By Paul Rincon
Science editor, BBC News website
Publishedduration20 minutes agoshareSharenocloseShare pagelinkCopy linkAbout sharingimage copyrightDLR
A Japanese spacecraft is about to deliver to Earth the first large sample of rock and soil from an asteroid.
The Hayabusa-2 probe will release its precious sample cache, which is expected to parachute down to a safe landing in the Australian outback.
It grabbed the cosmic treasure trove last year from Ryugu, an asteroid regarded as a particularly primitive relic from the early Solar System.
Studying the rocks could provide insights into how life itself began.
The operation should begin at about 05:30 GMT on Saturday, when the capsule containing asteroid samples will separate from the main spacecraft.
While the capsule heads home to Earth, the "mothership" will change its orbit to bypass our planet.
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Later, on Saturday evening, the capsule should be visible to skywatchers in Australia's Coober Pedy region as a fireball streaking overhead.