Space technology three: mission overview and spacecraft concept description

Abstract Space Technology Three (ST3), the third NASA New Millennium Program space technology mission, is focused on validation of key technologies for future separated spacecraft interferometers, such as Terrestrial Planet Finder and the Micro-Arcsecond X-ray Imaging Mission. The main technologies to be demonstrated are autonomous formation flying (AFF) and separated spacecraft interferometry (SSI). This mission uses two spacecraft called the Combiner and Collector, launched together, to validate these technologies. After on-orbit checkout, the spacecraft separate and are maintained within a range of 50– 1000 m . The AFF sensors and control capabilities are validated over a 2 month period followed by three months of SSI operations. Launch into an Earth-trailing heliocentric orbit is tentatively planned for March 2005 on a Delta II 7325. JPL is responsible for formation flying sensors and the interferometer instruments. Ball, selected as ST3 prime and working with JPL, provides the two spacecraft, system integration and test, and operations over the six-month mission duration. This paper summarizes the baseline mission concept and describes the spacecraft bus design in more detail, as defined at the start of the program in November 1999.