Engineers on NASA’s Near-Earth Object Wide-field Infrared Survey Explorer mission commanded the spacecraft to turn its transmitter off for the last time at the end of July. Thus ending the space telescope’s search for asteroids and comets, including those that could pose a threat to Earth.

NASA ended the mission because NEOWISE will soon drop too low in its orbit around Earth to provide usable science data. An uptick in solar activity is heating the upper atmosphere, causing it to expand and create drag on the spacecraft, which does not have a propulsion system to keep it in orbit.

During its operational lifetime, the infrared survey telescope exceeded scientific objectives for not one but two missions, starting with the Wide-field Infrared Survey Explorer mission.

Managed by JPL, WISE launched in December 2009 with a seven-month mission to scan the entire infrared sky. By July 2010, WISE had accomplished this with far greater sensitivity than previous surveys. A few months later, the telescope ran out of the coolant that kept heat produced by the spacecraft from interfering with its infrared observations.

NASA extended the mission under the name NEOWISE until February 2011 to complete a survey of the main belt asteroids, at which point the spacecraft was put into hibernation. Analysis of this data showed that although the lack of coolant meant the space telescope could no longer observe the faintest infrared objects in the universe, it could still make precise observations of asteroids and comets that generate a strong infrared signal from being heated by the Sun as they travel past our planet.

The space agency brought the telescope out of hibernation in 2013 under the Near-Earth Object Observations Program, a precursor for the agency’s Planetary Defense Coordination Office, to continue the NEOWISE survey of asteroids and comets in the pursuit of planetary defense.

By repeatedly observing the sky from low Earth orbit, NEOWISE created all-sky maps featuring 1.45 million infrared measurements of more than 44,000 solar system objects. Of the 3,000-plus near-Earth objects it detected, 215 were first spotted by NEOWISE. The mission also discovered 25 new comets, including the famed comet C/2020 F3 NEOWISE that streaked across the night sky in the summer of 2020.

Now decommissioned, NEOWISE is expected to safely burn up in our planet’s atmosphere in late 2024.