Conceptual Modeling of Drag-Augmented Supersonic Retropropulsion for Mars Entry, Descent, and Landing

The development of new decelerator technologies will be required as the payload mass for future Mars landing missions increases beyond the current state-of-the-art capability. This study examines the potential for supersonic retropropulsion applied on entry, descent, and landing vehicles to increase the landed payload mass. This study describes the development of a model characterizing the drag augmentation capabilities of peripheral-nozzle supersonic retropropulsion flow interactions. The model captures the dominant flow physics of pressure conservation through shock cascade structures and predicts an increase in the drag coefficient over the nominal drag coefficient of a 70deg sphere-cone aeroshell by 14% at high Mach numbers. This study also describes drag-augmented supersonic retropropulsion operation concepts for use in Mars entry, descent, and landing. Drag-augmented supersonic retropropulsion is found to be most effective when used in the region of maximum freestream dynamic pressure. The vehicle dry mass is increased by 47% over the reference ballistic trajectory. The region of influence for aerodynamic-propulsive interactions is identified for a set of constant-thrust supersonic retropropulsion trajectories. A hybrid concept combining supersonic retropropulsion and an inflatable aerodynamic decelerator is found to be capable of providing vehicle dry masses that are 707% larger than the baseline vehicle studied.