The Plan to Bring an Asteroid to Earth

[n2doc]

By Adam Mann


PASADENA, California — Send a robot into space. Grab an asteroid. Bring it back to Earth orbit.

This may sound like a crazy plan, but it was discussed quite seriously last week by a group of scientists and engineers at the California Institute of Technology. The four-day workshop was dedicated to investigating the feasibility and requirements of capturing a near-Earth asteroid, bringing it closer to our planet and using it as a base for future manned spaceflight missions.

This is not something the scientists are imagining could be done some day off in the future. This is possible with the technology we have today and could be accomplished within a decade.

A robotic probe could anchor to an asteroid made mostly of nickel-iron with simple magnets or grab a rocky asteroid with a harpoon or specialized claws (see video below) and then push the asteroid using solar-electric propulsion. For asteroids too big for a robot to handle, a large spacecraft could fly near the object to act as a gravity tractor that deflects the asteroid’s trajectory, sending it toward Earth.

“Once you get over the initial reaction — ‘You want to do what?!’ — it actually starts to seem like a reasonable idea,” said engineer John Brophy from NASA’s Jet Propulsion Laboratory, who helped organize the workshop.


more

http://www.wired.com/wiredscience/2011/10/asteroid-moving/

[Denninmi]

1. Because, hey,

What could possibly go wrong?

[TheMadMonk]

18. Very little actually. The forces involved are ALMOST vanishingly...

...small and act over a very extended period of time.

Whilst it is a mathematically trivial task to deliberately direct an asteroid onto a collision course with the Earth, it's not something at all likely to come about as a result of accident and happenstance. And in fact it is almost equally trivial to "chart" an orbit which makes collision impossible under any possible (or even achievable) failure scenario.

Worst case scenario is a lost mission. And likely that loss only partial, since orbits are ALL ABOUT "what goes around comes around". A properly timed recovery mission is likely to prove considerably cheaper than the original.

THAT, may be the single biggest argument against manned missions, rescue is a time critical, and all too likely impossible task. A half botched robotic mission can wait twenty years for an orbitally optimal moment.

On the other hand, a sentient hand on the spot can overcome a 5 cent failure.

Personally I favour immediate risk over long term surety.

[tgearfanatic234]

20. Excellent post

[ret5hd]

2. WOW! Then we could have a low-gravity orbiting platform to base...

future space flights from! Wait, don't we have a moon?

[Occulus]

15. The Moon really isn't all that convenient for a variety of reasons.

You might think so, given its location, but that's not the case. It's either in the wrong position, or the gravity well of the Moon makes it impractical, or a number of other reasons.

It's far more practical to put a rock exactly where we want to use it, closer to Earth.

[HopDavid]

22. Tiny rock not that helpful

The 4 day work shop looked at moving a rock two to five meters in diameter.

A rock this small wouldn't help much as an orbital platform.

Further, asteroid resources are still unknown. To get a good inventory of asteroidal resources would take many prospector probes.

But the moon has a large of body of resources. In comparison to what we know of asteroids, much better characterized.

In terms of aiding space travel, volatiles which can be made into propellant are of the most value.

The moon evidently has sheets of ice two meters thick in the polar cold traps.

[dtexdem]

3. Didn't the dinosaurs try that?

;-)

Yeah, it might ultimately be an important industrial idea. But I have about as much faith in this being done by current governments and corporations using current technology as I do in the nuclear power industry. And a screw up with this could far outdo nuclear accidents as a threat to human life on this planet.

[ret5hd]

4. This could bring a whole new meaning to the phrase "dropping the ball".

[leftyohiolib]

5. sounds like the dumbest of dumb ideas? is brownie now in charge of nasa?

man's arrogence is showing,again

[Occulus]

14. You need to understand that most asteroids aren't a Ceres or a Vesta.

Many of these rocks are about the size of a boulder. Many more are dust-sized. Most are of no danger, there or in Earth orbit.

[Fumesucker]

6. A spacecraft massive enough to significantly deflect an asteroid simply by its gravity?

:wow:

If we had a spacecraft that big we wouldn't need the damn asteroid..

:crazy:

[phantom power]

7. Not massive. Just slow.

[Fumesucker]

10. Unless the damn thing masses far more than anything we have put in space yet..

It's going to take geological ages to significantly change the orbit of an asteroid by gravity from a spacecraft.

[Occulus]

13. Depends on which asteroids you're talking about.

Ceres and Vesta, yes. Those are huge. But many of the "normal" sized rocks out there really aren't all that massive, ranging down to a dust particle in size, and altering their orbits using the gravity of another body to 'nudge' them into an orbit that would allow the Earth to capture them (or by any of a number of other, more direct methods) really isn't far-fetched at all. All it would take is a very very slight change in their orbits from very far away, and would take a matter of years, not ages. As the OP says, we have the technology to do this right now.

[txlibdem]

21. that is only one possible option for guiding an asteroid to us

And by the way, even a pebble-sized rock would exert a tiny, almost imperceptible force on a much larger asteroid. The opposite is true. That's why I don't like the gravity/mass method of deflecting asteroids: the ship would be drawn toward the asteroid and would need to use fuel to maintain the proper position in relation to the asteroid.

I'd strap a few VASIMIR plasma rockets to the asteroid and fire them in proper sequence to slow the orbit of the asteroid. Slower orbit equals closer to the Sun (and therefore the Earth). It would take years but the great thing about a VASIMIR rocket is that it uses very little fuel to get the job done. Chemical rockets expend all of their energy in the first few minutes. A VASIMIR rocket would exert a small push continuously for as long as needed, maybe a decade or more.

[immoderate]

23. VASIMIR is something my grandmother would say after, "Oy!..."

Otherwise I don't know what it is. I guess plasma implies a low mass and very high velocity.

Actually I have had asteroid mining on my mind, but more concerning the long term entropy situation at the earth's surface. Asteroids may have deposits of pure metals or minerals or water that may become increasingly difficult to reclaim at the surface, and space mining may become a cost effective method of "recharging" the earth-battery.

--imm

[RedCloud]

8. This plan is sponsored by the little creatures of the planet.

It's time to evolve into bigger organisms they claim.

[FiveGoodMen]

11. !

:rofl:

[struggle4progress]

9. Asteroid crash: Spectacular 'fireball' display expected

23/09/2031
The thousand-ton asteroid hurtling towards earth could give stargazers a spectacular 'fireball' display tonight moments before it crashes ... Scientists say they will have just 20 minutes to warn people exactly where the thousand-ton, five billion year-old asteroid will crash ...
http://www.mirror.co.uk/news/top-stories/2031/09/23/asteroid-crash-to-see-spectacular-fireball-display-115875-23441369/

Sep 9, 2031 2:42pm
Asteroid Falling to Earth: Will You Be Hit?
... Meteorites fall all the time, but most of them burn up as they descend into thicker layers of air. This asteroid, though, weighs a thousand tons, and experts say a million pounds of iron-nickel chunks could well make it down to the surface ...
http://abcnews.go.com/blogs/technology/2031/09/asteroid-falling-to-earth-will-you-be-hit/

[eppur_se_muova]

12. Pick the densest nickel-iron fragment out there ...

and there may never be another open-pit mine on the Earth's surface.

[A Simple Game]

16. Aww, a baby moon. Can we name it after me? n/t

[pokerfan]

17. Can we call it Demon's Run?

Please please please please please please please....

[txlibdem]

19. Just aim it toward one of the 5 Lagrange points of the Earth and Moon

The gravitational forces will keep anything but a very fast moving object from escaping.

So as another poster said: we're in NO HURRY. Bring it in nice and slow and right on course... no problemo.

PS, we need to start mining the asteroids so we can build space stations and colonize the moon and mars. Far cheaper to expend a few kilograms of plasma fuel to nudge an asteroid to come here versus blasting all the components, shielding (dirt or water) and O2 up from the surface of either the Earth or Moon.

Two thumbs up from me!

[HopDavid]

24. It takes propellant to park at an L region

Something slowly coming into an L region also slowly leaves, in general.

Objects parked at L1, L2 and L3 regions are like balls on a hill top. If balanced perfectly, they can remain at the top. But a slight nudge will send them rolling away from the hill top. In the earth moon system, there are constant perturbations so it requires station keeping propellant to keep them in these locations.

L4 and L5 are somewhat more stable. But it would take delta V to park an asteroid at these locations. You couldn't just toss an asteroid towards L4 or L5 and expect it to settle there.

The earth moon L4 and L5 are far up earth's gravity well and therefore vulnerable to perturbations from the sun. Keeping objects there would also require station keeping.

The closest L region to earth is the Earth Moon L1, aka EML1. The L4 and L5 are 1 lunar distance from earth. Earth, Moon and L4 or 5 form the vertices of an equilateral triangle.