NASA’s DART mission to deflect the asteroid moon Dimorphos has provided valuable insights into the effectiveness of kinetic impactors in altering an asteroid’s orbit. However, a new study published in the Planetary Science Journal reveals that the massive barrage of boulders ejected during the impact may complicate future asteroid deflection efforts.
Researchers from the University of Maryland found that the ejection of 104 boulders, ranging from 0.2 to 3.6 meters in radius, carried more than three times the momentum of the DART spacecraft itself. The team tracked the locations and velocities of these rocks using images taken by LICIACube, a small Italian spacecraft.
The study suggests that the ejected boulders were clustered in two distinct groups, with an absence of material elsewhere, indicating that something unknown is at work here. The largest debris cluster was ejected towards the south at high velocities and shallow angles to the surface.
According to Jessica Sunshine, a professor of astronomy and geology at UMD, the study highlights the importance of considering variables such as surface features and target composition when planning asteroid deflection missions. “Comparing this mission with Deep Impact’s results gives us insight into how different types of celestial bodies respond to impacts,” she said.
The findings have implications for future asteroid deflection efforts, including the European Space Agency’s Hera mission, which will arrive at the Didymos-Dimorphos system in 2026. The team’s work on understanding the effect of boulder debris will be crucial to ensuring the success of these missions.
Source: https://phys.org/news/2025-07-massive-boulders-ejected-dart-mission.html