A Japanese asteroid probe is expected to bring back a capsule that is believed to contain rock samples in about a year's time.
Hayabusa2 started its full-fledged return journey on Tuesday.
The probe spent a year and a half exploring the Ryugu asteroid. During that period, it successfully landed on the asteroid and collected rock samples from below its surface.
Scientists hope the samples will provide clues about the origins of life and how the solar system was formed.
Hayabusa2 is now about 250 million kilometers from the Earth.
It is scheduled to release the re-entry capsule in November or December next year.
Japan's space agency will collect the capsule and distribute the rock samples to six research teams. They hope to start analyzing the samples in mid-2021.