Feasibility and Performance of Atmospheric-Breathing Propulsion for Mars Descent

Abstract

Analysis was performed to assess the impact of atmospheric-breathing supersonic retropropulsion as a technology solution for Mars descent. Vehicle models were developed for three architectures, employing an atmospheric-breathing engine for both descent and terminal maneuvers, an atmospheric-breathing engine for descent and rocket engine for the terminal maneuver, and a fully rocket propulsive vehicle. Investigations into design constraints showed the inlet area to dictate convergence for the all atmospheric-breathing architecture. These vehicles were limited by oxidizer ingestion for the terminal maneuver and the reduced propulsive descent timeline. Optimal configurations preferred lower-thrust, lower-propellant-usage designs, which were better able to mitigate the mass penalty of the low thrust-to-weight engine. The terminal rocket architectures were instead limited by rocket thrust, which compensated for marginal deceleration during descent. Optimal configurations tended toward large atmospheric-breathing engine performance over high thrust terminal rocket engines because of the favorable fuel usage. Among all architectures considered, the solely atmospheric-breathing vehicles had the best mass performance, with reductions for all component masses with respect to the terminal rocket engine. The terminal rocket architecture did not exhibit significant performance increase over fully rocket vehicles. This study shows that atmospheric-breathing propulsion has promise for improving Mars descent.