Analyses of Roll Damping Coefficients in Hypersonic Rarefied Flows

Abstract

At Japan Aerospace Exploration Agency (JAXA), several sample return missions that use Hayabusa(HYB)-type sample return capsules (SRCs) have been proposed. Since HYB-type SRCs use spin-stabilization scheme during reentry, the determination of spin rate deceleration during reentry is important. However, roll damping effect, which may affect spin stability prerequisite, is not well-known for the capsules. In this work, we develop a numerical simulation scheme for roll damping coefficients, and investigate rarefaction effect and dependence of the coefficients on size, spin rate, and surface accommodation for the purpose of improving the reliability of attitude stability especially in rarefied flow regime. Finally, we discuss the feasibility of measurements for rarefied roll damping phenomena in a ground test facility.