Entry Vehicle Control System Design for the Mars Smart Lander

The NASA Langley Research Center, in cooper ation with the Jet Propulsion Laboratory, parti cipated in a preliminary design study of the Entry, D escent and Landing phase for the Mars Smart Lander Project. This concept uti lizes advances in Guidance, Navigation and Control technology to significantly reduce u ncertainty in the vehicle landed locatio n on the Mars surface. A candidate entry vehicle co ntroller based on the Reaction Control System controller for the Apollo Lunar Excu rsion Module digital autopilot is proposed for use in the entry vehicle attitude control. A slight modification to the phas e plane controller is used to reduce jet -firing chattering while maintaining good control response for the Martian entry probe application. The controller pe rformance is demonstrated in a six -degree -of -freedom simulation with represent ative aerodynamics. Nomenclature