[Black Wolf]

http://www.abc.net.au/news/2013-04-07/nasa-wants-to-tow-asteroid-to-the-moon/4614296

Very, very interesting. Potentially enormous benefits, but also kind of potentially very risky. I wonder if this will cause a stink in international relations? As much as NASA has a great reputation and solid history of super-accurate maths and engineering, depending on the scale of this thing, the idea of pulling any large masses around in the general direction of Earth is likely going to be greeted with... caution, given the potential damage done by miscalculation.

Although since this is the first time, hopefully they'll pick a small one.

[Nuke]

lets aerobreak apophis in earth atmosphere instead.

actually the thing about orbital mechanics is how easy it is to fudge things along. you can put it in a solar orbit slightly out of phase with the earth and then sync orbit slowly over time. when earths gravity is strong enough for capture you slow down and end up in a very high earth orbit. then you just do a hohmann transfer to the moon from there. this should be pretty safe, but would probibly cost more delta-v than shooting directly for the moon.

[Lorric]

I very much doubt there'll be any danger to the Earth at all. I'm sure they'll give the Earth the widest possible berth when making their calculations to bring the asteroid in.

[FreeSpaceFreak]

Yo dawg, I heard you like moons, so I put moons around your moon so you can... uh...

I'm wondering if this is the right way to go forward with space exploration though. Instead of humanity heroically venturing into deep space, this proposal basically entails bringing outer space closer to home so we can reach it more easily. Yawn. That's not gonna help us get to Mars... Or is anyone thinking of pulling this same trick on our red neighbour?

[watsisname]

I'm wondering if this is the right way to go forward with space exploration though. Instead of humanity heroically venturing into deep space, this proposal basically entails bringing outer space closer to home so we can reach it more easily. Yawn. That's not gonna help us get to Mars... Or is anyone thinking of pulling this same trick on our red neighbour?

You seem to be having some trouble recognizing the significance of this.

It is vitally important that we figure out methods for prevent asteroids from impacting the Earth.  Finding techniques for mining asteroids will also help us move forward in space exploration and is even potentially applicable to Mars colonization.  Towing an asteroid to the Moon helps to achieve both of these goals simultaneously.

[SpardaSon21]

Can't we just tow the asteroid to Earth orbit so we can mine the **** out of it?

[Flipside]

To be honest, the main test here, I think, is moving the asteroid, the mining of it will probably yield very little. The first experiment will almost certainly be a loss-maker, but hopefully the lessons learned from the exercise will make things easier in the future.

[watsisname]

I think if the only point was to move the asteroid then we wouldn't be bothering with bringing it anywhere near the Earth or Moon, but would rather do this in deep space.  Bringing it to the Moon seems to imply that we have things we want to do things with it later, such as mining it, or using it to threaten hostile dictators.

[Flipside]

Well, the biggest risk to the Earth mainly consists of NEO's, random external hazards like wandering planets and asteroids are much, much harder to deal with, simply learning to deal with those Near Earth Objects would greatly reduce the risk to the planet. The reason for bringing it to Earth where it can be controlled is two-fold. Firstly is the mining potential, the second is the unpredictability of just 'pushing it away', and hoping no other gravity sources will affect the new orbit.

If you take the map of NEOs - http://szyzyg.arm.ac.uk/~spm/, you'll note that there's quite a lot of asteroids out there, you'd have to be a pretty good shot to manage to actually push the target safely out of the way without the risk of it influencing other bodies.

Edit: Here's a closer X-Y view of the space near Earth itself...

http://szyzyg.arm.ac.uk/~spm/local_map.html

[watsisname]

Well yeah, there are hundreds of thousands if not millions of asteroids out there, but despite what the map looks like, space itself is remarkably uncrowded. 

We could take an Earth-crossing asteroid and move it into a non-Earth crossing orbit, and this would be an enormous reduction in impact risk for said object.  And the asteroid belt is actually a very dynamic place with asteroids hitting each other relatively frequently [on astronomical timescales, that is], as well as constantly being perturbed into new orbits by the gravity of Jupiter.  So changing the orbit of one belt asteroid has long-term effects that are inherently unpredictable, but is not any meaningful change from what the asteroid belt already is.

[Nuke]

at some point (such as right before the sun expands), we should throw all the asteroids at ceres, to give us a place to jump to when mars gets too hot.

[watsisname]

What would you hope to achieve by doing that?  Not only does it sound enormously impractical, but you'd end up with something with less than 5% the mass of the Moon.  Ceres alone accounts for about a third of the total mass of the asteroid belt.

[Nuke]

so we will throw a few comets at it too. oh and i meen all the asteroids, not just the ones in the asteroid belt.

[Lorric]

Humanity wants to be off this planet and on a new planet, preferably several new planets by the time the sun expands. But how long will be able to stay on this planet anyway before we ruin it and wipe ourselves out?

[NGTM-1R]

Can't we just tow the asteroid to Earth orbit so we can mine the **** out of it?

Because the possible screwups don't bear thinking about, while adding a crater to the Moon by accident isn't quite so big a deal.

[watsisname]

It'd be an asteroid small enough to breakup on atmospheric entry, but that could still wipe out a city.  I agree it would be best to not bring it into Earth orbit.

so we will throw a few comets at it too. oh and i meen all the asteroids, not just the ones in the asteroid belt.

I'd like to see you check the numbers on that idea.

Humanity wants to be off this planet and on a new planet, preferably several new planets by the time the sun expands.

The sun's already expanding, and has been since it became a main-sequence star.  
Even though the sun will not go into the red giant stage for about another five billion years, its increasing luminosity will render the Earth uninhabitable (unless we reduce solar insolation or something) within two or three billion years.  Over geologic timescales, the Earth's surface temperature has been moderated (more or less) by the amount of greenhouse gases in the atmosphere, but eventually this thermostat will fail when no more greenhouse gas can be extracted from the atmosphere, and at that point Earth's temperature will rise in accord with solar luminosity.

[Nuke]

so we will throw a few comets at it too. oh and i meen all the asteroids, not just the ones in the asteroid belt.

I'd like to see you check the numbers on that idea.

dont worry there will be plenty of debrits in the solar system by the time the sun explodes, i will see to that.

seriously though, we have how many billions of years to crack that problem? crash ice dwarves and small moons into it, build a backup planet. blast hunks off the moon and add those to it. the mass is there, we just need get it all in one spot. its likely more feasable than living in the vicinity of the gas giants.

[redsniper]

If you want to move one Earth mass worth of stuff way out that far.... just move the Earth.

[Mongoose]

Personally I think it's a bit premature to be assuming that our ancestors will still be kicking around a million years from now, let alone a billion.

[Nuke]

its entirely possible that the only technology we have to fight the growing sun is sticks. so we better get on it soonish.