Aerodynamics of Stardust Sample Return Capsule

Successful return of interstellar dust and cometary material by the Stardus t Sample Return Capsule requires an accurate description of the Earth entry vehicle's aerodynamics. This description must span the hypersonic-rarefied , hypersonic-continuum, supersonic, transonic, and subsonic flow regimes. D ata from numerous sources are compiled to accomplish this objective. These include direct simulation Monte Carlo analyses, thermochemical nonequilibri um computational fluid dynamics, transonic computational fluid dynamics, ex isting wind-tunnel data, and new wind-tunnel data. Four observations are hi ghlighted: 1) a static instability is revealed in the free-molecular and ea rly transitional flow regimes due to aft location of the vehicle's center o f gravity, 2) the aerodynamics across the hypersonic regime are compared wi th the Newtonian how approximation and a correlation between the accuracy o f the Newtonian flow assumption and the sonic line position is noted, 3) th e primary effect of shape change due to ablation is shown to be a reduction in drag, and 4) a subsonic dynamic instability is revealed that necessitat ed the addition of a stabilizing drogue parachute.