NASA’s infrared space telescope NEOWISE has discovered hundreds of asteroids and comets, mapping the solar system and protecting Earth from potential impacts since its launch in 2009. But after over a decade of service, the pioneering spacecraft is now facing its final days as increased solar activity from our Sun threatens to overwhelm its systems.
Successful asteroid hunting mission faces hazardous environment
The NEOWISE space telescope, originally known as WISE, was launched as a space-based infrared mapper to survey the entire night sky. In 2017, NASA revived the spacecraft to devote it to locating potentially hazardous near-Earth asteroids and comets. Targeting these near-Earth objects (NEOs) has been an extremely successful endeavor for NEOWISE over the last 5 years, as the table below shows:
| Year | NEOs Discovered | Comets Discovered |
|---|---|---|
| 2017 | >190 | 29 |
| 2018 | 216 | 21 |
| 2019 | 120 | 12 |
| 2020 | 155 | 18 |
| 2021 | 261 | 32 |
| 2022 | 248 | 26 |
However, the increasing activity of the Sun as part of its natural 11-year cycle has begun creating an extremely hazardous environment for the probe. Power levels onboard NEOWISE have declined as its orbit draws it closer to the Sun. Higher temperatures and intense ultraviolet radiation will soon overwhelm NEOWISE’s cooling systems leading to failure of key components.
“Passing inside of the distance of Mercury from the Sun has heated up the spacecraft to the point where we can no longer cool our longest-wavelength channel,” said Amy Mainzer, NEOWISE principal investigator at NASA’s Jet Propulsion Laboratory. “This effectively ends the prime mission.”
Efforts to prolong service reach their limit
NASA attempted to prolong NEOWISE’s service life by prioritizing observation of the most critical near-Earth asteroids, comets and cosmically close stellar systems. But the extreme environment has now exceeded NEOWISE’s engineering limits.
Experts say the loss of NEOWISE will leave a gap in monitoring potentially dangerous asteroids, especially those coming from the direction of the Sun where ground-based telescopes have difficulty spotting them against the glare.
“NEOWISE produced the lion’s share of new asteroid discoveries while in orbit,” said Mike Kelley, an astronomer at the University of Maryland. “Now astronomers will have to work harder to undertake the asteroid reconnaissance needed to address the impact hazard.”
However, astronomers continue to develop new infrared detection technologies and NASA plans future successor missions to track Earth-approaching objects. The Nancy Grace Roman Space Telescope set to launch in 2027 will detect asteroids using similar infrared sensors.
An unprecedented view of our solar system thanks to pioneering mission
While the imminent loss of the NEOWISE mission is lamentable, astronomers widely celebrate its transformative contributions to planetary science over the past decade.
Among its prolific mapping of our solar system and discoveries of asteroids and comets, highlights of NEOWISE’s mission include:
- Mapping the entire infrared sky 1.5 times from 2009-2011 discovering vast new features even in familiar celestial objects
- Discovering 29 new comets in 2017 including the closest comet to pass the Sun ever observed
- Revealing key new insights into asteroid and comet sizes, numbers, and orbits providing clues into solar system evolution
- Undertaking the most comprehensive infrared survey to date of the asteroid belt between Mars and Jupiter
- Capturing unique data to help identify dead comets and transitioning asteroids
- Demonstrating new uses of spacecraft still able to produce impactful science long past their prime missions
- Contributing to major scientific advances thanks to open public release of all NEOWISE data
Astronomers will continue analyzing this wealth of NEOWISE observations for years even after the mission concludes.
“NEOWISE delivered more than only stability of funding over a decade,” noted Mainzer. “It advanced our knowledge of solar system bodies within an entirely new portion of the light spectrum.”
An irreplaceable view of potentially hazardous asteroids
With NEOWISE’s loss, experts caution about a worrisome possibility. An asteroid could be careening toward Earth but escape detection since ground-based telescopes might be unable to spot it against the Sun’s glare, especially smaller city-killer sized asteroids.
In 2013, the Chelyabinsk meteor that exploded over Russia, injuring 1500 people, arrived undetected from the Sun-ward direction. The over 20-meter wide rock penetrated our atmosphere faster than the speed of sound, creating a shock wave that blew out windows and collapsed roofs. Today it still remains unclear if telescopes could have provided sufficient warning to mitigate casualties and damage from that impact.
Prior to entering hibernation in 2011, NEOWISE demonstrated unique success detecting asteroids difficult for ground-based systems to spot including smaller ones down to roughly 50 meters wide. Experts have lauded this as an extremely useful capability providing greater response time to identify worrisome threats emerging from the daytime sky.
While the Nancy Grace Roman Telescope will continue NEOWISE’s legacy hunting for these elusive solar system bodies, its 2027 launch leaves a multi-year observation gap. With NEOWISE concluding operations, some experts worry if we might miss spotting another dangerous asteroid like the Chelyabinsk meteor in time to prevent injuries or damage.
Hope still remains detecting potentially hazardous objects
Yet despite the loss of NEOWISE’s unique threat detection capabilities, astronomers emphasize there remains much hope protecting Earth from asteroid and comet impacts thanks to major investments over the past decades.
A host of sky surveys continue operation including Pan-STARRS in Hawaii able to spot faint asteroids down to ~100 meters wide plus the upcoming Vera Rubin Observatory that could detect even smaller 30-meter objects. Experts remain confident these systems provide sufficient warning to identify imminent impact threats emerging from nighttime skies.
Additionally, steady progress continues developing new space-based observatories equipped with advanced infrared sensors designed to pick up asteroids NEOWISE tracked best. Not only will the Nancy Grace Roman Telescope continue this effort but also missions under formulation like the Near-Earth Object Surveillance Mission (NEOSM) propose demonstrating concepts for a dedicated asteroid tracking satellite network.
Furthermore, scientists better understand asteroid orbits and behavior enabling reliable calculation of impact risk decades in advance. Radar dishes support tracking orbits of newly discovered objects while missions like DART demonstrate the promising possibilities of one day deflecting an asteroid found on impact trajectory.
“Losing NEOWISE undoubtedly stings given all its contributions safeguarding Earth these past five years,” said Kelley. “But it thankfully exits the scene at a time when steady progress develops successors ensuring Earth remains vigilant tracking hazardous objects.”
So while astronomers regret NEOWISE’s imminent loss, its pioneering legacy securing our planet continues thanks to the flourishing asteroid detection capabilities it championed over its storied mission blazing new trails in space-based planetary defense.
To err is human, but AI does it too. Whilst factual data is used in the production of these articles, the content is written entirely by AI. Double check any facts you intend to rely on with another source.
