NASA says NASA asteroids that remain undiscovered pose a key planetary-defense risk, especially mid-sized near-Earth objects around 140 meters or larger. Officials warn these objects can cause serious regional damage if one strikes near a populated area and the biggest concern is what has not been found and tracked yet.
The agency estimates there are about 25,000 mid-sized near-Earth asteroids in this category, with roughly 40% identified so far. That leaves around 15,000 still undetected. Some NASA asteroids are difficult to spot with ground-based telescopes because their orbits can place them close to the Sun’s glare from Earth’s vantage point.
NASA also highlights a readiness gap. There is no operational, ready-to-launch interceptor spacecraft available to deflect a “city killer” asteroid on short notice, even though the 2022 DART mission proved deflection can work by changing an asteroid’s trajectory through impact.
What NASA Says Must Improve Next
- Faster discovery to reduce blind spots
- Space-based infrared detection to find darker objects
- Long-lead planning since a deflection mission can take 8 to 15 years
