An infrared space telescope designed to detect some of the faintest objects in space, the Wide-Field Infrared Survey Explorer, or WISE, discovered 21 comets and more than 33,500 asteroids during its nine-month primary mission alone, snapping more than 1.8 million images.

The spacecraft reached the end of its onboard supply of frozen coolant in October 2010, but continued to survey the sky for asteroids and comets as part of its "warm mission" until February 2012.