spacetoday.net: WMAP mission ends; WISE enters extended mission

Posted: Sun, Oct 10, 2010, 3:33 PM ET (1933 GMT)
WISE spacecraft illustration (NASA)

One NASA astronomy mission came to a formal end last week while another entered a new phase. NASA announced last week that the Wilkinson Microwave Anisotropy Probe (WMAP) spacecraft, launched in 2001, fired its thrusters for the last time last month to move into a parking orbit around the Sun. WMAP had been operating at the Earth-Sun L2 point, 1.5 million kilometers farther from the Sun than the Earth, studying the cosmic microwave background radiation. Those observations allowed astronomers to refine the age of the universe and measure the relative abundances of dark energy, dark matter, and ordinary matter in the universe. Meanwhile, NASA also announced that the Wide-field Infrared Survey Explorer (WISE) spacecraft has entered a new phase of observations after expending all of its coolant. WISE was launched in December 2009 with a supply of frozen hydrogen designed to cool its infrared detectors. That hydrogen has been used up, so astronomers are now looking for asteroids and comets with infrared detectors on the spacecraft that don't require the coolant to operate. This extended mission is slated to last one to four months.