NEOWISE
An infrared telescope that measured the sizes of tens of thousands of asteroids.
Key facts
- Agency
- NASA (United States)
- Type of mission
- Infrared space telescope
- Target
- The whole sky; asteroids and comets
- Launched
- 14 December 2009 (as WISE)
- Status
- Ended 2024
WISE, the Wide-field Infrared Survey Explorer, was launched in December 2009 to map the whole sky in infrared light, the heat glow given off by warm objects. Asteroids are dark and often hard to see in visible light, but the Sun warms them, so they glow brightly in the infrared.
Measuring asteroids
An asteroid's brightness in visible light depends both on its size and on how dark its surface is, so a small shiny asteroid can look like a large dark one. Its infrared glow depends mainly on its size. By combining the two, WISE could measure both the size and the darkness, called albedo, of each asteroid it saw.
After its coolant ran out in 2010, the telescope continued as NEOWISE, searching for near-Earth objects. It was put to sleep in 2011 and woken in 2013 for a dedicated asteroid hunt that lasted until 2024. Over its life it observed more than 40,000 asteroids and comets in the main belt and found hundreds of new near-Earth objects. It also discovered comet C/2020 F3 NEOWISE, the bright comet that was seen with the naked eye in July 2020.
Why it matters to meteorites
Albedos help sort asteroids into types: bright ones such as Vesta's family, dark ones linked to carbonaceous chondrites. NEOWISE's census showed how the dark, carbon-rich asteroids are spread through the belt. Its orbit decayed and it burned up in the atmosphere in November 2024.
Key dates
| Date | What happened |
|---|---|
| 14 December 2009 | WISE launched on a Delta II rocket. |
| February 2011 | Put into hibernation after its first survey. |
| December 2013 | Restarted as NEOWISE to search for near-Earth objects. |
| 27 March 2020 | Discovered comet C/2020 F3 NEOWISE. |
| 8 August 2024 | The survey ended. |
| 1 November 2024 | Re-entered Earth's atmosphere and burned up. |
See where this mission fits among all the others in the mission timeline.
Did you know?
Comet NEOWISE will not return to the inner Solar System for about 6,800 years.
Infrared light is what night-vision cameras use to see warm objects in the dark.
Related pages
Comets connected with this mission: Comet NEOWISE. See all comets.