The Double Asteroid Redirection Test (DART) mission has successfully demonstrated the feasibility of deflecting asteroids using a kinetic impactor. By intentionally crashing a spacecraft into an asteroid, scientists tested whether the impact could alter its path. The target was Dimorphos, a small companion orbiting a larger asteroid called Didymos.
The DART spacecraft struck Dimorphos at over 22,500 kilometers per hour, successfully shortening its roughly 12-hour orbit by about 33 minutes. However, the change in momentum didn’t come solely from the spacecraft itself. The plume of debris ejected from the impact site added to the total push on the asteroid.
A small companion spacecraft called LICIACube flew past moments after the collision and snapped images of the debris cloud. Through reanalysis of these images, researchers were able to track 104 boulders in the ejected material. These boulders ranged in size from 0.2 meters to 3.6 meters in radius and carried significant momentum.
The authors found that the boulders were clustered, suggesting they were ejected in preferred directions. This non-uniform distribution likely changed Dimorphos’ orbital plane. The momentum imparted by boulder ejection also altered the asteroid’s rotational state.
Researchers believe that the ejected rocks may be the shattered remains of two large boulders on the surface of Dimorphos. These boulders were likely struck by solar panels during the DART spacecraft’s approach. The shallow angles and high ejection speeds support this scenario.
The European Space Agency’s Hera mission, en route to arrive in 2026, aims to carry out an in-depth post-impact analysis. This will help determine if Dimorphos is tumbling in its modified orbit and assess the momentum transfer from the impact debris. The data collected during DART will refine asteroid deflection strategies for future missions.
The study’s findings have significant implications for planetary defense, as they demonstrate that kinetic impactors can be a viable method for deflecting potentially hazardous objects.
Source: https://astrobites.org/2025/08/20/shot-by-the-dart-and-were-to-blame-now-that-space-rock-wont-be-the-same