Precision Landing at Mars Using Discrete-Event Drag Modulation

An entry, descent, and landing architecture capable of achieving Mars Science Laboratory-class landed accuracy (within 10 km of target) while delivering a Mars Exploration Rover-class payload to the surface of Mars is presented. The architecture consists of a Mars Exploration Rover-class aeroshell with a rigid, annular drag skirt. Maximum vehicle diameter, including drag skirt, is limited to be compatible with current launch-vehicle fairings. A single drag-skirt jettison event is used to control range during entry. Three-degree-of-freedom trajectory simulation is used in conjunction with Monte Carlo techniques to assess the flight performance of the proposed architecture. Results indicate that landed accuracy is competitive with preflight Mars Science Laboratory estimates, and peak heat rate and integrated heat load are significantly reduced relative to the Mars Exploration Rover entry system. Modeling parachute descent within the onboard guidance algorithm is found to remove range error bias present at touchdown; the addition of a range-based parachute deploy trigger is found to significantly improve landed accuracy.