ESA's Hera spacecraft approaches its target asteroids Dimorphos and Didymos
ESA's Hera spacecraft is due to reach the asteroid pair Dimorphos and Didymos in November 2026, traveling at 12 km/s relative to Earth. Dimorphos, 151 m across, orbits the larger 780-m diameter Didymos at an average distance of 1.15 km. Both asteroids are composed of silicon-rich rock with surfaces comparable in brightness to the lunar highlands. Didymos rotates every 2.2 hours and features relatively smooth dusty plains, while Dimorphos, extensively reshaped by NASA's DART impact on 26 September 2022, is dominated by large boulders ranging from car to house-sized. The gravitational pull on Didymos is about 40,000 times weaker than Earth's, while Dimorphos's gravity is about 200,000 times weaker.
