NASA Begins All-Sky Infrared Survey
NASA successfully launched Dec. 14 its WISE (Wide-field Infrared Survey
Explorer) mission with a pre-dawn, picture-perfect takeoff from Vandenberg Air
Force Base in California. WISE is
an unmanned satellite carrying an infrared-sensitive telescope that will image
the entire sky in infrared light.
Just 10 seconds after the spacecraft separated from a Delta II rocket, NASA acquired a signal from WISE. Approximately 3 minutes later, WISE reoriented itself with its solar panels facing the sun to generate its own power. The rocket deposited WISE into a polar orbit 326 miles above Earth.
"All systems are looking good, and we are on our way to seeing the entire infrared sky better than ever before," said William Irace, the mission's project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
The next major event in the launch happened just minutes later when the valves on the cryostat, a chamber of super-cold hydrogen ice that cools the WISE instrument, opened. Because the instrument sees the infrared, it must be kept at chilly temperatures. Its coldest detectors are less than minus 447 degrees Fahrenheit.
"WISE needs to be colder than the objects it's observing," Ned Wright of UCLA, the mission's principal investigator, said in a statement. "Now we're ready to see the infrared glow from hundreds of thousands of asteroids, and hundreds of millions of stars and galaxies."
The space telescope will spend nine months scanning the sky once, then one-half the sky a second time. The primary mission will end when WISE's frozen hydrogen runs out, about 10 months after launch. NASA's last infrared survey of the sky was performed 26 years ago.
Powered by solar panels and orbiting several hundred miles above the dividing line between night and day on Earth, the telescope will look out at right angles to the sun and will always point away from Earth. As WISE orbits from the North Pole to the equator to the South Pole and then back up to the North Pole, the telescope will sweep out a circle in the sky. As Earth moves around the sun, this circle will move around the sky, and after six months WISE will have observed the whole sky.