‘Sunshield’ to protect space telescope from extremes of heat, cold

November 13th, 2008 - 2:32 pm ICT by IANS  

Washington, Nov 13 (IANS) Engineers have designed a ‘Sunshield’ to protect NASA’s James Webb space telescope from extremes of heat and cold, radiation and small debris. Besides, the ‘Sunshield’ would also block solar heat to allow its cameras and instruments to operate optimally at 1.6 million km from the earth in 2013.

A satellite has to withstand the icy cold and the intense heat and radiation of a solar flare in space, which ranges between a super-hot 127 degrees Celsius and a frigid minus 243.

Besides, the ‘Sunshield’ will be bombarded with sand-like grains and radiation in space. It has to stand up against those things, as well as tension and ageing under the extreme space environments.

“The Sunshield’s ‘ageing’ occurs from extreme sunburn,” said Mark Clampin, NASA’s project scientist at Goddard Space Flight Centre.

Blocking light and heat from the sun will keep the observatory operating at cryogenic (cold) temperatures, enabling its infrared sensors to see distant galaxies, early stars, and planetary systems, said a NASA release.

That is important because infrared sensors actually measure the heat given off from far away galaxies and stars. Shaded and protected from the Sun, the Sunshield allows the telescope to cool down to a minus 233 Celsius.

Any warmer than that and the heat given off from the telescope would corrupt the data.

Jonathan Gardner, NASA’s deputy senior project scientist said “infrared is heat radiation. In order to see the faint glow of infrared heat from distant stars and galaxies, the telescope has to be very cold.

“If the telescope were heated by sunlight or the warm glow of the earth, the infrared light emitted by the telescope would outshine its targets, and it wouldn’t be able to see anything.”

The ‘Sunshield’ is made from a polymer-based polyimide film, DuPont Kapton E. Each ot its membranes is as thick as a human hair.

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