A SMART spacesuit should stop astronauts on space-walks getting hot under the
collar. Although the temperature in space is a decidedly frosty 2.7 kelvin,
astronauts working under intense sunlight can get uncomfortably hot鈥攐r
distinctly chilly in the shade.
The answer, says Edward Hodgson of Hamilton Sundstrand Space Systems in
Windsor Locks, Connecticut, is a spacesuit whose material can change the way it
conducts and radiates heat. 鈥淲e want astronauts to be able to lose heat by
sweating as normal and still remain comfortable,鈥� he says. Today鈥檚 spacesuits
have cumbersome fluid-based cooling mechanisms.
If you go outside on a cold day without a jacket, you will lose heat at about
500 watts. Obviously, you鈥檒l give off a lot less heat sitting out on a baking
hot day, maybe 200 watts, mainly through sweating. Hodgson wants a spacesuit
that will radiate heat at somewhere between 50 and 1000 watts. 鈥淚f we get that
good a range, it should address conditions in space,鈥� he says.
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Hodgson鈥檚 spacesuit鈥攆unded by NASA鈥攔egulates how much infrared
radiation the astronaut loses, and also changes the suit鈥檚 ability to insulate
by varying its thickness. The fabric will contain electrochromic polymer fibres
that can alter their absorption of infrared radiation from the astronaut鈥檚 skin
when a small voltage is applied. Between the fabric sheets, Hodgson plans to lay
down polymer-based artificial muscles that expand or contract when a voltage is
applied. The layers are pushed further apart to make the spacesuit thicker and
more insulating when it is cold, and can be pulled closer together when the
astronaut gets too hot.
Hodgson believes that his work will one day come in handy for fashion
designers on Earth, helping people to stay comfortable while they move in and
out of warmer or colder areas.
