Posted on behalf of Adam Mann

Old satellites never die; they just get decommissioned. At least that was the fate of NASA’s Wide-field Infrared Survey Explorer (WISE), when project officials turned off the telescope’s transmitter on 17 February. WISE had already completed its principal mission of recording the entire night sky in infrared wavelengths back in October and, after an extended mission to catalogue near-Earth asteroids, was placed in hibernation mode at the beginning of February.

“We’re not thrilled and we even held a little wake yesterday,” says Peter Eisenhardt, project scientist for the mission. “But we said we’d turn it off and that’s what we did.”

The satellite was launched in December 2009 for a ten-month mission and spent its time scanning the sky for galaxies, stars, asteroids, and comets. After finishing 1.5 sky scans, WISE ran out of coolant. NASA officials approved it to go on at warmer temperatures where just two infrared wavelengths worked, forcing it to only see close-by objects. At this temperature, it spotted 9 previously unseen comets and more than 33,500 asteroids.

The satellite is still operational and could be used again, but a compelling science case has not been presented to NASA to collect new data, says Eisenhardt. Since most of the infrared spectrum cannot penetrate Earth’s atmosphere, humanity’s window on the infrared universe is reduced to two portals. The Spitzer Space Telescope, also without coolant, can still observer at the same near infrared wavelengths as WISE did during its extended phase (3.4 and 4.6 microns), while the Herschel Space Observatory is sensitive to far infrared wavelengths beyond 60 microns. Both missions are expected to end next year. Researchers will then have to wait for the launch of the James Webb Space Telescope, currently slipping behind schedule to 2015 or beyond, to observe in the infrared.

Though NASA has no specific plans for a follow-up to WISE, there are some proposals to fly a large, more-dedicated mission, says Eisenhardt. Such a telescope could help in NASA’s Congressional mandate to identify 90% of asteroids that could cause significant damage to the Earth, he adds.

In April, the infrared astronomy community will get a taste of the WISE information when the mission releases the first 57% of its data. The blogosphere has recently been abuzz over the idea that this data might contain a clue to a previously unknown giant planet in the distant outer solar system, nicknamed Tyche. WISE’s full dataset will be available in 2012.