InSight Entry, Descent, and Landing Postflight Performance Assessment

Abstract

On 26 November 2018, the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander successfully touched down on the surface of Mars. Program to Optimize Simulated Trajectories II (POST2) of NASA Langley Research Center was used during both project development and flight operations to assess the entry, descent, and landing (EDL) vehicle performance against related requirements across the expected range of possible environmental and spacecraft conditions. During flight operations, these analyses were used to evaluate the need for updating flight software EDL parameters and the effects of executing a trajectory correction maneuver. Therefore, the NASA Langley Research Center POST2 simulation had a critical role during the cruise, approach, and ultimately EDL phases of the mission. This paper presents the results of the final pre- and post-EDL flight performance assessments. A summary of the reconstructed “as-flown” trajectory with a comparison of key EDL metrics to the nominal and three-sigma bound pre-EDL predictions is also provided. Emphasis on the trajectory between entry interface and parachute deploy is provided, as this is the period during which deviations from the pre-EDL prediction occurred. The postflight assessment provides important verification of the POST2 models and analysis techniques used for InSight, providing critical feedforward information to future lander missions.