A European probe now circles an asteroid that NASA deliberately struck in 2022, positioning itself for the closest look yet at a cosmic crash site. The encounter marks a pivotal moment for planetary defense research.
The European Space Agency confirmed Wednesday that its Hera spacecraft has moved within 15 to 18 miles of Didymos and its smaller companion, Dimorphos. That distance translates to 25 to 30 kilometers, giving instruments an unprecedented vantage point.
Hera’s mission centers on the aftermath of NASA’s Double Asteroid Redirection Test, known as DART. That earlier spacecraft slammed into Dimorphos to test whether a kinetic impact could shift a hazardous asteroid off course. The collision shortened the moonlet’s orbit around Didymos and altered its trajectory around the sun.
Next month, the car-sized Hera will creep even nearer. Officials plan to bring the spacecraft just 12 miles, roughly 20 kilometers, from the battered surface. ESA leaders frame the operation as a crash site investigation, complete with 25 science instruments plus two shoebox-sized CubeSats designed to survey Dimorphos and potentially touch down on it.
The original impact threw boulders and rubble thousands of miles into space. Some debris may still linger near the asteroid pair, according to scientists. Unraveling what remains could reveal how much force actually transferred to Dimorphos and how such impacts behave in deep space.
Dimorphos measures an estimated 500 feet, or 151 meters, across. Didymos spans roughly 2,560 feet, equivalent to 780 meters. Data gathered in the coming weeks will help researchers understand whether a future spacecraft could deflect a dangerous asteroid bound for Earth.
Meanwhile, Hera’s close flybys will map surface features, measure crater dimensions, and analyze the structure of both bodies. Those readings should determine whether DART simply carved out a crater or reshaped Dimorphos entirely. As a result, planetary protection teams may soon know how to design effective deflection missions for real threats.
