Improved Mars Helicopter Aerodynamic Rotor Model for Comprehensive Analyses

The Mars Helicopter is part of the NASA Mars 2020 rover mission scheduled to launch in July of 2020. Its goal is to demonstrate the viability and potential of heavier-than-air vehicles in the Martian atmosphere. The low density of the Martian atmosphere and the relatively small-scale rotor result in flows with very low Reynolds number, reducing the lifting force and lifting efficiency, respectively. This paper describes the generation of the improved Mars Helicopter aerodynamic rotor model. The goal is to generate a performance model for the Mars Helicopter rotor using a free wake analysis in CAMRADII. The improvements in the analysis are twofold and are expanded on from two prior publications. First, the fidelity of the simulations is increased by performing higher-order time-accurate OVERFLOW simulations allowing for higher-accuracy aerodynamic coefficients and a better understanding of the boundary-layer behavior. Second, a model is generated for the testing conditions in the 25-ft-diam Space Simulator at the Jet Propulsion Laboratory, allowing for better correlation of rotor performance figures. The higher temperatures in the experiment are expected to give conservative performance estimates, as they give rise to an increase in speed of sound and decrease in observed Reynolds numbers.