Researchers at NASA start developing comet harpoon

The researchers want to send a spacecraft to rendezvous with a comet and then fire a harpoon to rapidly acquire samples from specific locations with ‘surgical precision’ while hovering above the target.

A metal ballista (large crossbow) measuring almost 6ft (1.8m) in height, with a bow made from a pair of truck leaf springs and another bow string made of steel cable, has been set up in a lab to give the researchers an idea of how the comet harpoon would work in reality.

The ballista is set up in the lab to fire vertically downwards into a bucket of target material. For safety, it is pointed at the floor, because it could potentially launch test harpoon tips about a mile if it was angled upwards.

An electric winch mechanically pulls the bow string back to generate a precise level of force, up to 1,000lb (450kg), firing projectiles to velocities upwards of 100ft/sec.