Analysis of Hypersonic Tip-Off Rates for Venus Aerocapture

Aerocapture is an innovative aeroassist maneuver that has the potential to greatly reduce the fuel and subsequent mass required in order to enter orbit or land on a planetary body. One such method of aerocapture utilizes a discrete drag modulation event in order to alter the vehicle's ballistic coefficient as a control method. However, the dynamics of the hypersonic jettison event are largely unexplored in literature, particularly surrounding an off-nominal separation event. This paper investigates the tip-off dynamics of hypersonic vehicle separation during planetary aerocapture as well as the risk of recontact due to suction between the skirt and the probe. Venus is selected in order to analyze the dynamics in the most challenging environment. Initial tip-off angles and angular rates are applied in order to assess the risk of vehicle recontact and analyze the resulting dynamics of the probe in flight. Additionally, following a series of scaled ballistic range tests conducted as part of the Venus mission concept development, recontact was observed between the skirt and the probe during the separation events. These tests were recreated in the inviscid CFD environment and compared to the real flight test results.