Heat Shield Sample, Gemini VIII

This is a fragment of the heat shield of Gemini VIII, which carried astronauts Neil Armstrong and David Scott into orbit on March 16, 1966. They accomplished the first docking in space, but were forced to terminate their mission the same day when a stuck thruster caused the spacecraft to roll out of control. Made by McDonnell Aircraft, the heat shield's base is resin-impregnated fiberglass honeycomb and the outer layer of ablative material is fiberglass honeycomb filled with silicone elastomer. The dish-shaped shield created a shock wave that held off most of the heat during the capsule's reentry in to the Earth's atmosphere. The rest dissipated by ablation--charring and evaporation of the silicone elastomer. Ablative heat shields are not reusable. After the mission, the heat shield was cut up for evaluation and in 1968 NASA gave the pieces to NASM.