A diligent surveyor of the night skies, NEOWISE is sadly approaching its fiery demise as the Sun’s erratic outbursts are causing the infrared telescope to gradually fall out of its orbit before it eventually burns up in Earth’s atmosphere.
NASA’s NEOWISE, or Near-Earth Object Wide-field Infrared Survey Explorer, will be rendered unusable in early 2025 due to increased solar activity, the space agency announced. The telescope’s orbit is expected to gradually lower over time. This is due to the heating of Earth’s atmosphere by the Sun, which causes the atmosphere to expand. As a result, satellites in orbit—including NEOWISE—experience increased atmospheric drag, leading to a decrease in their altitude.
The Sun is approaching its solar maximum, a period with cranked-up solar flares and explosive coronal mass ejections. During this period of the Sun’s 11-year cycle, atmospheric gases will slow down NEOWISE, pulling it lower in Earth’s atmosphere. As a result, the telescope will not be able to maintain its orbit around our planet.
“After several years of calm, the Sun is waking back up,” Joseph Masiero, deputy principal investigator of the NEOWISE mission, said in a statement. “We are at the mercy of solar activity, and with no means to keep us in orbit, NEOWISE is now slowly spiraling back to Earth.”
NEOWISE had so far avoided the Sun’s wrath over the past 10 years of its reactivated mission. The space telescope launched in 2009 with a goal of conducting a survey of the sky in infrared light, capturing distant galaxies, cool stars, and exploding white dwarf stars with far more sensitivity than other surveys. At the time, it was just known as WISE (Wide-field Infrared Survey Explorer). The telescope mapped the sky twice before it ran out of cryogenic coolant, which helped it observe infrared wavelengths without the heat from the spacecraft itself interfering with its observations. Afterwards, WISE was placed in hibernation in February 2011.
After nearly three years of floating around with no purpose, the telescope was given a second life. NASA repurposed the mission in December 2013 to survey near-Earth objects, helping guard our planet against potential threats. Over the past 10 years in service, NEOWISE scanned the entire sky over 20 times and made 1.45 million infrared measurements of over 44,000 solar system objects, according to NASA. The telescope observed more than 3,000 near-Earth objects, 215 of which it had discovered, including a long-period comet by the same name.
“NEOWISE has showcased the importance of having an infrared space survey telescope as part of NASA’s planetary defense strategy while also keeping tabs on other objects in the solar system and beyond,” Amy Mainzer, the mission’s principal investigator at the University of Arizona in Tucson, said in a statement.
Even after it is gone, researchers will still rely on the valuable data gathered by NEOWISE to continue to make new discoveries. “This is a bittersweet moment. It’s sad to see this trailblazing mission come to an end, but we know there’s more treasure hiding in the survey data,” Masiero said. “NEOWISE has a vast archive, covering a very long period of time, that will inevitably advance the science of the infrared universe long after the spacecraft is gone.”