A new lightweight ablator was fabricated by the infiltration of a polyimide resin into a porous carbon material having three-dimensional network and open cell structure. In order to evaluate the performance of the ablator, the thermal response and recession resistance were evaluated using an arc wind tunnel. These properties were discussed from the viewpoint of the cell sizes of porous carbon material. With a decrease in the cell size, internal temperature of the ablator became lower. Microstructural observations revealed that the three-dimensional network structure of the ablator, which originates from the porous carbon preform, was maintained after the heating tests. Consequently, the recession resistance was better than those of existing ablators fabricated from carbon-fiber-based preform.
