A thermal stress test was conducted to determine the ability of the GPHS aeroshell 3-D FWPF material to maintain physical and mechanical integrity when exposed to a severe heat flux environment such as would occur from prompt reentry of GPHS modules. The thermal stress test was conducted in the Giant Planetary Facility (GPF) at NASA's Ames Research Center (ARC). In collaboration with Los Alamos Scientific Laboratory (LASL) GPHS project staff, Battelle designed a test model compatible with GPF size requirements. The test model was fabricated by LASL. Battelle designed, fabricated, installed, and checked out a unique strain measuring transducer to fit in the cavity of the test specimen. Preliminary thermal and thermal stress analyses of the test specimen were conducted by Battelle. These analyses showed that the GPF facility could easily reach heating rates that would produce temperatures and stresses in the test specimen of the same order as those computed in the GPHS module aeroshell for prompt reentry.