ESA’s Hera returns first close-up views of Didymos and Dimorphos

The European Space Agency announced on November 5, 2026 that its Hera spacecraft caught its first close-up glimpse of the binary asteroid Didymos and its moonlet Dimorphos, with the spacecraft about 37 miles (60 km) from Didymos when it took the image.

On October 18, Hera’s black-and-white Asteroid Framing Camera imaged Didymos and Dimorphos from about 1,280 kilometers (795 miles), resolving the pair as separate objects rather than a single dot while roughly 197 million kilometers (122 million miles) from Earth. Dimorphos appeared as only around one pixel but was clearly well separated from its parent body. “With this image, the smaller Dimorphos asteroid becomes visible for the first time,” said Hera project scientist Michael Kueppers.

Two thruster firings separated by one week reduced Hera’s speed to only 20 meters per second (45 miles per hour) relative to the asteroid duo, enabling a gradual approach. On October 15, 2026, the spacecraft ignited three hydrazine-based thrusters simultaneously for a 93-minute continuous burn, cutting its speed relative to the asteroid pair by several hundred meters per second. ESA reported the maneuver went well.

Earlier in October the spacecraft captured its initial view of the target from roughly 146,954 miles (236,500 kilometers) away. Come early November, the probe will pass within 20 miles (30 kilometers) of the asteroid pair and start collecting data, before releasing the shoebox-sized cubesats Milani and Juventas during January 2027.

On September 26, 2022, NASA’s DART spacecraft impacted Dimorphos at 6.1 kilometers per second (3.8 miles per second), sending debris across 10,000 kilometers (6,200 miles) of space and slowing the asteroid’s orbit by around 33 minutes. Ground observations showed the moonlet’s orbital period changed to 11 hours and 23 minutes from 11 hours and 55 minutes after the collision.

Dimorphos measures about 151 meters (495 feet) across while Didymos is approximately 780 meters (2,560 feet) in diameter, according to some measurements; ESA also gives Didymos at roughly 800 meters and Dimorphos at about 560 feet (170 meters). The two asteroids orbit an average of 1.15 kilometers (0.71 miles) apart, with Dimorphos moving around its parent at about 18 centimeters per second (7.1 inches per second).

Key unknowns include whether DART left a crater or reshaped Dimorphos entirely, the asteroid’s precise makeup, structure and mass, and which properties explain a deflection far greater than impact simulations predicted. Ground-based observations carry an estimated 10 percent residual uncertainty, and impact models have not yet been able to calculate Dimorphos’s mass and makeup.

Hera will gauge the asteroid’s mass and altered orbit with greater accuracy and carry out a detailed survey of a binary asteroid category that represents roughly 15 percent of known asteroids and has never previously been examined close up. Over the coming months Hera will conduct a close-up crash site investigation of Dimorphos using multiple instruments and a pair of shoebox-sized CubeSats, eventually progressing to landing.

Milani will measure the sunlight reflected by the surfaces and separate it into colors to learn how the asteroids have interacted with space, while also sampling nearby dust to look for water, identify light organics, and watch for molecular contamination. Juventas will carry out the first-ever radar probe of an asteroid’s inside, peering about 328 feet (100 meters) into the 525-foot (160-meter) moonlet, followed by radio-science tests, a low-frequency radar survey, and an X-ray-like scan, then a landing and several days of surface work.

The mission marks the first-ever study of a binary asteroid system, centering on Dimorphos as an impact crime scene while also surveying Didymos and the dust cloud produced by the collision. ESA identified three mysteries Hera will help solve: whether Dimorphos is a rubble pile or a solid core covered in boulders, mapping the DART crater to 4-inch (10-centimeter) resolution or finding the whole asteroid was reshaped, and determining whether the pair share the same material to test the idea that rapidly spinning Didymos shed debris that formed Dimorphos.

About 15 percent of known asteroids are binary systems, but their origins remain mysterious, and Hera’s density and composition measurements will address the rubble-pile question and the shared-material hypothesis. Following its two-year trip through space, the spacecraft should devote at least six months to studying the Didymos asteroid pair, examining what the DART impact did and collecting data to advance planetary defense.

Hera launched on October 7, 2024 aboard a SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station at 10:52 a.m. ET. The Falcon 9 first-stage booster B1061 flew its 23rd and final mission without recovery because the interplanetary transfer orbit required additional performance.

ESA announced that detailed images of both asteroids will be released on November 25. ESA mission manager Ian Carnelli said the imagery will become much sharper as the spacecraft approaches, and that the first detailed images of Dimorphos—the first solar system object whose orbit was measurably shifted by human action—will be shown on November 25.

Patrick Michel, Hera principal investigator, described the new view as looking at a whole new world: “The first thing we said was wow! This is the other side of Didymos from the one that DART’s camera showed us shortly before impact.” The imagery shows the side of Didymos opposite the face seen by DART’s camera before impact, featuring the same central equatorial ridge but otherwise appearing different with multiple boulders, craters, and possible groove or ridge patterns.

ESA Hera mission scientist Michael Kueppers said impact-ejected material may have crossed the approximately 1 km from Dimorphos to Didymos, and some observed characteristics could originate from that transport. The team plans systematic mapping of changes ahead and expects to see much more of both bodies.

Hera’s investigation will refine knowledge of the DART impact and help keep Earth safe from future asteroid collisions. The collision nudged Dimorphos slightly out of its former orbit, and material thrown off by the impact could have produced a new meteor shower at Earth.