An infrared space telescope that will map the sky in the finest detail yet has successfully launched from the Vandenberg Air Force Base in California aboard a Delta II rocket. NASA's Wide-field Infrared Survey Explorer (WISE) will probe the coolest stars in the universe and the structure of galaxies at four wavelengths between 3 and 25 µm.

Costing $320m, WISE will circle the Earth's poles at an altitude of 525 km, scanning the entire sky one-and-a-half times in nine months. The mission, which is expected to be 1000 times more sensitive than current infrared space probes, will take over 1.5 million images in total, covering almost 99% of the sky.

As WISE is designed to detect infrared radiation from cool objects, the telescope and detectors will be chilled to 12 K with liquid helium. As well as studying stars that are cooler and dimmer than the Sun, WISE will also measure the diameters of more than 100,000 asteroids.

WISE eyes

"The eyes of WISE are a vast improvement over those of past infrared surveys," says Edward Wright, the principal investigator for the mission at the University of California, Los Angeles. "We will find millions of objects that have never been seen before."

NASA's craft will join two existing infrared missions in space: NASA's Spitzer Space Telescope and the European Space Agency's Herschel telescope. Researchers will now spend the next month calibrating the instrument.