This is one of the coolest demonstrations ever: NASA’s new Common Extensible Cryogenic Engine for the lunar lander gets icicles on its rim while burning at 5,000 degrees Fahrenheit. How is this stunning feat possible? The CECE—developed by Pratt & Whitney Rocketdyne and NASA—is fueled by liquid oxygen and liquid hydrogen. All the engine components are super-cooled, so when vapor comes out of the burning of the oxygen and the hydrogen and touches the rim of the cryogenic engine, it transforms into ice instantly.

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Ice Forming at 5,000 Degrees Fahrenheit On NASA’s New Lunar Lander Engine [Science]