[Vince Ferrer]

I'd like to develop space factories which land on asteroids and process them into something useful. With a long enough lead time, why just move things around?

[Coyoteman]

A tractor spacecraft would be a good idea.

You would need space docking and refueling. What would the propulsion system be? It would need to catch asteroids early enough that small changes in their orbits would translate to clean misses of earth. You can't do that in low earth orbit!

But just think of what it would mean to have a craft that could flit around the inner solar system with enough power to nudge asteroids! Just that technology alone could open up space travel!

[Bogey78O]

Gravitational pull is determined by mass and distance. Distanc eisn't much of a problem but you're going to have to have a lot of mass to get the asteroid moved in time unless we can get far away from Earth to alter it's pass before it gets close.

Seems unrealistic but a novel idea anyways.

[Danae]

A tractor of that magnitude would have to have a LOT of mass to make enough of a difference. Ping for later research

[capt. norm]

For our great grandchildren bumping asteroids might be something you do on a dull Saturday afternoon.

[fieldmarshaldj]

[Mad_Tom_Rackham]

Comes with previous crash experience.

[Unmarked Package]

A spacecraft of sufficient mass is sent to rendezvous with the asteroid and placed in a hover position to tow the asteroid with no physical attachment using just the micro-gravity attraction of the spacecraft mass as the towline. The gravity tractor, powered by nuclear-electric propulsion, would employ thrusters angled away from the asteroid to maintain hover distance and direction of tow.

The gravity tractor method is feasible if the threatening asteroid is detected early enough and at a sufficient distance from Earth. Based on calculations, it’s theorized that a 20 ton spacecraft could sufficiently deflect a typical 200 meter in diameter asteroid if given a lead time of 20 years. Deflecting a larger asteroid would require a spacecraft of greater mass or more lead time.

Whatever methods are employed to divert the trajectory of asteroids, early detection and better understanding of the objects are critical. That’s why there is great interest in funding increased efforts to explore known Near-Earth Orbit objects and search for presently undetected NEO objects.

[donna]

space tractor

Space barge!

[DBrow]

If you can bump them away, you can bump them in too.

This makes nuclear war look like a schoolyard fight.

Who would be in control of the technology?

[perfect stranger]

http://www.space.com/news/051103_asteroid_apophis.html

More info.....

Asteroid 99942 Apophis – first labeled as 2004 MN4 -- is estimated to be roughly 1,000 feet (320 meters) in diameter. Were it to strike Earth, it would not set off global havoc but would generate significant local or regional damage, experts say.

However

The ruin stemming from asteroid Apophis colliding with Earth would potentially be very great.

Indeed, the consequences, Schweickart suggested, would dwarf those seen as a result of the Indian Ocean tsunami in December 2004, hurricanes Katrina and Rita in September of this year, and the Pakistan earthquake last month.

[AntiGuv]

And for a bit further down the line: Recipe for Saving Earth - Move It.

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[isom35]

cant we just build a really cool laser? it would be more fun.

[jiggyboy]

Because the devastation would be great, the risk to a person of perishing in a major asteroid collision is about 1 in 10,000 or 20,000 over a 100-year lifetime - the same dying in a plane crash, Jedicke said.

I suspect that some very dubious and imprecise assumptions underlie the numbers in this probability calculation. How many asteroids? How big is each asteroid? Which year does each asteroid hit? How many people are in the area? Etc. Never mind that they're working from exactly zero previous similar events.

[lesser_satan]

But nuking them would be so-o-o-o much more cool!

[MistrX]

Why not just blow it to flinders?

[Calvin Locke]

The idea I heard is to paint it. I believe if you paint it black, it slows down, white, it speeds up.

You have to admit, it's low maintenance compared to other methods, once the job is done. Then it's up to the Sun to do its thing.

[RightWhale]

Mine it out so there won't even be a question of coming around to hit the planet.

[Kevmo]

Bump for later reading

[Joe 6-pack]

The technology has been around since the '70s....