Hera
Europe's detective mission to study the asteroid moon that DART struck.
Key facts
- Agency
- European Space Agency (ESA)
- Type of mission
- Asteroid orbiter with two cubesats
- Target
- Asteroid 65803 Didymos and its moon Dimorphos
- Launched
- 7 October 2024
- Status
- Arriving at Didymos in late 2026
DART showed that an asteroid can be nudged, but telescopes on Earth could not see exactly what the impact did. Hera is designed to find out. It will measure the mass of Dimorphos, the size and shape of the crater or scar left by DART, and the make-up of both asteroids. With those numbers, scientists can work out how efficient the push really was and turn a single experiment into a technique that could be repeated if it were ever needed.
The journey
Hera launched on a Falcon 9 rocket on 7 October 2024. On 12 March 2025 it flew past Mars for a gravity assist and photographed the small Martian moon Deimos from about 1,000 kilometres. In early 2026 a series of engine burns set it on course to reach Didymos late in 2026.
Three spacecraft
Once there, Hera will release two shoebox-sized cubesats. Milani will map the minerals on the surface and study dust. Juventas carries a radar that will look inside Dimorphos, the first radar sounding of an asteroid's interior, before attempting to land. Hera itself has cameras, a laser rangefinder and an infrared imager that measures how quickly the surface heats and cools, which reveals whether it is solid rock or loose gravel.
Why it matters to meteorites
Didymos is linked by its colours to the ordinary chondrites. Hera's measurements of density and porosity will show how such asteroids are put together, and the mission will compare its data with ordinary chondrites studied in laboratories.
Key dates
| Date | What happened |
|---|---|
| 7 October 2024 | Hera launched on a Falcon 9 rocket. |
| 12 March 2025 | Flew past Mars and photographed its moon Deimos. |
| March 2026 | Completed the deep-space engine burns that aim it at Didymos. |
| November 2026 | Due to reach the Didymos system. |
See where this mission fits among all the others in the mission timeline.
Did you know?
Hera is named after the Greek queen of the gods.
Its Juventas cubesat will try to measure the gravity of an asteroid less than 200 metres across while sitting on its surface.