NASA's Roman Space Telescope to aid asteroid detection alongside dark energy mission

NASA plans to launch the Nancy Grace Roman Space Telescope from Kennedy Space Center in Florida at the end of August 2026. The observatory's primary mission is to study dark matter and dark energy, surveying over a billion galaxies with a 300-megapixel infrared camera that captures a field of view roughly 100 times larger than the Hubble Space Telescope.

A multi-institutional team of planetary scientists and astronomers will present a proposal at the Europlanet Science Congress in The Hague this September outlining how Roman can simultaneously detect asteroids. The telescope's wide field of view and infrared sensitivity allow it to spot asteroids as small as 60 feet long, comparable to the Chelyabinsk meteor that injured 1,500 people in 2013.

Roman's software currently discards streaks caused by moving objects like asteroids to maintain clear cosmological images. Researchers including Bryan Holler at the Space Telescope Science Institute and Andy Rivkin at the Johns Hopkins Applied Physics Laboratory propose analyzing these discarded streaks to identify and track near-Earth objects.

While not designed as a planetary defense observatory, Roman would complement the James Webb Space Telescope (JWST) and the upcoming Near-Earth Object (NEO) Surveyor, set to launch in 2027. JWST can intensely study individual asteroids but has a narrow field of view, while NEO Surveyor is dedicated to finding 90% of city-killer asteroids larger than 460 feet.

Roman's advantage lies in its ability to observe multiple candidate asteroids quickly across a large sky area. If NEO Surveyor identifies several objects with uncertain orbits, Roman could refine their trajectories within days using its wide field and different vantage point in space.

The telescope's infrared observations also provide estimates of an asteroid's size and composition — whether stony, carbon-rich, or metallic — which helps assess potential impact damage or the effort needed for deflection.

NASA's Planetary Defense Coordination Office estimates roughly 25,000 near-Earth asteroids 460 feet or larger exist, with just over half still undiscovered. An additional 230,000 asteroids around 165 feet long orbit near Earth, fewer than 10% of which have been located.

Ground-based telescopes and the Vera Rubin Observatory in Chile, which began a 10-year survey in 2026, will continue to play major roles. Researchers emphasize that Roman will not lead planetary defense but will help prioritize which objects warrant follow-up by oversubscribed facilities like JWST.