Multibody Modeling and Simulation for Mars Phoenix Entry, Descent, and Landing

Abstract

A multibody flight simulation for the Phoenix Mars Lander was developed that included high-fidelity six-degreeof-freedom rigid-body models for the parachute and lander system. The simulation predicted attitude and rate histories of all bodies throughout the flight. In so doing, a realistic behavior of the descending parachute/lander system dynamics was simulated that allowed assessment of the Phoenix descent performance and identification of sensitivities for landing. This simulation provided a complete end-to-end capability of modeling the entire entry, descent, and landing sequence for the mission. The simulation was used to predict the parachute and lander aerodynamic angles during entry and the response of the lander system to various wind models and windshears. Several different wind models were analyzed to determine which was most effective at exciting vehicle attitude dynamics. The simulation was used to drive a Monte Carlo analysis that provided a statistical evaluation of the performance capability of the Phoenix landing system.entry time Ixx, Iyy, Izz = moments of inertia about the X, Y, and Z axes L = spacecraft landing time M = Mach number = inertial flight-path angle

Landing-Site Dispersion Analysis and Statistical Assessment for the Mars Phoenix Lander

“…Phoenix EDL simulations were performed independently by the EDL systems team using POST [7][8][9][10] and by the navigation team using DSENDS [11]. POST was used for EDL system design, validation, and verification and for analysis performed by the EDL systems team [8,12] during flight operation.…”

End-to-end Mars entry, descent, and landing modeling and simulations for Tianwen-1 guidance, navigation, and control system

“…In the EDL phase, the Tianwen-1 lander sequentially performs trim wing deployment, parachute deployment, heatshield ejection, and backshell separation in the highly uncertain Mars environment [3]. Thus, the dynamics of the EDL phase are complicated and involve multiple bodies with significant interactions [4]. To accurately model the dynamics of the EDL phase, we develop an end-to-end Mars EDL simulation tool for the Tianwen-1 GNC system, including high-fidelity models of the Mars atmosphere, parachute, and lander system.…”