Closed-Loop Simulations of Human-Scale Mars Lander Descent Trajectories on Frontier
Gabriel Nastac, Zachary Ernst, Alexandra M. Hickey, Aaron Walden, Kevin Jacobson, William T. Jones, Eric J. Nielsen, Boris Diskin, Li Wang, Ashley M. Korzun, Patrick Moran, Hayden V. Dean, Bradford E. Robertson, Dimitri N. Mavris
Abstract
A computational campaign was performed to run high-fidelity, free-flight simulations of a human-scale Mars lander concept vehicle decelerating under retropropulsion with closed-loop flight control through the Martian atmosphere. A novel approach is used to couple computational fluid dynamics (CFD) software with a mature flight mechanics package, where the two applications communicate in real-time across two geographically-dispersed computational facilities. The CFD is performed on the Frontier exascale system located at Oak Ridge National Laboratory, and the flight mechanics are executed on a system located at NASA Langley Research Center. In the current campaign, CFD is performed using finite-rate chemistry to account for the interactions between the LOX/CH4 engines and the CO2 Martian atmosphere. A simulation of a closed-loop main engine throttling and RCS actuation is presented, demonstrating that the vehicle and model are able to maintain stability in a long-duration CFD-in-the-loop flight simulation. Comparisons are made to a reduced order model ignoring aero-propulsive interactions.