Japanese scientists preparing to blast a crater in an asteroid to find out what it is made of said they have successfully tested their new space cannon.
The Japan Aerospace Exploration Agency (Jaxa) said the huge weapon would fire a metal bullet at the surface of asteroid 1999JU3 some time in 2018.
The Hayabusa-2, which will launch the weapon, will then land on the surface and take samples of the newly disturbed soil in a search for organic materials or for any sign of water.
The craft is set to be carried into space next year by one of Jaxa's H2A rockets, which are launched from southern Japan.
The probe will be flung on a trajectory that its operators hope will take it into the path of 1999JU3 four years later.
The asteroid is thought to be more likely than many others to harbour the building blocks of life.
Once it has reached its destination, Hayabusa-2 will hover above the asteroid to release the space cannon, which is intended to drift gently towards the barren surface.
As the weapon floats down, Hayabusa-2 will make its way around to the other side of the asteroid, where it can shelter its delicate sensor array from any flying debris or shrapnel.
With its mother ship safely out of the way, the cannon will detonate itself, hurling a large, bullet-like object into the surface below it. After the dust has settled, Hayabusa-2 will return to inspect the crater, touching down on the asteroid's surface, where it will scoop up samples for analysis back on earth.
The probe is expected to find its way home some time in 2020, carrying with it a valuable scientific load that is expected to be seized on by scientists.