Tuesday, August 26, 2008

Funky thermostat film for spacecrafts

You may remember that keeping our antarctic instrumentation at a constant and not-too low operating temperatures is a major challenge. Some time ago I posted about the heating / insulation strategy we implemented in last year's prototype stations. I'm planning to write a short piece on how that strategy worked out in the next couple of weeks.

The subject of today's post is an innovation in thermostat technology that has just been presented at the 236th American Chemical Society' National Meeting in Philadelphia, and that was brought to my attention by the BBC News website.

Spacecraft have a serious problem with temperature regulation, as they operate in blazing sunlight, in the cold shadow of the Earth, or in even more extreme conditions closer or further away from the Sun. As operating conditions vary, so does the amount of heat generated by the onboard electronics.

For large spacecraft, [temperature control] is done with mechanical louvers—basically glorified window blinds—that open and close to allow in or reflect heat. But as satellites get smaller, these systems get too heavy and bulky. - Prasanna Chandrasekhar of Ashwin-Ushas, an American tehnology firm


Chadrasekhar and his team have developed a "skin" that can be placed on a spacecraft to actively control the amount of heat that it radiate by controlling its emissivity.

Polymers in the skin change their emissivity when electricity is applied to them, retaining heat in cold conditions and radiating it away in hot ones. That leads to an active temperature control that can be maintained with very little power.

The skin is just a few tenths of a millimetre thick, has been tested to withstand the rigours of the vacuum and temperature extremes of space, and can be bent and cut to fit craft of any shape without losing its properties.

Would such material be useful in Antarctic conditions, which are much less extreme than those experienced in outer space ? The answer will depend on the amount of energy required to power the emissivity-regulating skin.

Energy is a serious problem in Antarctica given the duration of the winter night. Should the new skin system be as low power and low-cost as announced at the conference, then its use in Antarctica may well be possible. We shall be keeping a lookout for updates on this product!

No comments: