NASA Sky-mapping Telescope Starts New Mission … Without Coolant

This story was updated at 12:10 p.m. ET.

A prolific NASA space telescope that is mapping the entire sky has run out of vital coolant needed to keep its detectors from warming up, but that hasn't stopped its mission to seek out hidden asteroids, comets and other objects.

NASA's Wide-field Infrared Survey Explorer, or WISE, is turning its camera eye on asteroids and comets within our solar system as part of its new NEOWISE Post-Cryogenic Mission. It allows the space telescope to continue scanning the cosmos despite the lack of frozen hydrogen onboard to keep its infrared detectors as cold as designed.

"Two of our four infrared detectors still work even at warmer temperatures, so we can use those bands to continue our hunt for asteroids and comets," said Amy Mainzer of NASA's Jet Propulsion Laboratory in Pasadena, Calif., in a statement. Mainzer is leading the WISE telescope's new mission. [Gallery: WISE Telescope Photos]

NASA telescope's new mission

The new NEOWISE mission, which takes its name from the near-Earth objects the telescope will hunt, is expected to last at least one month, and possibly as long as four months, NASA officials said.

To date, the WISE telescope has discovered 19 comets and more than 33,500 asteroids, including 120 near-Earth objects, which are objects with orbits that pass relatively close to Earth's own orbit around the sun. The space observatory has taken about 1.8 million images of the sky using its main 16-inch (40-cm) telescope and four infrared detectors.

NASA launched the WISE telescope in December 2009 on a 10-month mission to completely map the entire sky. So far, it has mapped the sky 1 1/2 times.

In addition to asteroids and comets, the telescope observed odd cold stars called brown dwarfs, as well as hidden galaxies that are dark in visible light but shine bright in the infrared range of the light spectrum.

"WISE has provided a guidebook to the universe with thousands of targets worth viewing with a large telescope," said WISE principal investigator Edward Wright of the University of California, Los Angeles. "We're working on figuring out just how far away the brown dwarfs are, and how luminous the galaxies are."

WISE telescope win

The longer mission is a big win for WISE telescope scientists.

In May, a NASA advisory panel recommended against extending the space telescope's mission once its supply of hydrogen coolant ran dry.

At the time, NASA's 2010 Astrophysics Senior Review Committee said there was not adequate scientific justification to continue the mission. That proposed three-month extension would have added $6.5 million to the telescope's $320 million mission price tag.

NASA spokesperson J.D. Harrington told SPACE.com that after the WISE telescope's coolant ran out late last week, the space agency's planetary division decided to fund an extended mission to continue the search for near-Earth asteroids. The mission extension will cost about $400,000 for one month.

"At the end of that month, the collected data will be analyzed and a decision made as to whether it justifies extending the mission another three months," Harrington said in an e-mail. "The possible four-month extension is what it would take to complete one full scan of the solar system."

The NEOWISE mission is expected seek out more than nearby asteroids and comets. The extended mission should also allow the telescope to study the closest brown dwarfs to the sun, as well as revisit previous targets to see how they've moved since they were first spotted.

The science results from the first half of the WISE telescope's sky survey will be released in spring 2011, NASA officials said.

"The science data collected by WISE will be used by the scientific community for decades," said Jaya Bajpayee, NASA's WISE program executive at the agency's headquarters in Washington. "It will also provide a sky map for future observatories like NASA's James Webb Space Telescope."

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