Experimental and numerical study of the Mars Pathfinder vehicle

An experimental and numerical study on the Mars Pathfinder aeroshell vehicle has been carried out in the framework of an agreement between ONERA and NASA. The experimental work was performed in the ONERA R5Ch hypersonic wind tunnel. Flowfield visualizations and heat-flux measurements along the model have been obtained. Numerical simulations have been performed at ONERA with the Reynolds-Averaged Navier–Stokes (RANS) solver NASCA and at NASA with a Direct Simulation Monte Carlo (DSMC) code. The flowfield structure is correctly reproduced by both computations. The location of the bow shock is well predicted, as well as the expansion waves emanating from the end of the forebody cone. Both computations also predict the same extension of the separation bubble in the base flow region of the model. Measured and calculated heat-flux distributions along the model have been compared. Both computations give similar results, except for the prediction of the heat-flux level on the afterbody cone. But computations overpredict the measured heat-flux values on the forebody and the model sting: the value of the stagnation point is overestimated at 28% and the average sting level at 35%.