Apr 7 2009
From The Space Library
NASA announced the selection of the Avcoat ablator system for the Orion crew module’s thermal protection system at the base of the craft. During reentry into Earth’s atmosphere, the base of the spacecraft would endure more heat than any other area of Orion, but the Avcoat system would enable the base to erode, or “ablate,” in a controlled way, transporting heat away from the crew module during its descent. Over a period of three years, NASA’s Orion Thermal Protection System Advanced Development Project had considered eight different candidate materials before choosing the two final candidates—Phenolic Impregnated Carbon Ablator (PICA) and Avcoat, both of which had proven successful in space missions. NASA had used Avcoat for the Apollo capsule heat shield and on select regions of the Space Shuttle’s orbiter in its earliest flights and had resumed production of Avcoat for the study. Avcoat was made of silica fibers with an epoxy-novalic resin filled in a fiberglass-phenolic honeycomb. NASA engineers had manufactured it directly onto the heat-shield substructure. Unlike Avcoat, PICA was manufactured in blocks and attached to the vehicle after fabrication. NASA had used PICA on its first robotic space mission dedicated to exploring the comet Stardust, the first mission to return samples since Apollo. Project engineers had performed rigorous thermal, structural, and environmental testing on Avcoat and PICA, comparing the two materials’ mass, thermal and structural performance, life-cycle costs, ease of manufacturing, reliability, and certification challenges. NASA and Orion’s prime contractor Lockheed Martin ultimately chose Avcoat as the more robust, reliable, and mature system.
NASA, “NASA Selects Material for Orion Spacecraft Heat Shield,” news release 09-080, 7 April 2009, http://www.nasa.gov/home/hqnews/2009/apr/HQ_09-080_Orion_Heat_Shield.html (accessed 17 May 2011).
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