Telecommunications system technologies for the near spacecraft

Abstract The launch of the Near Earth Asteroid Rendezvous (NEAR) spacecraft on February 17, 1996 was the first in NASA's series of Discovery-class missions. The spacecraft is designed to rendezvous with and eventually orbit the asteroid 433 Eros. The spacecraft telecommunications system is centered about two redundant X-band transponder systems that provide the command, telemetry, and tracking functions. Despite a very tight development schedule, a significant amount of new technology has been used in the system. Included in the design are the most recent developments in transponder hardware, an X-band solid state power amplifier (a deep space “first”), and efficient microstrip patch antennas. During spacecraft emergencies, a microstrip fanbeam antenna is used as part of a unique earth acquisition algorithm. Potential areas for future technology improvements are also discussed.