Excerpt from the Apollo 11 transcript. NASA.
One hundred and 31 hours, 42 minutes, and 30 seconds into the mission, the crew of Apollo 11 was reunited and preparing for the trans earth injection burn that would send them out of the Moon’s orbit and on a path back home. Command Module Mike Collins was still in his pressure suit — mission rules said the astronauts much be suited when redocking the Command and Lunar modules — and was getting ready to take it off for the TEI burn when Commander Neil Armstrong asked, “You ready for your underwear? Mike - you ready for your underwear? You ready for your underwear?” It turns out the underwear in question is the Liquid Cooled Garment, a brilliant piece of engineering born of necessity, and the first time the human biothermal processes was integral to a suit.
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