Astroid Patrol? Defenders of the Spaceways? This isn't Science Fiction

"Asteroid Gravity Tractor Idea: Funded Study"
LiveScience (June 20th, 2008)

"There’s been lots of powerpoint talk and back of the envelop calculation regarding use of a 'gravity tractor' to deflect an asteroid that might endanger Earth.

"The physics behind the idea is that a spacecraft would position itself near a menacing asteroid and ever-so-slightly pull it off course thanks to the gravitational attraction between the two bodies.

"But now a detailed study of the gravity tractor is underway, making use of an expert team at Jet Propulsion Laboratory and CalTech. That's the word from former Apollo astronaut, Rusty Schweickart - now Chairman of the Board and Founder of the B612 Foundation which is dedicated to detecting, tracking and deflecting near Earth objects (NEOs)...."

This idea isn't as crazy it my sound. The physics of using one mass to move another are quite straightforward - Newton worked out the basics quite a while ago.

And, sooner or later, something big is going to fall on Earth. I visited a mile-wide hole in the ground in the American Southwest where that happened, not all that long ago.

So, I'm glad to see that serious attention is being paid to methods of nudging rocks and iceballs out of the way.