THE NEAR SPACECRAFT RF TELECOMMUNICATIONS SYSTEM

An X-band telecommunications system developed for the Near Earth Aster oid Rendezvous (NEAR) spacecraft represents an unmatched combination o f performance, innovation, and cost-effectiveness for a deep space mis sion. It centers about two redundant X-band transponder systems that p rovide 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 develo pments in transponder hardware, an X-band solid-state power amplifier (a deep space ''first''), and efficient microstrip patch antennas. Dur ing spacecraft emergencies, a microstrip fanbeam antenna is used as pa rt of a unique Earth acquisition algorithm. Postlaunch measurements ha ve verified that in-flight performance closely matches predicted perfo rmance.