NASA's infrared sky-mapping telescope has snapped its first image of the cosmos three weeks after launch, confirming the spacecraft's sensitive detectors are ready to create an atlas of the universe.

This image of a region in the constellation Carina was taken shortly after the WISE satellite ejected its dust cover. Credit: NASA/JPL-Caltech/UCLA

"I think the most important event in the life of a telescope is the first light," said William Irace, the Wide-field Infrared Survey Explorer project manager at the Jet Propulsion Laboratory.

WISE launched from a California military base Dec. 14 and jettisoned the telescope's dust cover two weeks later.

The image released by NASA on Wednesday shows a region in the constellation Carina containing about 3,000 stars, including a relatively bright swelling red giant star, according to David Leisawitz, WISE mission scientist at the Goddard Space Flight Center.

WISE glimpsed cool interstellar dust glowing in infared light on the left side of the picture, proving the $320 million mission can accomplish what it set out to do -- map the infrared universe and detect countless new galaxies, stars and asteroids.

"Our sky is filled with such stuff, and WISE will see that in plentiful amounts," Leisawitz said.

The first light image was taken in an 8.8-second exposure, part of an engineering test to verify the 16-inch telescope and four detectors work properly.

"We are definitely in focus," Irace said.

WISE will repeat the process 7,500 times each day during its primary mission.

"This is a snapshot of the sky taken with WISE," Leisawitz said. "Over the course of its mission, it will take literally millions of these snapshots to complete a survey of the entire sky. Each one of those little snapshots is about three times the size, in area, of the moon."

The satellite will take pictures every 11 seconds, scanning the entire sky at least one-and-a-half times by October, when the craft's reservoir of super-cold solid hydrogen is expected to run out.

WISE needs the hydrogen to cool its detectors enough to permit the telescope to see some of the coldest objects in the universe.

The survey phase of the mission will begin in a couple of weeks. Officials are now working to match the motions of the spacecraft and the scan mirror to create "freeze-frame" images.

"WISE is now poised to deliver on its promise to measure hundreds of millions of stars, hundreds of millions of galaxies, and hundreds of thousands of solar system objects, such as asteroids," Leisawitz said.

The mission's final results won't be available to the public until March 2012, but scientists will unveil selected images beginning next month.