3D, was launched on yet another Ariane, this time a 5G. Upon commissioning, the spacecraft received the designation AMSAT-OSCAR 40. Problems started shortly after launch with some telemetry transmitters not functioning as expected. Finally, in 2004, catastrophic failure, assumed to be an explosion of one of the rocket motor components, took the satellite out of service.