The aerothermodynamic environments encountered by a sample return capsule for the Jupiter Trojan sample return mission, where atmospheric reentry velocities are higher than 14 km/s, are assessed in experimental and numerical approaches. Computational-fluid-dynamic calculations coupled with radiative heat transfer calculations were conducted for the flowfields around the capsule, while the absolute intensity of radiative heat transfer rates was measured by using a shock tube which is capable of generating shock waves at a velocity higher than 14 km/s. Computational-fluiddynamic calculations were conducted at representative flight points along the reentry trajectory with taking account of radiative heat transfer in the shock layer ahead of the capsule. The convective and the radiative heat transfer rates calculated by radiation-coupled flowfield calculations are compared with those obtained by the semi-empirical formulas. The experimental results agree well with the numerical predictions, suggesting that the radiative heat transfer rate amounts to one third or more of the total heat transfer rate at the stagnation point of the capsule. The numerical and experimental results show considerable impacts of the radiative heat transfer on the flow properties in the shock layer.
