Every year on May 25, fans of The Hitchhiker’s Guide to the Galaxy celebrate Towel Day. In order to show their appreciation for the books and author Douglas Adams, fans will carry a towel with them, which the guide calls “the most massively useful thing an interstellar hitchhiker can have.”
Even though Adams’ guide is a work of science-fiction, towels came in quite handy for a couple of real-life astronauts on the STS-98 mission in February of 2001. On the first spacewalk of the mission, astronauts Robert Curbeam and Thomas Jones were connecting electrical and data cables and cooling lines. While Curbeam was attaching a cooling line, crystallized ammonia began to leak and get all over his spacesuit. The leak was stopped and Curbeam stayed out in the sun for another half hour to vaporize any ammonia on his suit.
Once the astronauts returned to the shuttle airlock, wet towels were used to clean off the remaining ammonia. Pure ammonia, which is used as a cooling agent in space, is anhydrous, meaning that it contains no water. Therefore the crystallized ammonia would stick to the wet towels and could be safely disposed of. In addition to the towels, the airlock was partially pressurized, vented and repressurized to ensure the crew’s safety.
To learn more about the STS-98 Mission, head over to NASA’s website.