Conceptual Modeling of Supersonic Retropropulsion Flow Interactions and Relationships to System Performance

Abstract

Supersonic retropropulsion is an entry, descent, and landing technology applicable to and potentially enabling high-mass missions required for advanced robotic and human exploration on the surface of Mars. For conceptual design, it is necessary to understand the significance of retropropulsion configuration on an entry vehicle’s static aerodynamic characteristics and the relation of this configuration to other vehicle performance metrics. This investigation developed an approximate model for the supersonic retropropulsion flowfield to assist in evaluating the impact of design choices on the vehicle’s drag characteristics for flight-relevant conditions and scales. This model was used to explore the impact of operating conditions, required propulsion system performance, propulsion system composition, and vehicle configuration on the integrated aerodynamic drag characteristics of full-scale vehicles for Mars entry, descent, and landing. The forebody aerodynamic drag and axial force characteristics of vehicles at two different mission scales were shown to be insensitive to major trades common to conceptual design. This work concluded that conceptual design trades of supersonic retropropulsion may be evaluated using engineering models or assumptions with minimal support from high-fidelity computational aerodynamic analyses.