The European Space Agency’s planetary‑defence spacecraft Hera has produced its first image that distinguishes the two asteroids of the Didymos system. Captured on the evening of 18 October from a distance of roughly 1,280 km, the monochromatic Asteroid Framing Camera resolved the primary body Didymos and its smaller companion Dimorphos as separate points of light, confirming the binary nature of the system that lies about 197 million km from Earth.
First separate view of the binary pair
Mission scientist Michael Kueppers explained that prior to this acquisition the spacecraft saw the system as a single dot. In the new image, Dimorphos appears as a faint feature roughly one pixel wide, yet it is clearly isolated from its parent body. “With this image the smaller Dimorphos asteroid becomes visible for the first time,” Kueppers said. “Before this acquisition the spacecraft was still resolving the Didymos system as a single dot. But now, even though Dimorphos is made up of only around one pixel in this initial image, it is clearly well separated from its parent body.”
Mission manager Ian Carnelli added that the view marks a milestone for a mission built specifically to study a double‑asteroid system. “For the very first time we are seeing through Hera’s own eyes the very double asteroid system that the mission was designed and built for,” he noted, and indicated that image clarity will improve as the spacecraft continues its approach, with a detailed view of Dimorphos expected on 25 November.
Background: DART impact and mission objectives
The significance of Hera’s observations is tied to the 26 September 2022 kinetic‑impact experiment conducted by NASA’s DART spacecraft. DART struck Dimorphos at 6.1 km/s, generating a debris plume that stretched across 10,000 km of space and slowing the moonlet’s orbital period by roughly 33 minutes. The impact demonstrated that a human‑made collision could measurably shift an asteroid’s trajectory, a first for planetary‑defence techniques.
Despite the successful deflection, scientists still lack precise knowledge of how the impact altered Dimorphos itself. Key questions remain about whether a crater formed, how the asteroid’s shape may have changed, and what the exact composition, internal structure and mass of Dimorphos are—factors that could explain why the observed orbital change exceeded predictions from impact simulations.
Future investigations and mission timeline
In the weeks ahead, Hera will conduct a close‑up “crash site investigation” of Dimorphos. The spacecraft carries multiple scientific instruments and will deploy two shoebox‑sized CubeSats to obtain even nearer observations before attempting a landing. The mission’s fine‑tuned navigation follows a pair of thruster firings performed earlier in October, which reduced Hera’s relative speed to about 20 m/s with respect to the asteroid pair. This slowdown enables a gradual, controlled descent toward the targets.
Dimorphos measures approximately 151 m across—comparable in size to the Great Pyramid of Giza—while Didymos spans about 780 m, a little shorter than the Burj Khalifa skyscraper. The two bodies orbit each other at an average separation of 1.15 km, with Dimorphos moving around its parent at roughly 18 cm/s. These dimensions and orbital parameters provide a natural laboratory for testing kinetic‑impact deflection models.
Public engagement is also part of Hera’s plan. The mission has introduced the Hera Space Companion, an AI‑driven chatbot that offers real‑time answers about the spacecraft’s journey and findings, aiming to make ESA’s inaugural planetary‑defence mission accessible to a broad audience.
Helene Elliott is the Lead Science & Space Reporter at News Raise. She reports on aerospace missions, astrophysics discoveries, quantum research, and environmental technology.
