Bad news from NASA's planetary defense mission: Rocks hurled into space!

The Double Asteroid Redirection Test (DART), announced by NASA in late 2022, made history as a potential defense method against celestial bodies that could threaten Earth. A small spacecraft struck Dimorphos, a moon of the asteroid Didymos, at a speed of approximately 22,500 kilometers per hour, knocking it out of its orbit. This was a first for humanity.

But in the intervening three years, new data on the impact's effects have revealed unexpected results.

PARTS SENT INTO SPACE, A NEW DYNAMIC

According to research published last week in the Planetary Science Journal, a team of astronomers led by the University of Maryland determined that the impact not only deflected the asteroid but also hurled a large amount of rock into space. Some of these rock fragments were found to have more than three times the energy carried by the impacting spacecraft.

"We were able to knock an asteroid out of its orbit. The direct impact of DART caused this shift, but the ejected rocks also created an additional thrust of almost equal magnitude," said Tony Farnham, lead author of the study and a researcher at the University of Maryland.

This creates new physical dynamics that need to be considered in planetary protection missions, Farnham says.

Thanks to a small spacecraft called LICIACube, developed by the Italian Space Agency and deployed to monitor the post-impact area, scientists were able to track 104 rock fragments ejected from Dimorphos. These fragments ranged in size from 20 centimeters to 3.6 meters. However, the researchers noticed that these rocks were not scattered randomly throughout space.

"We found that the rock fragments were not randomly distributed in space. They were clustered in two distinct clusters, with almost no material in other areas. This suggests that something is at work here that we don't yet understand," Farnham explained.

WHAT HAPPENED BEFORE THE COLLISION?

Researchers believe the solar panels on the DART spacecraft may have struck two large rocks, named Atabaque and Bodhran, just before the collision.

Jessica Sunshine, an astronomy professor at the University of Maryland, noted that DART struck a chaotic area covered with large rocks, causing the ejected material to take on a filamentary and scattered structure.

Thanks to the European Space Agency's Hera mission, scheduled to arrive in 2026, the state of Dimorphos and its surroundings will once again be directly observed. This will provide scientists with much clearer data.

Sunshine emphasizes that such details are vital in planning similar future missions:

"If we need to deflect an asteroid coming towards us by a certain amount, all these fine details become extremely critical. You can think of it like a game of cosmic billiards. If we don't account for all the variables, we might not be able to get the ball in the hole."