Capturing an asteroid

[Seggybop]

Pretty often there are asteroids that pass relatively close to the Earth, but continue on back out into space.

Say one of these asteroids, this one about a half mile across, is going to pass Earth at around the distance to the moon. And then all the nuclear missiles that USA has are shot at it to explode in front of it in the direction that it's going.

Would doing this be able to slow the asteroid enough for Earth gravity to capture it and keep it as a moon? Would it be halted too much and fall down onto the planet? No effect? What happens?

[The Black Jesus]

you cant slow that down enough once it reaches a certain proximity

however, you might consider ramming something into it when its at a safe distance

[Raptor 597]

Actually, within the next 10 years. 2010 I elieve NASA said we would land on an asteroid for samples. And for the detonation too be effective you need the speed, fuel, and exact calculation of the distance of the explosion.

[Darth Wong]

If you mess up an attempt to redirect an asteroid into a captured orbit, you might make it hit you. This seems like a bad idea.

[jaeger115]

The only reliable way to successfully deflect an asteriod is to intercept it when it's still 120 years from hitting Earth. No space engine is powerful enough to push an asteriod that big out of the way in a short time.

[ArmorPierce]

No, you are more likely to make it end up either hitting the Earth or just continuing on. Why would you even want to do that?

[SyntaxVorlon]

There really would be no reason to capture an asteroid as there are thousands of tons of usable materials in earth orbit now, including extinction level asteroids. If you wanted to really capture an asteroid you could, if it is big enough, hollow out the inside, turn the whole thing into a giganitic maglev ring, and have a groundbased or moon based mass driver fire large blocks of magnetic metal, steel, iron, nickel, etc., using the ring to deccelerate the block as it passes through the ring, transfering relative momentum. Do this enough times and you can slow down to a reasonable orbiting velocity.

[Darth Wong]

That's much too complicated; it would be easier to simply detonate nukes in front of it.

[Seggybop]

Why would you even want to do that?

The plan is to have the asteroid orbit the planet so that it can be easily mined out. Then the materials gained from it would be used to construct various things in space, and the then hollowed asteroid would be used as a base.

[Darth Wong]

You would risk an asteroid impact on the Earth so you can mine its resources? Why not mine those resources from Earth, which is much, much easier, safer, and cheaper?

[Seggybop]

You would risk an asteroid impact on the Earth so you can mine its resources?

No, probably not. But only imagining idiotically dangerous and extravagant things like this doesn't screw anything up.

Why not mine those resources from Earth, which is much, much easier, safer, and cheaper?

So that the material doesn't have to be launched into space afterwards, and so that afterwards there's a hollow asteroid left over that could be used as some kind of space station.

[SeebianWurm]

And voila, the collision of 2150 becomes reality and Allegiance is borne unto the stars.

[Darth Wong]

Why not mine those resources from Earth, which is much, much easier, safer, and cheaper?

So that the material doesn't have to be launched into space afterwards, and so that afterwards there's a hollow asteroid left over that could be used as some kind of space station.

You have to launch a great deal of material into space in order to slow down the asteroid and capture it in the first place, and an asteroid would make a shitty space station. You have no control whatsoever over its material properties, microstructure, etc.

[Seggybop]

You have to launch a great deal of material into space in order to slow down the asteroid and capture it in the first place,

In an article I read about a plan the government had to set off a nuclear bomb on the moon, it was stated that an ICBM was capable of exploding within 2 miles of a target on the moon. Since there are supposed to be thousands of ICBMs, I figured it wouldn't take that much more effort to send them out to explode in front of the asteroid.

and an asteroid would make a shitty space station. You have no control whatsoever over its material properties, microstructure, etc.

I didn't think of that, watching too much of the Gundam stuff I guess.

[Darth Wong]

In an article I read about a plan the government had to set off a nuclear bomb on the moon, it was stated that an ICBM was capable of exploding within 2 miles of a target on the moon. Since there are supposed to be thousands of ICBMs, I figured it wouldn't take that much more effort to send them out to explode in front of the asteroid.

I don't know who wrote that article, but ICBM's cannot escape Earth gravity. They make sub-orbital BALLISTIC trajectories.

[kojikun]

Youre discounting the possibility of using NTRs from a great distance, or an orion type sitation, still while its a good distance away mind you.

[Seggybop]

I don't know who wrote that article, but ICBM's cannot escape Earth gravity. They make sub-orbital BALLISTIC trajectories.

http://www.space.com/news/spacehistory/ ... 00514.html
http://www.commondreams.org/headlines/051400-02.htm

[Darth Wong]

Ah, so they designed and built the Saturn rockets at enormous expense for nothing, since garden-variety ICBM's could do it? I'm sure they only meant that it could be done in theory with ICBM technology, not actually taking a stock ICBM and simply targeting it at the moon.

[Enlightenment]

There really would be no reason to capture an asteroid as there are thousands of tons of usable materials in earth orbit now, including extinction level asteroids.

This will come as news to damn near everyone with anything more than a passing interest in space settlement or commercial space activity. The only thing orbiting the earth that even remotely resembles a collection of usable materials in thousand ton lots is the moon. Other than the moon, Earth has no natural satelites and as such, orbit is absolutely barren.

http://www.space.com/news/spacehistory/ ... 00514.html
http://www.commondreams.org/headlines/051400-02.htm

Even if the stories are true (and they might very well be), the ICBM comment is pure bullshit. ICBMs don't have anywhere near the delta-v to get anything to lunar altitude or lunar orbit. The press got it wrong.

[jaeger115]

Why the fuck do you think missiles designed for BALLISTIC flight must all of a sudden have the delta-V to fly into space?

[SyntaxVorlon]

There really would be no reason to capture an asteroid as there are thousands of tons of usable materials in earth orbit now, including extinction level asteroids.

This will come as news to damn near everyone with anything more than a passing interest in space settlement or commercial space activity. The only thing orbiting the earth that even remotely resembles a collection of usable materials in thousand ton lots is the moon. Other than the moon, Earth has no natural satelites and as such, orbit is absolutely barren.

You could not be more wrong.

Earth has two other known moon-type satalites and numerous asteroids in far orbit. Too far away for decay to be a problem but close enough to be a resource. Unless you were un awary the Moon is the product of a collision between a much larger protoEarth and a smaller, faster rock that collided with the earth and split off to form the moon. During this collision plenty of rock was thrown around, a lot of that is in orbit today. A good deal of rock has been drawn into orbit as well over the past 4.5 billion revolutions.

And if you want to deal with all the environmentalists who would be angry with the idea of a nuclear bomb in orbit around the earth, no less the UN, you would be better off setting up a mass driver. You've said it yourself that very little KE would be transfered by a space detonated nuke, and a mass driver and asteroid based maglev deccerator set up would be able to do the job at a much smaller cost, though probably only if the MD was on the moon.

[Crown]

I don't know who wrote that article, but ICBM's cannot escape Earth gravity. They make sub-orbital BALLISTIC trajectories.

Ahh, just off the top of my head ICBM's are capable to 'reach orbit' however prohibated by some treaty or another so that they are forced to follow ballistic trajectories (30min travel time) instead of faster LEO. It was something that was bashed out between the USA and USSR back in the day. Remember the first ICBM was the same rocket that launched Sputnik

But as to capture an asteroid on course to Earth one would want to speed it up, rather than slow it down. This is using simple Keplernian orbit mechanics. Of course this is nulled it the asteroid is on a hyper-bolic trajectory, then the prudent thing would be to either speed it up so that it doesn't hit us, knock it out of the way so it doesn't hit us, or hide in a very deep hole with years worth of food supplies

[Enlightenment]

You could not be more wrong.

Burden of proof time. Cough up some cites.

[Crown]

I think that SyntaxVorlon is talking about the Apollo-Armor asteroids, although how these pebbles (relatively speaking) suddenly qualify as 'moon-type' sattelites is beyond me

[Enlightenment]

The Apollo and Amor groups are earth crossing asteroids. They orbit around the sun and are in no way satelites of Earth.

Permanent has a 2D orbit overview online: http://www.permanent.com/a-geolog.htm