Abstract: Laminated carbon-carbon composites can be used as an ablative material, but they are often prone to delamination under thermally induced interlaminar shear and tension. Graded carbon-carbon composites with a sacrificial or ablative layer that is integral with one or more underlying layers and not fully dense can address these issues and provide other advantages. Such graded carbon-carbon composites can include a densified base layer containing a first portion of a carbonaceous matrix, and an outer ablative layer that is integral with the densified base layer and contains a second portion of the carbonaceous matrix. The carbonaceous matrix in the densified base layer has a first porosity, and the carbonaceous matrix in the outer ablative layer has a second porosity that is higher than that of the densified base layer. Methods for forming graded carbon-carbon composites can include heating a partially densified base layer and a carbonaceous matrix precursor above a carbonization temperature.

Abstract: A robust, chemically, structurally, and thermodynamically compatible ablative gap filler that can be processed with ease is provided. The gap filler uses a carbon phenolic mixture that has nearly the same material property characteristics as the adjacent PICA or carbon phenolic tiles. The gap filler is applied into the gaps using an innovative processing approach that involves preparation of a ‘dry mixture’ of the ingredients, which is then packed manually or robotically (if needed) into the gaps. During the packing process, the dry mixture may be vented, and pressed periodically to ensure that there are no trapped voids. After each gap is adequately filled with the mixture, the assembly is bagged and cured in the oven at about 250 or 300° F. for about 1.5 to 2 hours. The gap filler thereby forms a bond with the adjacent PICA or carbon phenolic tiles, without degrading or modifying the properties at any of the interfaces (e.g., with the tiles, adhesives, substrate, etc.).

Abstract: A pyrolyzing flexible ablator comprising a flexible substrate and a pyrolyzing material that will pyrolize upon exposure to a heat flux greater than 5 W/cm2, the pyrolyzing material being bonded to the flexible substrate.

Abstract: A low-to-medium mass density ablative thermal protection system (TPS) comprises a phenolic-based core member comprising a honeycombed plurality of cells separated by cell walls; and an ablator material comprising a carbonaceous material and a phenolic resin material filling the cells. The ablator material may further comprise silica and phenolic resin microspheres. Embodiments include fabricating the ablative TPS by filling the cells of the core member with a liquid slurry or dry mixture of the ablator material, followed by degassing, drying, and curing of the ablator material.

Abstract: The present invention discloses an insulated reentry heat shield for minimizing heat transfer to a spacecraft structure or the like during atmospheric reentry. The heat shield (10) comprises an outer heat resistant layer (12) including an ablative first material backed by an inner insulating layer (14) including an insulating second material. The outer and inner layers (12, 14) are bonded to one another by a middle layer (16) disposed therebetween. The middle layer is formed by disposing at least one layer of a phenolic loaded third material between the outer and inner layers and heating all three layers simultaneously to remove phenolic volatiles from the middle layer. In one embodiment, the ablative first material is carbon-carbon, the insulating second material is carbon foam, and the phenolic loaded third material is carbon scrim cloth. The present invention also discloses a method for use in constructing a heat shield.

Abstract: An integrated sample return capsule for use in returning materials to Earth from space, such as core samples from other celestial bodies and experiments from orbiting platforms. The sample return capsule incorporates thermal protection, structural integrity and impact mitigation into a single system capable of safely and securely returning the materials without requiring decelerating parachutes. In one embodiment, the integrated sample return capsule includes a forward facing heat shield and a back shell attached to the rear of the heat shield. The heat shield and the back shell define an interior enclosure. The back shell includes an access, such as a door or a removable panel, there through to the interior enclosure. Materials to be returned may be sealed in a sample containment vault, and the sealed vault may be placed into the interior enclosure through the access.