Aerothermodynamics of manned Mars missions

The aerothermodynamic problems associated with the aerobraking of the spacecraft proposed for the manned Mars mission are studied. The propulsive Delta V necessary at departure from earth and Mars and the velocities of the atmospheric entries into the two planets are deduced. It is shown that the propulsive Delta V can be reduced by increasing the entry velocities and that entry velocities up to about 15 km/sec are appropriate at both earth and Mars. L/D values of 0.8 and 2.0 are found to be necessary at earth and Mars, respectively. Density, pressure, and stagnation-point convective-heat-transfer rates are calculated for the typical aerobraking flights. Assuming the shock layer flow to be in equilibrium, the stagnation-point radiative-heat-transfer rates are calculated to be larger than the convective-heat-transfer rates. The possible impact of ablation, turbulence, and nonequilibrium are discussed.