What's the best way to take a sample from a violently speeding comet? One that's doing
cartwheels through the cosmos, spewing out chunks of rock and speeding through the solar system at 150,000 miles an hour?
Landing on its surface sounds like risky business, so engineers at NASA's Goddard Space
Flight Center are working on a harpoon gun that can spear the heart of the comet, collect a
sample of subsurface dirt in its tip and reel it back into the hovering craft.
Advertisement - story continues below