Washington: NASA has developed a space harpoon to take samples from comets with surgical precision without landing on the rugged celestial bodies.
Engineers at the US space agency`s Goddard Space Flight Center in Greenbelt, Maryland, have built a trial harpoon that is six feet tall.
The bow is made out of a pair of springs normally used to provide the suspension for trucks. The bow string is made out of steel cable half an inch thick.
It can fire projectiles at speeds of more than 100ft per second. Test projectiles are fired into large drums filled with sand, rock salt, ice or pebbles.
"We had to bolt it to the floor, because the recoil made the whole testbed jump after every shot," the BBC quoted the project`s lead engineer, Donald Wegel as saying.
The engineers believe it would be safer to collect comet material using the equipment rather than trying to land on the celestial bodies.
NASA said the space harpoon could be projected "with surgical precision" from a spacecraft hovering above the target.
Experts said this would avoid the risk of trying to anchor the craft to a comet`s rugged surface.
Comets are much smaller than planets and have much lower gravity as a consequence, so a landed spacecraft would have to find some way of attaching itself to the object to avoid floating off.
NASA said that the samples from comets could reveal the origins of the planets and how life was created on Earth.
Comets are made up of frozen chunks of ice, gas and dust. They orbit the sun and, if they are close enough to the star, project a tail in the opposite direction made up of ionized gases.