No need to send Bruce Willis into space with a nuclear bomb -- the best way to deal with a killer asteroid hurtling toward Earth could be a "gravity tractor."
Two NASA astronauts, gently mocking the solution offered in the Hollywood blockbuster "Armageddon," have come up with a deceptively simple plan to pull asteroids off course.
Edward Lu and Stanley Love have proposed that a rocket be launched into space, effectively to act as a giant magnet.
Landing on an asteroid, which is no more than a spinning pile of rubble, is very difficult to achieve.
Instead, the gravity tractor would travel alongside the asteroid and gradually pull it off course, using nothing more than the gravitational pull between the two bodies.
"This saves you from having to land on the asteroid and then trying to stabilize yourself on a flying pile of rock and debris which is spinning all the time," Love told Reuters after their plan was published on Wednesday in the science journal Nature.
Lu and Love calculated that, with sufficient warning, a 20-ton gravity tractor could safely deflect an asteroid 200 meters across in about a year of towing.
"By using gravity as your tow line, you can sidle up to an asteroid. Maintain it for a year and that should give it enough nudge to miss the earth 20 years later," Love added.
The clock is ticking on the chance to put their plan into action.
An asteroid is due to pass close to earth on Friday, April 13, 2029. But the chances of impact are put at comfortingly long odds of 5,560 to one.
"We know enough about this asteroid to know it is a potential threat but we still have a few more years to watch this thing and get a better handle on what it is going to do," Love said.
"No panic. I am not losing any sleep over it. But we have to make a decision by 2013 on whether we have to send a mission to detect it," he added. "Detection and deflection go hand in hand."
In the movie "Armageddon," a doomsday asteroid is on a collision course with Earth and the only way to knock it off course is to drill into its surface and detonate a nuclear bomb.
Bruce Willis springs to the rescue as the countdown begins on life as we know it.
For Love, it was no more than an enjoyable night out.
"It is a great movie and a lot of fun -- but check your brain at the door. Most of what they show about asteroids and space ships is pure Hollywood," he said.
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My favorite part of Armageddon is that it seems like (even pretending that a nuke could blast Texas in half) the halves of the asteroid should slam into each other on the other side of earth, creating an Endor Holocaust effect.
Deep Impact was better, not that that's saying much.
PS, how do we keep the graviatic towing vehicle in place for 20 years? Seems like that would take a good bit of fuel. (on reflection, it would take exactly as much fuel as would be needed to move the asteroid far enough to miss Earth with 20 years to do the work, but that still seems like a good bit. Actually, it would take more because you would have to point the jets away from the asteroid's face so they don't ruin everything.)
Sriad wrote:Deep Impact was better, not that that's saying much.
Maybe the science of Deep Impact was better, but definitely Armageddon was a better movie. Deep Impact seemed to be a collage of characters that you didn't really care about.
Would as small a mass as a rocket even have the gravitational pull to even significantly affect an asteroid let alone deflect one?
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Anomie wrote:Would as small a mass as a rocket even have the gravitational pull to even significantly affect an asteroid let alone deflect one?
*ahem*
Lu and Love calculated that, with sufficient warning, a 20-ton gravity tractor could safely deflect an asteroid 200 meters across in about a year of towing.
How the fuck are they going to build a 20 ton ship in 30 years? They'd have to build it in space, so they'd need to throw all their equipment up there first.
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wolveraptor wrote:How the fuck are they going to build a 20 ton ship in 30 years? They'd have to build it in space, so they'd need to throw all their equipment up there first.
..at least it's a kind of motivation to build space technology and assets, hrrm? Of course, the current Government would never pass it. The Rapture's happening tomorrow, you know.
Then again. I hope this can be of use against the Goa'uld too.
CaptainChewbacca wrote:A twenty-ton rocket eh? This looks like a job for PROJECT ORION!
While impressive, twenty tons is not nigh impossible. It's only 1/3 more than the Apollo lunar module, and less than half the total Moon-payload capacity of Saturn V. It's not really particularly more spectacular than what has been done before--the problem is that nothing like it has been done recently. There are no operable Saturn Vs to save the day, or anything comparable (at least as far as I'm aware of).
Yes, because a twenty-ton spaceship would be SUCH a stretch from the current shuttles, or the moon lander rockets...or not.
The Shuttles can carry a 28.8 ton object into orbit in the cargo bay, according to the NASA stats.
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Hotfoot wrote:Yes, because a twenty-ton spaceship would be SUCH a stretch from the current shuttles, or the moon lander rockets...or not. The Shuttles can carry a 28.8 ton object into orbit in the cargo bay, according to the NASA stats.
Compared to shuttles, undoubtedly. The shuttle's capability to put objects into low-earth orbit is hardly comparable to Saturn V's capability to put them into lunar orbit, much less delivering payloads into the far interplanetary space. The difference in gravitational potential between LEO (ISS-level) and Moon's orbit is something on the order of 5.8e7J/kg, which is about 18 times greater than the difference between LEO and ground. That's the kind of gravitational well one would have to climb out.
Fair enough, but to assume that an object of such size would HAVE to be built in space irritates me. It's certainly not a stretch to get something that mass into orbit in the first place.
I'll handily admit that I don't have the hard numbers behind what would be needed, but one would imagine such a project would be far less expensive than, say, a manned mission to Mars, and much more plausible.
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Kuroneko wrote:While impressive, twenty tons is not nigh impossible. It's only 1/3 more than the Apollo lunar module, and less than half the total Moon-payload capacity of Saturn V. It's not really particularly more spectacular than what has been done before--the problem is that nothing like it has been done recently. There are no operable Saturn Vs to save the day, or anything comparable (at least as far as I'm aware of).
Oddly enough, the shuttle replacement project NASA is working on is capable of this (on paper, granted).
CaptainChewbacca wrote:A twenty-ton rocket eh? This looks like a job for PROJECT ORION!
This is nothing compared to Orion, the biggest version designed that was "buildable with materials and techniques that could be obtained or anticipated in 1958" massed 8 million tons.
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CaptainChewbacca wrote:A twenty-ton rocket eh? This looks like a job for PROJECT ORION!
Considering we just had a fucking thread about Orion, and outlined that it was only any good for a ten thousand or up craft when launching from the ground, it speaks volumes that you would make the above statement.
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Hotfoot wrote:Yes, because a twenty-ton spaceship would be SUCH a stretch from the current shuttles, or the moon lander rockets...or not. The Shuttles can carry a 28.8 ton object into orbit in the cargo bay, according to the NASA stats.
Compared to shuttles, undoubtedly. The shuttle's capability to put objects into low-earth orbit is hardly comparable to Saturn V's capability to put them into lunar orbit, much less delivering payloads into the far interplanetary space. The difference in gravitational potential between LEO (ISS-level) and Moon's orbit is something on the order of 5.8e7J/kg, which is about 18 times greater than the difference between LEO and ground. That's the kind of gravitational well one would have to climb out.
Whats interesting is that only 7% of the energy is required to lift to that height but 93% is required to accelerate to orbital velocity so it stays there.
It also depends on what type of orbital transfer you use a direct shot requries that most energy while a a Hohmann transfer uses quite a bit less energy but takes a lot longer. Also there is even a other type of maneuver that uses even less enery used by the Japenese Hyten mission http://www.cds.caltech.edu/~koon/papers ... he%20moon'
