Aeroheating Environments for a Mars Smart Lander

Computational predictions of the Mars Smart Lander forebody aeroheating environments are given for a direct entry trajectory. The solutions were obtained using an eight-species gas in thermal and chemical nonequilibrium with a radiative-equilibrium wall-temperature boundary condition. Select wind-tunnel data are presented from tests at NASA Langley Research Center. Turbulence effects are included to account for both smooth body transition and turbulence caused by heat-shield penetrations. Natural transition is based on a momentum-thickness Reynolds number value of 200. The effects of heat-shield penetrations on turbulence are estimated from wind-tunnel tests of various cavity sizes and locations. Both natural transition and heat-shield penetrations are predicted to cause turbulence before the nominal trajectory peak heating time. Laminar and turbulent computational predictions along the trajectory are used to estimate heat rates and loads. The predicted peak turbulent beat rate of 63 W/cm2 on the heat-shield leeward flank is 70% higher than the laminar peak. The maximum integrated heat load for a fully turbulent heat pulse is 38% higher than the maximum laminar load. The predicted heating environments, including uncertainty factors, will be used to design a thermal protection system.