We describe Sherpa - a Strap-on High-altitude Entry Reconnaissance & Precision Aeromaneuver system that utilizes a moving mass system within an entry capsule to land a spacecraft precisely onto the surface of Mars. Sherpa uses two sets of "strap-on" assemblies, one for high-altitude sensing using a terrain imager, and another for agile hypersonic flight using a moving-mass steering device. In this paper we focus on the moving mass system - a steering device that provides an agile trajectory control capability that is mechanically simple, completely internal to the vehicle, has high control authority, and is robust to mechanism failure. The Sherpa system takes a small fraction (5-10%) of the total system mass, and is capable of delivering payloads to within the proximity (～5 km) of a wide variety of landing sites including those at high-altitude (2.5+ km above the reference geoid).
展开▼
