Abstract: A method of applying sealant to a narrow, deep gap in a surface includes covering the gap to form a covered channel, inserting a flared end of a dispensing nozzle into the covered gap at a first location, and applying a vacuum to the covered gap at a second location while using the nozzle to inject the sealant into the gap at the first location. This method may be used to seal gaps between ablative elements of a heat shield.

Abstract: A thermal protection paste as described herein can be used by itself, or impregnated into a high temperature resistant fabric to form a repair patch, to repair a thermal protection structure. The paste includes a ceramic composition that includes ceramic material having at least a first controlled particle size and a second controlled particle size that is larger than the first controlled particle size. The ceramic composition is mixed into a high temperature ceramic precursor resin to form the paste. The paste (or patch) is applied to the structure under repair and initially heated to cure the paste and to secure it in place. When the paste and/or patch is cured, it becomes a cross-linked polymer having high thermal protection characteristics. When the paste is exposed to very high temperature, e.g., spacecraft reentry temperatures, it pyrolizes and retains its high thermal protection characteristics.