Advanced Hypersonic Entry Guidance for Mars Pinpoint Landing

Hypersonic entry guidance technology is being developed to support a broad range of future Mars missions. The goal is to develop guidance technology that, in conjunction with other entry, descent, and landing (EDL) technologies, will allow greater landing accuracy, as well as access to higher elevation landing sites, than currently achievable. The guidance technology should be applicable to capsule-type landers, but also higher lift-to-drag (L/D) and ballistic coefficient configurations that will be required for landing higher mass and volume payloads. Our guidance algorithm is based on the concept of planning and tracking drag, and extends the state of the art represented by the entry guidance algorithm of the Space Shuttle Orbiter. Modifications to the planner have been introduced to extend its applicability to low L/D capsules. Final phase position guidance logic has been developed to improve the parachute deployment state control. The algorithm has been tested in simulated flight for a low L/D capsule and a mid L/D ellipsled. The results demonstrate the effectiveness and versatility of the guidance algorithm. The guidance technology is also applicable for landing missions to other atmospherebearing planets and satellites.