From SPACE.com — Gravity-Powered Asteroid Tractor Proposed to Thwart Impact:
A concept spacecraft could use gravity to tow asteroids away from a collision course with earth. Credit: Dan Durda – FIAAA / B612 Foundation.
An asteroid the size of two football fields could wipe out a large city or set off a series of tsunamis across the world. The threat of such an Earth-smashing asteroid has lead scientists to dream up several methods of defending the planet against such a catastrophe.
Solutions have ranged from pushing the asteroid with a spacecraft to mounting a thruster on its surface. But pushing it would require too much fuel and could break up the asteroid. Also, asteroids rotate, which could complicate the firing of a surface thruster.
Now, two NASA astronauts have presented a plan for an “asteroid tractorâ€â€”an unmanned, 20-ton spacecraft that uses the invisible bond of gravity to gently pull an asteroid into a new, non-threatening orbit.
Related item: check out my Space Rocks animation.
UPDATE: The Space Tractor is featured on today’s Astronomy Picture of the Day.