Stability of a Mechanically Deployed Aerodynamic Decelerator

The Venus In-Situ Explorer (VISE) Mission addresses the highest priority science questions within the Venus community outlined in the National Research Council’s Decadal Survey. The heritage Venus atmospheric entry system architecture, a 45 degree sphere-cone rigid aeroshell with a carbon phenolic thermal protection system may no longer be the preferred entry system architecture compared to other viable alternatives being explored at NASA. A mechanically-deployed aerodynamic decelerator, known as the Adaptive Deployable Entry and Placement Technology (ADEPT), is an entry system alternative that can provide key operational benefits such as deceleration load reduction and risk reduction compared to a rigid aeroshell. ADEPT is attempting to determine whether the currently proposed entry vehicle is stable enough to safely reach Mach 0.8 and deploy a subsonic parachute. Although the deceleration profile will be much smaller for this entry vehicle compared to previous Venus missions, there are stability concerns for 70 degree sphere cone vehicles that need addressing. This paper will focus on understanding the underlying factors that drive the stability of ADEPT. Monte Carlo analyses were used to determine the impact of the dynamic derivatives, winds, and spin stabilizing the ADEPT entry vehicle on the ability to reach a subsonic parachute deploy.

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