The European Space Agency's Hera spacecraft has reached a critical milestone on its deep space journey, transmitting a striking black-and-white photograph of the Didymos asteroid system from approximately 37 miles, or 60 kilometers, away. This initial close-up view captures the side of the larger Didymos asteroid that NASA's DART spacecraft never directly observed before smashing into its smaller companion body. Mission researchers expressed immediate astonishment upon receiving the telemetry and images, noting that the newly revealed hemisphere displays surface characteristics vastly different from what scientists previously anticipated.
Patrick Michel, the Hera principal investigator, remarked on the unexpected visual data during a statement released by the mission team, describing the target as looking entirely like a whole new world. The incoming data marks the beginning of an intensive phase for the European mission, which was designed specifically to investigate the aftermath of a human-instigated cosmic collision that took place years prior.
Key takeaways
- The ESA Hera probe photographed Didymos from a distance of about 37 miles away.
- The new image reveals the side of Didymos that NASA's DART spacecraft never observed.
- Scientists identified boulders, craters, and strange grooves that may be fallout from the impact.
- Hera launched on October 7, 2024, to follow up on NASA's September 2022 DART mission.
The aftermath of the historic DART collision
In September 2022, NASA executed a bold planetary defense test by crashing a 1,260-pound, or 570-kilogram, spacecraft straight into Dimorphos. Dimorphos is a 558-foot-wide, or 170-meter-wide, space rock that orbits its larger companion, Didymos, which spans 2,625 feet, or 800 meters, across. Ground-based observations following the high-speed impact confirmed that Dimorphos's orbital period around Didymos successfully shortened from 11 hours and 55 minutes down to 11 hours and 23 minutes. While astronomers and mission planners immediately deemed the test a technical success, scientists recognized that a dedicated rendezvous mission was necessary to fully examine the physical consequences of the kinetic strike.
To answer these lingering questions, the Hera spacecraft launched on October 7, 2024, embarking on a multi-year journey through space. The primary objective of the mission is to gather precise data that will help researchers determine whether DART's kinetic impact strategy can be turned into a dependable, repeatable method for protecting Earth from potential asteroid threats. The newly captured image of Didymos exhibits a familiar central ridge along its equator, but the surrounding terrain deviates sharply from prior observations. The hemisphere features multiple boulders, distinct craters, and unusual patterns of grooves or ridges that immediately drew the attention of mission scientists.
Investigating strange grooves and planning ahead
The science team behind the mission hypothesizes that some of the newly observed surface features on Didymos might be direct fallout resulting from the violent impact. Specifically, researchers suggest that debris could have been violently thrown across the 0.6-mile, or 1-kilometer, gap separating the two space rocks when DART struck Dimorphos. In the newly released frame, the smaller companion moonlet Dimorphos appears only as a tiny sliver visible just below its much larger parent asteroid.
As the Hera spacecraft continues closing in on its final destination, it will prepare to spend at least six months thoroughly surveying the entire Didymos asteroid system. Michael Kueppers, the ESA Hera mission scientist, emphasized the scale of the upcoming work in a public statement, noting that researchers look forward to seeing much more of both bodies and systematically mapping every single structural change identified across the binary system.
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