NASA’s Wide-field Infra-red Survey Explorer (WISE), a powerful infra-red space telescope, is running out of coolant, and has warmed up to the point where the longest wavelength detector is no longer functional. The coolant is necessary to keep the detectors at a frigid 260°C below zero – any warmer and their own heat overwhelms the faint infra-red light that WISE is supposed to detect.
WISE was never intended to last long (not more than ten months) and the gradual venting of coolant is by design, so this latest development was not unexpected. The primary phase of the mission (mapping the entire sky in infra-red) was completed on 17 July 2010. The second phase, a repeat of the initial survey in order to spot anything that might have changed or moved, is now under way. WISE has already discovered more than 15 new comets and 29,000 new asteroids (of which a staggering 100 pass near enough to Earth to require careful attention) in it’s first survey, comprised of 1.5 million snapshots combined into a panoramic view of the entire cosmos.
All that remains now is for the mission to continue with the second pass until the remaining coolant is used up, after the which WISE will be put into standby mode and left to circle the Earth in peace until its orbit finally decays some 20 to 30 years from now. A peaceful retirement for a productive satellite!
View the official press release here: http://www.nasa.gov/mission_pages/WISE/news/wise20100810.html