NASA thought it had found the solution to protect the land from threats from space. But a new element changes the situation. A recent study shows that diverting an asteroid is much more complex than expected.
For several years, scientists closely have been monitoring objects that have bordered on the earth. Certain asteroids, such as 2024 YR4 recently photographed by the James Webb telescope, worry by their unpredictable trajectory. Although in offerings, the latter recalled the importance of developing reliable methods to avoid a catastrophic impact. Faced with this potential threat, several space agencies work on techniques to change the trajectory of dangerous asteroids.
Among these initiatives, NASA tested the Dart mission in 2022, which aimed to strike the asteroid Dimorphos to divert the trajectory. The idea was simple: use a direct impact to reduce the risk of future collision with our planet. This test showed that the latter’s orbit around his companion Didymos had been shortened by 32 minutes. However, new analyzes published in July 2025 in The Planetary Science Journal bring an unexpected surprise. These results indicate that the deviation method is more difficult to master than expected.
NASA strikes the dimorphos asteroid and discovers that giant blocks complicate the deviation
At the time of the impact, Dart hit two large rocky blocks, called Atabaque and Bodhran, located on the surface of Dimorphos. The images of the Little Italian Satellite Licicube, launched as an accompaniment, revealed that Dozens of rocks, some reaching more than 7 meters, were projected at high speed. These blocks have dispersed in two very distinct clusters, then confirmed by the Hubble telescope. This massive ejection gave a surplus of asteroid impulse by modifying its trajectory more strongly than provided by the simple collision of the probe. The researchers also noticed that the majority of blocks came from only one of these large rocks.
The researchers calculated that these blocks have brought three times more force than the probe itself. This now requires reviewing the simulation models to prepare a possible planetary defense. Unlike the Tempel 1 asteroid hit by the Deep Impact mission in 2005, Dimorphos has a very irregular surface, full of rocks. These differences show that each asteroid reacts unique to an impact. To confirm these results, the HERA mission of ESA will go there in 2026 to study the remaining debris. These data are crucial, because poorly anticipating the reaction of an asteroid could make an ineffective rescue mission.
