Hitting an asteroid with a katana

In a paper detailing early experiments, the team – including Genrokuro Matsunaga, a 70-year-old swordsmith and Takeo Watanabe at Kanagawa Institute of Technology – explain how they have made several rock corers with various metallic compositions. Four contain tamahagane, the traditional metal made from iron sand and charcoal that is used in Japanese swords. “To achieve the sharpness and plasticity demand of the corer tip, we borrowed the techniques of traditional Japanese sword-smithing in fabricating the corer samples,” the authors write.

The resulting corers are small, cylindrical devices with a bladed edge angled inwards. Instead of swiping a katana sword at the asteroid – which would be cool but impractical – the idea is to launch the tamahagane-tipped corer at the space rock at great speed. In theory, it will dig into the asteroid and allow for a sample to be scooped up. A tether back to the mothership spacecraft could then reel the device and asteroid fragments in.

Yeah, you lost me at "swiping at a katana sword at the asteroid". Everything from this point on is redundant and only for interest's sake.

But even getting surface or near-surface samples is difficult because of a basic property of asteroids: they’re small and don’t have much of a gravitational pull. Every time a rover or collecting device connects with or pushes down against an asteroid, it can easily bounce back off it again. “Anything that allows you to use less force to cut into the asteroid surface – like this tamahagane steel – has to help,” says Elvis.

So far, the Japanese team have tested some of their corers by dropping them down a long pipe towards a concrete slab at the bottom of a tall stairwell. The samplers successfully extracted some concrete, but occasionally dropped it when being retrieved. “A mechanism to prevent samples from falling off during the extraction and recovery phase needs to be devised,” the authors note.

Plus, the tamahagane corers themselves were not tested – because they were so expensive. Still, these are the first steps towards blasting a sword-inspired sampling technology into space.
http://www.bbc.com/future/story/20181113-a-samurai-swordsmith-is-designing-a-space-probe