Crashing a spacecraft into an asteroid may have changed its shape in addition to its trajectory, NASA scientists find

Using a rocket to divert an asteroid may seem like something from a child's story, but NASA achieved exactly that with the DART mission. Launched in September 2022, DART, or the Double Asteroid Redirection Test, was a groundbreaking experiment. It intentionally collided a spacecraft with the small asteroid Dimorphos, not to obliterate it, but to subtly alter its trajectory, showcasing our capability to avert potentially hazardous asteroids in the future.

Recent research suggests that DART may have done more than just redirect Dimorphos; it might have significantly reshaped the asteroid's form. This revelation not only provides clues about Dimorphos' origin but also implies that the upcoming mission to study it will encounter a transformed asteroid rather than an impact crater.

DART's endeavor left scientists uncertain about its long-term consequences and its implications for understanding Dimorphos. Planetary scientist Sabina Raducan and her team chose to simulate the effects of DART's impact rather than directly observing Dimorphos. They recreated Dimorphos and the DART impact, analyzing various outcomes like momentum transfer, ejected material, and Dimorphos' composition and density.

Asteroids vary in composition; some are dense remnants of planetary formation, while others are loosely assembled conglomerates of dust and rock. Both Didymos and Dimorphos fall into the latter category of "rubble piles." Surprisingly, simulations indicate that DART's impact did not create a crater but instead caused a widespread alteration of Dimorphos' surface, suggesting it is exceedingly weak and more akin to a "rubble pile" than previously believed.

Its strength is estimated to be minimal, comparable to asteroids Ryugu and Bennu, which have been studied by spacecraft. Additionally, simulations suggest that Dimorphos has a low density, denser than Ryugu and Bennu but still significantly less dense than Earth. This aligns with the hypothesis that Dimorphos formed from debris shed by Didymos due to its rotational motion.

The European Space Agency's forthcoming Hera mission will play a critical role in validating these findings. If Hera's observations coincide with the simulations, it will offer valuable insights into Dimorphos' evolution, asteroid formation, binary systems, and future deflection techniques.

This research not only sheds light on Dimorphos but also underscores the potential for similar asteroids to undergo substantial changes. Overall, it furnishes essential knowledge for future asteroid exploration and deflection endeavors, highlighting the unpredictability of space exploration, even when meticulously planned.