Time Domain Simulation of the NASA Crew Launch Vehicle

Abstract

The NASA Crew Launch Vehicle is a two-stage orbital launcher designed to meet NASA’s current as well as future needs for human space flight. In order to free the designers to explore more possibilities during the design phase, a need exists for the ability to quickly perform simulation on both the baseline vehicle as well as the vehicle after proposed changes due to mission planning, vehicle configuration and avionics changes, proposed new guidance and control algorithms, and any other contingencies the designers may wish to consider. Further, after the vehicle is designed and built, the need will remain for such analysis in the event of future mission planning. An easily reconfigurable, modular, nonlinear six-degree-of-freedom simulation matching NASA Marshall’s in-house highfidelity simulator is created with the ability to quickly perform simulation and analysis of the Crew Launch Vehicle throughout the entire launch profile. Simulation results are presented and discussed, and an example simulation to demonstrate the need for ground vibration testing is shown. I. Introduction HE United States National Aeronautics and Space Administration (NASA) has committed to building the ARES I Crew Launch Vehicle as the man-rated launcher to support the implementation of the Vision for Space Exploration 1 . Preliminary Guidance, Navigation, and Control (GNC these analyses assumed there was insufficient cross-coupling of the vehicle axes to affect stability results. SAVANT uses fully coupled nonlinear equations of motion to run a time-domain simulation to arrive at specific operating points where frequency results are desired. SAVANT is capable of generating both time domain and frequency domain information of both the vehicle integrated stack and Upper Stage flight during ascent flight phases. The tool is used to provide vehicle system and component analysis involving system data for multiple Design Analysis Cycles (DAC) and is able to simulate the effects of component and algorithm modifications in terms of flight performance and robustness requirements.