NASA shuts down down asteroid-hunting NEOWISE telescope as the sun drags it to its doom

NASA's only space telescope dedicated to planetary defense has turned off its transmitter for the last time, ending its 15-year career detecting near-Earth asteroids and comets.

The spacecraft — named NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer) — vastly outlived its original seven-month mission to scan the sky for infrared signals. It ultimately detected more than 200 previously unknown near-Earth objects, including 25 new comets, and provided a wealth of data on 44,000 other objects that zoom through our solar system, according to NASA.

NEOWISE's mission, which officially ended on July 31, is finally coming to an end as the sun's era of peak activity, called solar maximum, threatens to drag the satellite into Earth's atmosphere for a final, fiery reentry. The spacecraft, which lacks propellant to thrust itself into a higher orbit, has been steadily falling toward Earth for years and is expected to safely burn up in the atmosphere in late 2024.

"This telescope has really outlived its original [lifespan]," Amy Mainzer, a professor at the University of California, Los Angeles and principal investigator for both NEOWISE and its planned successor, NEO Surveyor, told Live Science in an interview last year. "We got so much more out of it than we were expecting to get."

Related: 'Planet killer' asteroids are hiding in the sun's glare. Can we stop them in time?

Retirement and rebirth

NEOWISE launched in 2009 as simply WISE, the Wide-field Infrared Survey Explorer. Like a prototypical version of the James Webb Space Telescope, WISE entered orbit with a mission to map the entire sky in infrared light, looking for traces of faint and ancient emissions from the early universe.

Its original seven-month mission showed that WISE was far more sensitive than scientists had expected. NASA then extended the mission under the name NEOWISE to last until 2011, so the telescope could survey the main asteroid belt between Mars and Jupiter. The telescope was then put into hibernation after running out of coolant, which kept the spacecraft's heat from leaching into NEOWISE's infrared sensors and reducing their sensitivity.