In order to protect the Earth, some sacrifices must be made. NASA’s DART spacecraft is currently on its way to a binary asteroid system known as Didymos and will essentially crash into one tiny asteroid to test out a deflection method. But rather than leaving behind an impact crater as initially intended, the DART spacecraft may actually deform the mini-moon, making it nearly unrecognizable.
Using a new model, a group of researchers have simulated the entire cratering process and discovered that the asteroid deflection mission might completely alter its target, changing its appearance far more severely than previously believed.
“The DART impact could globally deform Dimorphos, and therefore change its overall shape significantly, instead of creating just a small crater,” Martin Jutzi, co-author of the study, which was published in The Planetary Science Journal, told Gizmodo in an email.
As seen in the above illustration, the mini-moon, dubbed Dimorphos (formerly known as Didymoon), could take on one of these six possible shapes following the spacecraft’s impact. The whole cratering process could take a few hours, which is why previous models of the impact did not predict the asteroid’s subsequent deformation. “Previous models were only able to simulate the first seconds of such events,” Jutzi said.
Short for Double Asteroid Redirection Test, the DART mission launched in November 2021 towards the Didymos asteroid system. Didymos is an 800-metre wide rock with its own 170-metre wide moon known as Dimorphos, the main target of DART. The spacecraft will smash into the mini-moon at 24,140 km per hour (24, 140 kilometers per hour), attempting to offset its orbit. The impact is scheduled for late September or early October, when the pair will come within 7 million miles (11 million kilometers) of Earth.
The purpose of the test is to experiment with kinetic impactor technology as a means of deflecting asteroids that could be headed towards Earth. NASA and other space agencies, keep a close watch on asteroids that come too close for comfort in order to assess whether or not they pose a threat to our planet. But as far as defending Earth from incoming asteroid impacts, there’s no clear cut plan on what to do.
“These weak asteroids could actually be deflected much more strongly and larger amounts of material could be ejected from the impact than the previous estimates predicted,” Jutzi said. “These larger effects should be easier to observe immediately after the DART impact.” So the DART mission will still be able to perform the experiment, just perhaps with a different outcome than initially anticipated.
The European Space Agency (ESA) is also planning a follow-up mission to the pair of space rocks. ESA is scheduled to launch its Hera mission in 2024, which will rendezvous with Didymos by 2026 to study the impact crater left behind by DART, and any other changes made to the asteroid. If Dimorphos has indeed taken on a different appearance, it may provide valuable data on the asteroid itself.
“Ideally, this will allow us to learn something about the asteroid’s interior, rather than just the surface,” Jutzi said. “This would in turn provide very valuable information about the asteroid’s bulk properties and improve our understanding of asteroids in general.”