Drag modulation flight control for aerocapture

Hypersonic deployable aerodynamic devices, both rigid and inflatable, have the potential to enable a broad spectrum of next-generation aeroassist missions by mitigating shape and size constraints on aeroassist vehicles and providing an in-flight reconfiguration capability. Such a capability provides new options for flight control during atmospheric flight, such as drag modulation. Drag modulation is an attractive flight control option for future aerocapture missions because it requires only minimal additional system complexity for vehicles with deployable aerodynamic devices, in contrast to more conventional lift-modulation steering methods. This study expands upon previous aerocapture drag modulation studies by extending the analysis of single-event jettison systems to Earth and Mars. A single-event jettison guidance algorithm was developed and used to evaluate the feasibility of real-time targeting of apoapsis altitude during flight. Results indicate that sufficiently large ballistic coefficient ratios provide adequate aerodynamic and guided corridors for future aerocapture missions. While the preliminary guidance algorithm demonstrates only modest insertion accuracy, this level of accuracy may be tolerable for certain missions.