An experimental investigation was made to determine the resistance to heat penetration and deformations or buckling of three ablation materials during simulated exposure to lifting vehicle afterbody heating conditions. The ablation materials, which were bonded to inconel cones, were subjected to convective heating at cold-wall heating rates ranging from 4 to 40 Btu/sq ft-sec (45 to 454 kW/sq m) in arc jet streams of air and nitrogen. The ablation materials tested were a molded epoxy-based composite and a silicone elastomeric with and without honeycomb reinforcement. For the test conditions of the investigation, models with the epoxy-based composite and the unreinforced silicone elastomeric developed buckles in the ablation material; two models of the epoxy-based composite failed catastrophically. The honeycomb reinforcement in the silicone elastomeric was beneficial in restraining thermal expansion and maintaining char integrity. Except for tests in nitrogen, the silicone elastomerics provided the best resistance to heat penetration.