DEEP IMPACT: ACS FAULT TOLERANCE IN A COMET CRITICAL ENCOUNTER

摘要

The Deep Impact Project is a NASA Discovery mission to explore cometary science. A mother-daughter dual spacecraft, the Flyby and the Impactor, will launch in January 2004 to intercept comet Tempel-1 on July 4, 2005 as Tempel-1 swings around the Earth and the Sun in its 5.5-year heliocentric orbit. The near comet environment is particularly hazardous and poses a strong challenge for spacecraft and navigation design. Consequently, the mission objective and encounter scenario require a fault tolerant and autonomously recovering design for both spacecraft. This paper describes the overall fault protection architecture for the Flyby and Impactor with special attention to attitude determination and control fault protection design.