Self-perspiration garment for extravehicular activity improves skin cooling effects without raising humidity

• Published in: Acta Astronautica Vol. 104; no. 1; pp. 260 - 265
• Main Authors: Tanaka, Kunihiko, Nakamura, Koji, Katafuchi, Tetsuro
• Format: Journal Article
• Language: English; Japanese
• Published: Elsevier Ltd 01.11.2014; Elsevier BV
• Subjects: Extravehicular mobility unit; Heat conduction; Humidity; Liquid cooling and ventilation garment; Perspiration; Heat conduction; EVA; Humidity; Perspiration; LCVG; EMU; Extravehicular mobility unit; Liquid cooling and ventilation garment; SPEC
• ISSN: 0094-5765; 1879-2030
• DOI: 10.1016/j.actaastro.2014.08.009

The current U.S. extravehicular activity (EVA) suit in space includes liquid cooling and ventilation garment (LCVG) to control thermal condition. Tubes knitted in LCVG for flowing water interrupt evaporation of perspiration, and astronauts feel discomfort. In the present study, we hypothesized that a self-perspiration garment would effectively lower the skin temperature without raising humidity in the garment. Thus, we developed and examined the effects of the garment. Eight healthy subjects were studied with a cyclic ergometer of 30, 60 90 and 120W loading for 3min each. Skin temperature and humidity on the back were measured continuously. Subjects wore and tested three types of garments i.e., a spandex wear without any cooling device (Normal), a simulated LCVG (s-LCVG) or the spandex wear knitted a vinyl tube for flowing water, and the spandex wear with a tube, which flows water and self-perspiration with oozing water for evaporative cooling (SPEC). All measurements were reached to steady state 2–3min after the setting. The s-LCVG decreased skin temperature 0.39±0.14°C during 12min of cooling. With SPEC, skin temperature did not decrease significantly until 6–9min after starting the cooling. However, the temperature decreased rapidly and significantly after that, and finally decreased 1.59±0.32°C. Humidity in the SPEC was significantly lower than that in s-LCVG. SPEC was effective for lowering skin temperature without raising humidity in the garment. The concept is expected to use as a better cooling system during EVA. •A new concept of cooling garments for extravehicular activity space suit.•The garment itself sweats, and the evaporation helps to cool the body.•The body is effectively cooled during the exercise.•Humidity in the garment is lower than that of the current cooling suit.