A space capsule that's been collecting dust and rock from the surface of an asteroid is set to return to Earth.
The Japanese sent the Hayabusa probe into space seven years ago.
No-one yet knows whether it managed to grab samples from the surface of the asteroid Itokawa.
If it has managed to collect dust then it will be the first time ever.
Scientists are hoping it will give us clues about how the Earth was formed.
The Hayabusa probe will release a capsule into the atmosphere on the way back to Earth - the spacecraft will be destroyed but the capsule should survive re-entry into the atmospere and land in Australia.
A clever tracking system has been attached to the container which will help guide scientists to the drop location.
The Japanese have had massive problem with the probe - so if the capsule manages to collect even dusty fragments, they will be overjoyed!
It could be months before scientists are able to say whether Hayabusa did capture fragments of Itokawa.
Even tiny particles would provide new look into the early history of the Solar System and the formation of the planets more than 4.5 billion years ago.