Hayabusa2
Pieces of a carbon-rich asteroid that turned out to be the purest primitive rock ever studied.
Key facts
- Agency
- Japan Aerospace Exploration Agency (JAXA)
- Type of mission
- Asteroid sample return
- Target
- Asteroid 162173 Ryugu
- Launched
- 3 December 2014
- Samples returned
- 5.4 g of rock and dust
- Status
- Samples returned 2020; extended mission continuing
Hayabusa2 reached the asteroid Ryugu in June 2018. Ryugu is about 900 metres across and shaped like a spinning top, with a ridge around its equator. It is very dark, reflecting less light than coal, and is covered in boulders.
Firsts at Ryugu
In September 2018 two small hopping rovers, MINERVA-II1, became the first rovers to work on the surface of an asteroid. A German and French lander, MASCOT, followed. In February 2019 the spacecraft touched down for a split second and fired a small bullet to collect samples.
In April 2019 it dropped a copper projectile that struck Ryugu at about 2 kilometres per second, making the first artificial crater on an asteroid. In July 2019 it touched down again close to the crater and collected rock thrown out from below the surface, which had been protected from space weathering.
The samples
The capsule landed in Australia on 6 December 2020 with 5.4 grams of material. Ryugu turned out to be closely related to the CI chondrites, the rarest and most chemically primitive meteorites, whose make-up matches the Sun's. The grains contain clay minerals, carbonates, magnetite and sulphides, all formed when liquid water flowed through the parent body. They also hold amino acids and uracil, one of the bases of RNA.
Because the samples never touched Earth's air or water, they show how much CI meteorites have changed after landing.
What next
The spacecraft flew past the asteroid Torifune in July 2026 and is due to reach the tiny, fast-spinning asteroid 1998 KY26 in 2031.
Key dates
| Date | What happened |
|---|---|
| 3 December 2014 | Hayabusa2 launched on an H-IIA rocket. |
| 27 June 2018 | Arrived at the asteroid Ryugu. |
| 21 September 2018 | Two MINERVA-II1 rovers landed: the first rovers on an asteroid. |
| 22 February 2019 | First touchdown and sample collection. |
| 5 April 2019 | Made the first artificial crater on an asteroid. |
| 11 July 2019 | Second touchdown, collecting material from below the surface. |
| 6 December 2020 | The sample capsule landed at Woomera, Australia. |
| 5 July 2026 | Flew close past the asteroid 98943 Torifune. |
| 2031 | Planned arrival at the asteroid 1998 KY26. |
See where this mission fits among all the others in the mission timeline.
Did you know?
Ryugu's grains are so delicate that some CI chondrite meteorites on Earth have grown new minerals, such as sulphate veins, just from reacting with our air.
The asteroid 1998 KY26 is only about 11 metres across, which would make it the smallest asteroid ever visited.