A Follow-Up to a Cosmic Collision

Years after NASA's DART (Double Asteroid Redirection Test) mission intentionally crashed into the asteroid Dimorphos to test planetary defense strategies, a new explorer is nearing the scene of the impact. The European Space Agency (ESA) spacecraft, Hera, is scheduled to arrive this month to conduct an in-depth examination of the collision site.

The original mission, which occurred in September 2022, successfully altered the orbit of the small asteroid Dimorphos around its larger companion, Didymos, by approximately 33 minutes. While ground-based and space telescopes have provided preliminary data, scientists are eager to obtain a closer look at the actual damage inflicted.


The Detective Mission

"Hera wants to be the detective, like Inspector Colombo, going back to the crash scene," explained Patrick Michel, principal investigator of the Hera mission and a planetary scientist at the French National Centre for Scientific Research (CNRS). The goal is to move beyond the "basic sketch" currently held by researchers and understand the true geological impact of the crash.

Despite the success of the DART experiment, many questions remain:

  • What is the exact size and shape of the crater formed by the impact?
  • Did the collision cause significant structural rearrangement of the asteroid's surface boulders?
  • What caused the unexpected, ongoing changes in the asteroid's orbit months after the initial impact?

Arriving and Observing

Hera’s arrival maneuvers begin on October 15. Through a series of carefully calibrated braking actions, the probe will slow down to approach the binary system. By early December, the spacecraft is expected to be in position for close-up observations. Scientists are particularly interested in seeing how the celestial body has changed.

"For us, it's like a new world," Michel noted regarding the anticipation of receiving new imagery. "The new image won't have anything to do with the previous one, so that's really exciting."


Advanced Probes and Future Insights

As the mission progresses into 2025, Hera will deploy two secondary cube-satellites:

«Milani will identify the composition of materials on and around Dimorphos. The other, Juventas, will use radar to peer inside Dimorphos — the first time scientists have ever been able to study the interior of a space rock directly.»

The mission is scheduled to operate through at least September 2027, providing humanity with its first detailed, up-close study of a binary asteroid system. This data will be vital for refining future planetary defense strategies, ensuring that should a real threat appear in the future, the world is better prepared to protect the planet.