Effects of weather encounters on zero-lift reentry vehicles

The ABRES Shape Change Code (ASCC80) was used to predict the surface ablation/erosion and associated reentry trajectories for several zero-lift reentry vehicles. The sphere-cone vehicles considered had 0.1 or 0.2 bluntness ratios with solid GE-223 carbon-carbon or ATJ-S graphite nosetips. Reentry into clear air and in two weather environments was considered for each vehicle configuration. Two cases with different initial reentry conditions were studied. The predicted trajectories, nosetip shape change, increase in drag and resulting shortfall, due to hydrometeor erosion, are compared with the clear air results. The results of these predictions indicate a significant effect of weather encounters on reentry vehicle aerodynamics and nosetip design.