The surfaces of rocket engine are exposed to high pressure combustion products at temperatures up to 6000°F. Liquid fueled engines direct fuel through heat exchangers to prevent over heating the engine components. While this is effective, the elevated fuel temperatures cause thin layers of coke to be deposited in the heat exchanger channels. Although the amount of coke deposited per mission is not problematic, the evolving practice of reusing rocket engines presents the potential for excessive coke accumulation, which could lead to engine failure. Therefore, there is a need to develop a method to characterize coke layer thickness so that engine lifetimes can be predicted. 

Reaction Systems identified an approach that can rapidly and accurately map very thin layers of coke deposited in the cooling channels. The method can detect coke thicknesses of less than a millionth of an inch. This technology will allow liquid fueled rocket engines to be reused and eliminate potential hazards caused by coke accumulation.