Single-event drag modulated aerocapture at Venus for a small satellite science mission, Year 1

The single-event drag modulated aerocapture delivers the payload to the desired orbit by monitoring the velocity reduction during atmospheric entry continually and releasing the larger drag surface once the desired velocity is achieved. The goal of this study is to identify and address the technology challenges to enable a simple, single-event drag modulated aerocapture at Venus for a small satellite science mission. In particular, there were three key risk-related questions to be addressed in this effort: 1. Is the vehicle stable before, during, and after the single-event jettison? What is the likelihood that the drag skirt could re-contact the vehicle after the jettison? 2. Is the guidance and control algorithm sufficiently robust in achieving the target science orbit despite navigational and atmospheric uncertainties? 3. Can available thermal protection system (TPS) materials maintain acceptable temperature limits on the aerocapture vehicle at Venus? The focus of the first-year effort resulted maturing the drag modulated aerocapture concept at Venus by identifying challenges and addressing them. Of the three key risks, two have been thoroughly addressed. The combined navigation and atmospheric DSENDS trajectory analyses show that this system can feasibly target a science orbit within acceptable limits. The aerothermal analysis shows that mature and well-characterized TPS materials can meet the demands of hypersonic flight at Venus. The TPS selection and sizing provided the mass estimate necessary. The first objective, which focuses on the stability of the delivered payload is the subject of future work. The CFD/6-DOF simulation using CART3-D was used to identify a single skirt as the choice to avoid re-contact between the two bodies, but packaging and stability of the center body will require detailed analysis. A detailed review of simulation setup and assumptions, as well as accurate modeling of the effects of spin-stabilization, will be the main focus in mitigating the stability concerns. Stability concerns will be addressed through ballistic range experiments as well as accurate modeling in year 2.