Nukes Not the Best Way To Stop Asteroids, Says Apollo Astronaut 367
MajorTom writes "Right now, we are not tracking many of the asteroids that could destroy earth. But within the next decade, new telescopes will make that possible, and leave us with the tough decision of what to do about objects with an alarming chance of hitting our planet. Last year, NASA said that the best option is to nuke them. This week, Apollo astronaut Rusty Schweickart, explained that there are far better options, and he has started an organization to prove that they can work."
Test Trial (Score:2, Insightful)
I would think, if the "safety of the Earth/mankind" is at risk .... Shouldn't they be putting their theory to work? I'd want to make sure that a nuke CAN divert the asteroid in practice than reading about an academic debate or reading that NASA administrators/management reiterate probably incorrectly that their plan of action is the right way (as always and as government organizations always do).
Shouldn't there be an International Body finding a solution. The US isn't the only country with nukes, the right group of scientists, etc. etc. that can find a possible solution to this problem.
Re:Where to nuke? (Score:2, Insightful)
Just turning the asteroid into pieces wont work, the pieces will still come in the same direction.
But the pieces will have more surface area and therefore will burn up in the atmosphere more efficiently.
But what about using nukes as some sort of "propulsion" system (as in the Project Orion [wikipedia.org]), so they can change the direction of the asteroid? Wont be something for the last minute, but, could work?
That could work. Or we could change the direction of the Earth :P
Re:TFS (Score:2, Insightful)
Re:I always wondered (Score:5, Insightful)
You can rain nukes on that asteroid till it glows, but that won't make much difference. Trick is, in the vacuum of space, nuclear explosion is weak. There is no air to create blast wave and thermal flash, so all you get is some hard radiation and hand-grenade level of blast from vaporized bomb casing. And that's it.
Project Orion would get around this problem by using thousands of little charges, detonated close to the reflector - and it would still take years to accelerate.
A volley of the kind of nuclear warheads we have now would not effectively change course of any asteroid big enough to be a threat.
And blasting it to pieces would make a little difference, only in distribution of the damage - we'd get stoned with a swarm of fragments instead of one big piece, yet the same mass and total energy.
Why bother at all? (Score:5, Insightful)
The probability is vanishingly small we'll get crunchified and the likelihood of any bureaucratic solution even working is also damn low. So let's just accept that there's a nonzero probability that we'll all get wiped out. Worst case we all die someday anyway.
Re:Simple answers become complex... (Score:1, Insightful)
For ANY noticeable populsion, burying them is the ONLY option. Otherwise you will just make a fireworks show for Hubble to watch.
Actually I think the best way would be to send a nuke in large tank of water, contact fused. Evaporated water would create a blast wave that might have some effect. Just remember to calculate all aspects of the mission in the same units...
A trivialized problem (Score:3, Insightful)
Not exactly what TFA is talking about, but I dislike how the very real threat of asteroids is trivialized in the public mind. Every time astronomers discover a remotely threatening asteroid, anything that hits 1 on Torino scale, journalists warn of a dangerous collision that could wipe out a continent, yadda yadda, while further observation of the asteroid over the next weeks shows that there's no chance of collision. So the public hears these stories about asteroids at least once a year and many thus think that it's a bogus threat because, oh, whenever journalists warn of a possible collision it turns out to be a non-threat, so it will never be a threat, right?
Makes me wish that journalists would just shut up about any objects lower than 3 on the Torino Scale.
Early detection by far best option (Score:3, Insightful)
Re:He's got a point - why nuke the asteroid? (Score:4, Insightful)
This got an insightful. I'm not sure to be proud of the mods for modding up a great bit of satire, or ashamed at how they did it.
Re:Alternative sugestion (Score:3, Insightful)
Assuming this is even possible what are the chances of the asteroid's orbit decaying and having it plummet to the earth anyway?
Probably quite similar to the chances of the Moon's orbit decaying and having it plummet to the Earth, if we set it up right.
Re:Why bother at all? (Score:3, Insightful)
Actually the probability of an impact over a relatively large interval of time is quite high. It is only over small intervals of time, geologically speaking, that the probability is small.
Would the Apollo program qualify as a bureaucratic endeavor? I think you would be surprised how well people cooperate when they feel their civilization is in jeopardy.
As for just accepting that nonzero probability, we must all do so on some level. Even if we eventually have a good asteroid tracking program in place, there are no guarantees that we'll detect a large asteroid in time to mount an effective response. However, I think we should still try since it will decrease the probability that we'll get caught off guard. Conscious life may well be be a rare thing - I don't think we should simply cast it away without a thought.
Re:He's got a point - why nuke the asteroid? (Score:5, Insightful)
Re:He's got a point - why nuke the asteroid? (Score:2, Insightful)
Troll? Why isn't this modded funny? It's hilarious.
Re:I always wondered (Score:1, Insightful)
"we'd get stoned with a swarm of fragments instead of one big piece, yet the same mass and total energy."
By breaking the asteroid into multiple pieces you dramatically increase the surface area to volume ratio.
If we could reduce an asteroid to space dust, we will all survive.
Re:The reason for nukes (Score:5, Insightful)
You appear to misunderstand:
1. How much power is needed to apply an appropriate vector to the Significant (capital S is appropriate) mass.
2. The method used to propagate the blast energy into the asteroid.
The first item depends on the size of the asteroid, but the killers are usually pretty big, and need a big push. The amount of push depends on where in the orbit you find it, of course.
The second item is basically this: You can't rely on the atmosphere to transmit a 'shockwave' to the asteroid. In a vacuum, the actual shockwave is negligible once you get too far away (inverse square) and even up close, is only comprised of the limited mass of the bomb. Again, negligible effect. The actual propulsion comes from mass ejected by the asteroid itself. What would compel said mass to depart fast enough to create a thrust vector? Why, how about the sudden massive heating of one side? With a hydrogen bomb, you get the energy needed. For devices in the 15-20KT range, you're talking atomics, and the amount of usable energy that can be imparted is reduced significantly.
So the job of the bomb is not so much to "blow the asteroid off course", it is to convert the asteroid into a rock-rocket that fires molten asteroilava in one direction to create a vector for the larger mass in another.
Why don't we try it? (Score:3, Insightful)
Wouldn't it make sense to try it as an experiment to gather hard data on how different types of asteroid react and as an excercise in examining the logistical problems and actual effect from a practical perspective?
It may make sense to have a gun, but if you don't know *which* gun to use...
Re:It depends on the timing... (Score:2, Insightful)
My point was that the distance required when such small deflections becomes a major hinderance to the mission. If we are planning to intercept an asteroid many months (years even) from impact we should be planning to do so well outside our solar system. This may mean we would need months or years for the intercepting weapon to reach the asteroid... not to mention the pre mission planning etc.
With all that (very vague argument) done, I would have speculated that the obvious "best" solution is to have a capability that can operate within a number of weeks of impact (or a few months). Not only does this allow response to late detections, but all asteroids travelling extremely quickly. Further more, there is less chance of some mishap occuring during the interception flight wich would also be much shorter. This would also make manner missions easier if humans are required for any part of the mission.
So I happily accept that a nuclear option may work, but if a shorter range and easier/faster to deploy option is available I would see it as preferrable.
Re:Alternative sugestion (Score:3, Insightful)
Actually, there's no need to put it into a geosynchronous orbit. There are lots of circumsolar orbits that are more favorable (and safer) than a circumterran orbit.
Bringing large, potentially unstable masses close to the earth is a mistake. You wouldn't want the asteroid to fragment during a maneuver and accidentally impact something important. Like the Mediterranean Sea, for instance.
Do your mining out near the earth-sun L4 or L5 point and bring the packaged extraction products into earth orbit via solar sail. And the L4/L5 points aren't really necessary either. There are all sorts of AAA orbits that will give you regular, low-cost payload transfers from the asteroid to the earth-moon system. The L4/L5 points might be attractive because they would be convenient places for habitats or other space industries (and therefore be resource concentrations for solving problems, etc.)
Moving an asteroid from an earth impact orbit to a "close call" orbit is a major undertaking, but not impossible or even particularly complex. Having a space-based resource extraction industry in operation would make it a LOT easier to get done. You'd have engines, fuel, solar sails, large solar furnaces, equipment to stabilize a poorly cemented asteroid: all of the things needed to get the job done. And the space-based resource industry could also solve several other pressing needs: orbiting solar panels are not economical to launch (they never pay back the power required to launch them), but they are economical to build from material in space, advanced battery chemistries needed for mass adoption of electric vehicles are running into resource shortages in cobalt, nickel, tantalum, etc.
Re:I always wondered (Score:5, Insightful)
For a small object, yes.
For a object big enough to seriously worry about, no. Think of it this way. Take a rock the size of the one that killed the dinosaurs. It had roughly 300 million nuclear weapons worth of energy. Break it into a million equal size pieces, and there are a million rocks with 300 times the energy of a nuclear weapon, each of which would be more than large enough to punch through the atmosphere. The damage would be more focused on the surface of the Earth, and less would be "wasted" on deep layers of rock.
Small explosions are much more effective at destroying things than large explosions. That's why cluster bombs were invented.
Re:TFS (Score:5, Insightful)
If you know how to do it, I think NASA would be extremely interested in your solution. 3000 metric tons to Low Earth Orbit (LEO) is a lot more than anyone has ever attempted before. The most powerful rocket in existence will be the Ares-V upon completion. It will be capable of lifting ~180 metric tons to LEO. Now scale that up by about 17x and we'll be good to launch an Orion.
Re:TFS (Score:5, Insightful)
Really. I can't believe geeks would think that fabrication in space is impossible.
Re:Then What Do We Nuke? (Score:3, Insightful)
You know what's funny?
In the movie everyone will be discussing below, several proposals were bandied about to use gentler methods to move the asteroid.
The problem with every method but nukes was that they worked too slowly to be of use when the asteroid is already close and just days from impact.
If we can plot the course of an asteroid and discover years in advance that it's going to hit us, a tiny rocket mounted on the surface and fired at an angle would be enough to solve the problem. The difficulty is with calculating the trajectory far in advance because every other object who's gravitational field extends into the asteroid's path changes that path.
So for anything but nukes to help us, we would have to track not just the object likely to hit us but every object that it could come close to between now and the date of impact.
Re:Mod this junk down (Score:3, Insightful)
I don't know for sure, but back in the 80s here in the UK it was common knowledge that in the event of a nuclear attack launched by Russia we'd have 4 minutes warning. Quite how that came to be common knowledge and how accurate it is I don't know, but I suspect that you're right, and that even a ground/sea based launch isn't going to give a country a whole lot of time to retaliate.
On the other hand though, a space-based launch is presumably going to give less time (who looks up?) and, assuming multiple powers have nukes in orbit, at least some plausible deniability as to who is responsible.
Re:He's got a point - why nuke the asteroid? (Score:3, Insightful)
Re:It depends on the timing... (Score:3, Insightful)
Yeah, blowing up (as opposed to imparting a net impulse) such a rubble-pile-type asteroid with a nuke would slightly disperse it temporarily, after which it would largely reassemble under its own gravity and continue on its old course (center of mass etc..), only now its radioactive as hell...
With a hard and rocky asteroid the nuke might fragment and disperse it effectively enough for the fallout to be worth it, but we better have some more tricks up our sleeve for the other types.