High specific-strength C-Zr(O)C / C-ablator TPS for CEV

This Phase I NASA SBIR Proposal seeks to demonstrate a new zero-erosion ablative thermal protection system (TPS) technology that is based upon an ultra-high temperature (UHT) ceramic fiber pre-form / organic ablative matrix composite structure. In this TPS material concept, the "char" phase is pre-engineered UHT zirconium carbide (Zr(O)C) ceramic fiber pre-forms, which have dual functions of high compressive strength of ligaments and non-recession of fiber components after matrix ablation. To increase the pre-form ligament strength and stiffness, Zr(O)C fiber reinforcements will be combined with the high-modulus carbon fibers. MG's ablative TPS are designed to retain their shape in extreme environments, thereby reducing the thickness requirement and lowering the TPS total mass, which will be crucial at high re-entry velocity. MG's new ablator slowly absorbs high levels of energy when ablated at higher temperatures. The ablative carbonaceous phase has been identified by the use of a melamine-formaldehyde and/or polyethylene polymer resin. This selection was based upon its high heat of volatilization and decomposition. At the completion of the Phase I and Phase II program, MG will have fabricated a high specific strength C-Zr(O)C / C-ablator and have demonstrated an completely integrated 5'x5' size TPS with attachment features, operational at > 6000oF.