Asteroid Landings Call For Robots With a Soft Touch

How do you land on an asteroid? A lot of very talented engineers have thought about it. Putting a robotic spacecraft down safely on a moon or planet is hard enough, with the pull of gravity to keep you humble. But when it comes to an asteroid, where gravity may be a few millionths of what it is on Earth, is “landing” even the right word?NASA’s OSIRIS-REx mission is due back on Earth on 24 September after a seven-year voyage to sample the regolith of the asteroid 101955 Bennu&md