The European Space Agency's Hera spacecraft has resolved the Didymos binary asteroid pair as two separate objects in its own imagery, ESA said in an Oct. 27 release. The monochromatic Asteroid Framing Camera captured the asteroids from 1,280 km away while they were about 197 million km from Earth, according to the agency.

ESA concept art of the Hera spacecraft near the Didymos binary asteroid system.
ESA concept art of the Hera spacecraft near the Didymos binary asteroid system. ESA – Science Office · CC BY-SA 3.0 IGO

ESA said the image was taken on Oct. 18. Before that acquisition, the spacecraft still saw the Didymos system as a single dot, ESA Hera project scientist Michael Kueppers said; Dimorphos is about one pixel in the frame but clearly separated from its parent body.

A pair of thruster firings a week apart had slowed Hera to about 20 m/s relative to the asteroids, ESA reported. Dimorphos is about 151 m across and Didymos about 780 m; they orbit an average 1.15 km apart, with the moonlet moving at about 18 cm/s, according to the agency.