ESA's Hera Reaches the DART Crash Site: First Close-Up of Didymos Reveals the Side No Camera Ever Saw

DARMSTADT, Germany — ESA's Hera spacecraft has arrived at the Didymos binary asteroid system and sent back its first close-range image of the world humanity deliberately changed, the agency announced on Thursday, 5 November 2026. Taken from about 60 kilometres away by Hera's Asteroid Framing Camera, it shows the face of the 780-metre-wide Didymos that no camera had ever seen — a rugged, boulder-strewn hemisphere — with its moon Dimorphos, struck by NASA's DART in 2022, visible at lower left, partly in shadow.

Illustration: ESA's Hera spacecraft approaches the binary asteroids Didymos and Dimorphos. This is an artist's impression, not a photograph of the actual spacecraft or asteroids.

What Happened

On Thursday, 5 November 2026, ESA announced that Hera had reached its destination — the Didymos asteroid system, 196.8 million kilometres from Earth — and released its first close-range science image — the first view of this side of Didymos.

Until now, every close view of Didymos came from DART, which photographed only one hemisphere during its final approach in September 2022. The new image shows the opposite face. Both hemispheres share one familiar feature — the raised ridge girdling Didymos's equator — but otherwise the new side looks strikingly different.

"The first thing we said was wow!" said Hera principal investigator Patrick Michel of CNRS/Observatoire de la Côte d'Azur. "This is the other side of Didymos from the one that DART's camera showed us shortly before impact, so this feels like looking at a whole new world. This side of Didymos has the same central ridge along its equator that we saw before, but otherwise appears very different, with multiple boulders and craters and what look like patterns of grooves or ridges."

That difference is the mission's first puzzle. The new hemisphere is crowded with boulders at a density the team had not anticipated, scored with grooves and ridges unlike the terrain DART documented. Some features may be ancient, shaped by Didymos's history as a fast-spinning "top-shaped" asteroid; others may be brand new — debris thrown off Dimorphos by the DART impact, which rained down on its larger companion.

"Since we expect a lot of impact-ejected material to have made it across the approximately 1 km of space from Dimorphos to Didymos, it may be that some of these characteristics originate from this transport of material," said Hera mission scientist Michael Kueppers. "We have exciting work ahead of us to sort it out. We look forward to seeing much more of both bodies and systematically mapping all the changes we identify."

The image also shows how far Hera has come in weeks. On 18 October, from 1,280 kilometres away, the same camera first resolved Didymos and Dimorphos as two separate objects — Dimorphos was barely a single pixel. Since then Hera has closed the distance more than twenty-fold, braking with thruster burns to match the asteroids' speed. Radio signals take roughly 11 minutes to travel one way between Earth and the spacecraft.

Background

To understand why one photograph of a grey rock matters, rewind to 26 September 2022, when NASA's Double Asteroid Redirection Test — DART — ended its mission exactly as planned: by driving itself into Dimorphos, the 151-metre-wide moonlet orbiting Didymos, at roughly 6.6 kilometres per second (about 14,750 miles per hour). It was the first deliberate test of a kinetic impactor — using a spacecraft's momentum to nudge an asteroid off a collision course with Earth.

The test worked better than expected. DART's impact shortened Dimorphos's orbital period around Didymos by approximately 33 minutes — far more than the 73-second change that would have counted as mission success. The collision threw up a debris plume some 10,000 kilometres long, and reshaped the little moonlet. But DART's camera was destroyed in the impact. It returned images of Dimorphos's boulder-covered surface down to a few centimetres per pixel in its final minutes, then went silent — leaving a crater of uncertain size and depth, a reshaped surface, an altered orbit, and a debris cloud whose fate was unknown.

That is the gap Hera was built to close. It launched on 7 October 2024 aboard a SpaceX Falcon 9 from Cape Canaveral, Florida, beginning a two-year cruise that included a gravity-assist swing past Mars in March 2025. The €363 million mission carries twelve scientific instruments, plus two shoebox-sized CubeSats, Milani and Juventas, that will fly closer to the asteroids than the main spacecraft can safely go. Hera is operated from ESA's European Space Operations Centre in Darmstadt, Germany.

Hera spent most of October 2026 shedding speed to match the Didymos system's orbit. On 15 October it fired its Orbit Control Thrusters for 93 minutes continuously — a braking manoeuvre ESA called the most challenging operational activity since launch — cutting its velocity relative to the asteroids by a few hundred metres per second. A second, shorter burn fine-tuned the trajectory a week later. Only then could the science begin: first the 18 October image that separated the two asteroids, and now the first close-range view of Didymos itself.

The boulders match observations made after the impact. The Hubble Space Telescope confirmed that at least 37 boulders, 1 to 6.7 metres across, were ejected from Dimorphos. A 2025 study on arXiv (preprint 2503.08158) found most such boulders would eventually re-impact Dimorphos or Didymos, gouging craters an estimated 0.2 to 2.9 metres across. The boulder field Hera is now photographing on Didymos may be, in part, Dimorphos's own debris, flung across the roughly one kilometre between the two bodies.

Illustration: A close-up view of the boulder-strewn surface of asteroid Didymos, with craters, grooves and a raised equatorial ridge. This is an artist's impression, not the actual photograph.

Why It Matters

At its core, the mission is about turning a one-off stunt into a reliable engineering technique — the difference between knowing an asteroid can be deflected once and knowing how to do it again, on purpose, against a real threat.

The key number is the momentum enhancement factor, known as beta. A spacecraft striking an asteroid delivers its own momentum (beta of 1), but an impact also blasts surface material off in the opposite direction, and that ejecta carries momentum of its own, amplifying the deflection. A 2023 study in Nature put DART's beta at 3.61: the total momentum transferred to Dimorphos was roughly 3.61 times the momentum DART carried, with ejected debris contributing about 2.6 times as much as the impactor alone.

That is favourable for planetary defence: a relatively small spacecraft, striking at the right angle, can deflect a much larger asteroid than its mass alone would suggest. But the number is uncertain — depending on what Dimorphos actually weighs, the true beta could lie anywhere from 2.2 to 4.9. Dimorphos's mass has never been directly measured, and ground-based estimates carry wide error bars, because mass requires knowing both volume and density, and density is almost impossible to infer reliably from Earth.

Hera will measure Dimorphos's mass directly, by tracking its own trajectory through the system's gravity field. Combined with a laser-altimeter survey of the DART crater's depth and volume, that will collapse the beta range to a precise value — converting the DART experiment from "a deflection that worked once" into "a technique that can be engineered to work again," the foundation for any future mission that must move a genuinely dangerous asteroid.

Hera is also the first detailed survey of a binary asteroid — about 15 percent of known asteroids are binaries — and comparing the two bodies will test whether the fast-spinning Didymos once shed the debris that formed its moon.

Illustration: NASA's DART spacecraft strikes Dimorphos in 2022, throwing up a plume of rocky debris, with Didymos nearby. This is an artist's impression, not a photograph of the event.

What Happens Next

Hera has entered its early characterisation phase, observing both asteroids from roughly 25 to 30 kilometres while refining shape models and mapping the global distribution of boulders.

Next, on 25 November 2026, ESA will release the first detailed, full-resolution images of both asteroids — including the DART impact site on Dimorphos, seen in detail for the first time since 2022.

Over the following months, Hera will move progressively closer: to about 10 kilometres in December, then 4 kilometres, and eventually about 1 kilometre from Dimorphos. Early in 2027 it will deploy its two CubeSats — Milani, for close-up spectral observations of the impact site, and Juventas, carrying the first ground-penetrating radar ever flown to an asteroid, designed to probe up to 100 metres below Dimorphos's surface. Both CubeSats are planned to end their missions by touching down on Dimorphos.

During the close observation phase, the laser altimeter will measure the depth and volume of DART's crater, while radio tracking of Hera's motion through the system's gravity pins down the masses of both asteroids. ESA plans for the mission at Didymos to run at least through June 2027, with a possible extension, ending with a final descent toward Didymos.

For now, the mission has delivered what its team waited two years to see: a new world, close up — and a mystery, written in boulders.

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FAQ

What did ESA's Hera spacecraft photograph on 5 November 2026?

Hera's first close-range science image of the Didymos system, from about 60 kilometres away. It shows the face of the 780-metre-wide Didymos that DART's camera never saw — a rugged hemisphere of boulders, craters, grooves and ridges — with the 151-metre moonlet Dimorphos at lower left, partly in shadow.

How is this image different from Hera's earlier pictures of Didymos?

It is far closer and far more detailed. On 18 October 2026, from about 1,280 kilometres away, Hera first resolved Didymos and Dimorphos as two separate objects, with Dimorphos barely a single pixel. The 5 November image was taken from roughly 60 kilometres — more than twenty times closer — and shows individual surface features across a hemisphere of Didymos that DART never photographed. The 15 October braking manoeuvre produced no science image.

Why does Didymos's newly imaged side look different from the side DART saw?

Scientists are not yet certain. The new hemisphere shares the equatorial ridge seen on the DART side, but is more densely covered in boulders and marked by grooves and ridges. One hypothesis is that some boulders are debris ejected from Dimorphos by the 2022 impact, which crossed the one kilometre between the two bodies and settled on Didymos; a 2025 study predicted most ejected boulders would re-impact one of the two asteroids.

What is Hera trying to measure at Dimorphos?

Hera aims to complete the planetary defence experiment DART began: measuring Dimorphos's mass directly, mapping the DART crater, and determining the composition and internal structure of both asteroids. Together, those measurements will pin down the momentum enhancement factor — the extra deflection the ejected debris provided — turning a one-off demonstration into a technique engineers can rely on.

When will we see detailed images of Dimorphos and the DART impact site?

ESA will release the first full-resolution images of both asteroids on 25 November 2026. Hera will then move closer — to 10 kilometres, then 4, and eventually about 1 kilometre — and deploy its Milani and Juventas CubeSats early in 2027. The mission is planned to run at Didymos at least through June 2027.

Sources

• EarthSky — "Hera mission gets its 1st closeup view of Didymos and Dimorphos" (5 November 2026)
• Tech Times — "ESA Hera Reaches Asteroid Didymos: First Close Image Shows Side DART Never Photographed" (5 November 2026)
• ESA — "Destination sighted: Hera's first glimpse of Didymos" (esa.int)
• ESA — "N° 57–2024: Planetary defence mission Hera heading for deflected asteroid" (7 October 2024)
• ESA — "Finding Hera's way: Flight Dynamics team in action" (7 October 2026)
• ESA NEO Coordination Centre — Newsletter September 2026
• SpaceNews — "ESA continues Hera launch preparations amid Falcon 9 grounding" (October 2024)
• SpacePolicyOnline — "Against the Odds, Hera Lifts Off on Its Planetary Defense Mission" (7 October 2024)