The Near Spacecraft Telecommunications System

n X-band telecommunications system developed for the Near Earth Asteroid Rendezvous (NEAR) spacecraft represents an unmatched combination of performance, innovation, and cost-effectiveness for a deep space mission. It centers about two redundant X-band transponder systems that provide the command, telemetry, and tracking functions. Despite a 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. Postlaunch measurements have verified that in-flight performance closely matches predicted performance. (