writes "NASA said it will this week move some of the larger – 46 lb — mirror segments of its future James Webb Space Telescope into a cryogenic test facility that will freeze the mirrors to -414 degrees Fahrenheit. Specifically NASA will freeze six of the 18 Webb telescope mirror segments at the X-ray and Cryogenic Facility, or XRCF, at NASA's Marshall Space Flight Center in Huntsville, Ala., in a test to ensure the critical mirrors can withstand the extreme space environments. All 18 segments will eventually be tested at the site. The test chamber takes approximately five days to cool a mirror segment to cryogenic temperatures.
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