Tianwen-2
China's mission to sample a tiny companion of Earth that may be a piece of the Moon.
Key facts
- Agency
- China National Space Administration
- Type of mission
- Asteroid sample return, then comet visit
- Target
- Asteroid 469219 Kamoʻoalewa, then comet 311P/PANSTARRS
- Launched
- 29 May 2025
- Status
- At Kamoʻoalewa
Kamoʻoalewa is a small asteroid, between about 40 and 100 metres across, that follows an orbit around the Sun so similar to Earth's that it seems to circle us slowly. Bodies like this are called quasi-satellites. It spins once every 28 minutes or so.
Its reflected light is reddish and looks like space-weathered lunar rock rather than a typical asteroid. One idea is that it is a fragment thrown off the Moon by an impact, perhaps the one that made the young crater Giordano Bruno on the far side. If that is right, it would be like a lunar meteorite still in space.
The plan
Tianwen-2 launched on a Long March 3B rocket on 29 May 2025 and reached Kamoʻoalewa in mid-2026. It is mapping the asteroid with cameras, a laser rangefinder and radar to choose sampling sites. It is designed to collect material in more than one way: by touching the surface briefly while hovering, and by anchoring itself to the ground. It is planned to leave in 2027 and drop its sample capsule at Earth in late 2027.
The main spacecraft will then use Earth's gravity to head for 311P/PANSTARRS, a main-belt comet: an object in the asteroid belt that sometimes grows dusty tails. It is due there in the mid-2030s.
Why it matters to meteorites
If the samples match Moon rock, they would prove that impacts send lunar fragments into orbits near Earth. Main-belt comets blur the line between asteroids and comets, the two sources of meteorites and meteor showers.
Key dates
| Date | What happened |
|---|---|
| 29 May 2025 | Tianwen-2 launched from Xichang on a Long March 3B rocket. |
| June 2026 | Arrived at the asteroid Kamoʻoalewa. |
| 2027 | Planned departure from Kamoʻoalewa and return of the sample capsule to Earth. |
| 2035 | Planned arrival at the main-belt comet 311P/PANSTARRS. |
See where this mission fits among all the others in the mission timeline.
Did you know?
Kamoʻoalewa is a Hawaiian name, roughly meaning an oscillating celestial fragment.
It is one of the smallest bodies a spacecraft has ever tried to sample.