On 26 September 2022 humans made our first measurable change to a Solar System object, as NASA’s DART spacecraft impacted the Dimorphos asteroid, shifting its orbit around its larger Didymos parent asteroid.
This grand experiment was a success, but many unknowns remain, to be investigated by ESA’s Hera mission in close-up. What is the precise mass and structure of Dimorphos? Why was it deflected so much more than previous simulations forecast? How did the impact change the Great-Pyramid-sized asteroid? Has it been left with a giant crater, sent spinning wildly or perhaps reshaped entirely?
Finding out will help make the ‘kinetic impactor’ method of planetary defence into a well-understood technique that could be deployed reliably if we ever need it for real.
Launch: 7 October 2024
Target: Asteroid Dimorphos
Rendezvous: November 2026
151 m
target asteroid
1 st
binary asteroid survey
12
mission payloads
2
CubeSats
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Hera spies a half-hidden asteroid moonlet
Another early preview of the Didymos binary asteroid system from ESA’s Hera mission for planetary defence. Acquired from 56 km away, this image shows one face of the main 780-m-diameter Didymos asteroid. A small part of its 151-m-diameter Dimorphos moonlet is also visible, peeking out from near the top of Didymos.
Hera spacecraft in ‘rectangular orbit’ around target asteroids
The European Space Agency’s Hera mission for planetary defence has arrived at its target asteroids. Positioned just 30-25 km away from the binary Didymos system, the small-car-sized spacecraft has commenced its ‘early characterisation phase’ to gather key data on the asteroid pair.