Tracking and data relay satellite system /TDRSS/

Plans for a new way of providing tracking and data acquisition support for future earth orbital missions, the Tracking and Data Relay Satellite System (TDRSS), are reviewed. This system is to become the principal support facility for all NASA R&D missions below about 5000 km altitude. Current plans call for a 2-satellite system that is to provide upwards of 85% coverage of all orbits above 200 km and 100% coverage above 1200 km.