New Best Way To Nuke a Short-Notice Asteroid 311
doug141 writes "A scientist proposes the best way to deal with an asteroid on short notice is to hit it with an impactor, followed by a nuke in the crater. From the article: 'Bong Wie, director of the Asteroid Deflection Research Center at Iowa State University, described the system his team is developing to attendees at the International Space Development Conference in La Jolla, Calif., on May 23. The annual National Space Society gathering attracted hundreds from the space industry around the world.
An anti-asteroid spacecraft would deliver a nuclear warhead to destroy an incoming threat before it could reach Earth, Wie said. The two-section spacecraft would consist of a kinetic energy impactor that would separate before arrival and blast a crater in the asteroid. The other half of the spacecraft would carry the nuclear weapon, which would then explode inside the crater after the vehicle impacted.'"
Don't asteroids rotate? (Score:3, Insightful)
Even with a small rotation your nuclear bomb would miss the crater without some extra guidance which is not shown.
Re:But Why? (Score:5, Insightful)
because it's less expensive than rebuild a city?
Re:But Why? (Score:5, Insightful)
It's not DESTROYING the incoming asteroid, it's breaking it up into smaller pieces and changing their trajectory. The point isn't to get the asteroid to miss us entirely, it's to make it not hit us all at once in one spot.
Small impacts would probably be pretty devastating for those that survive the atmosphere(think early impacts from Armageddon, etc) but at least it wouldn't cause a near-extinction of all life as a giant single impact could.
Re:how short is the notice? (Score:4, Insightful)
If we're facing a potential wipe-out of several major coastal cities, I'm hoping we would get some leeway on expenses.
Probably not though. :(
I'm sure we would still be fighting over who would pay for it, or some other political bullshit [theonion.com] when it hit and killed us all.
Re:Don't asteroids rotate? (Score:5, Insightful)
What, you think someone smart enough to design a mission to intercept an asteroid with an impactor and hit that crater with a nuke wouldn't know to take the spin into account?
All this study was doing is working out whether the idea would work, not designing a complete mission profile for a specific asteroid.
Re:how short is the notice? (Score:5, Insightful)
Nonsense. You'd just use the asteroid *itself* as fuel.
That's what the nuke does. The asteroid provides fuel (as in mass), and the nuke provides the energy.
Re:But Why? (Score:4, Insightful)
Re:Don't asteroids rotate? (Score:2, Insightful)
If we have a 1% risk of a rocket detonating during launch there might be reason to design a mission that only sends two rather than 1000.
Re:Simulate or it didn't happen! You know what I m (Score:4, Insightful)
Re:But Why? (Score:5, Insightful)
Actually if you break a large object into many small objects the pieces still have the same total kinetic energy.
It isn't the kinetic energy in space that's the problem. The problem is the kinetic energy at point of impact with the earth's surface.
If you spread that same energy out over hundreds (or perhaps thousands) of miles instead of one small impact crater, there is a very real qualatative difference. Not to mention the fact that the more surface area per mass an object has, the more of it will burn up in the atmosphere (further disspating the kinetic energy it had in space). Small objects tend to burn up completely.
Think about it this way: Would your property fare better in a hailstorm with thousands of pea-sized hailstones hitting your yard, or just one large hailstone with the same total mass?
Re:But Why? (Score:4, Insightful)
I guess it will heavily depend on the asteroid.
Most certainly. No objection here.
Remember that a nuclear explosion is not that big. Without an atmospheric shock wave by suddenly heated air and with an asteroid not that scared about radioactivity, for many asteroids a nuclear bomb might have hardly any effect.
I'd disagree here. With a moderately underground burst, a substantial mass of the asteroid (compared to the mass of the nuke - not compared to the mass of the asteroid, of course!) gets vaporized. Please remember that this is the mode in which a nuke airburst creates a fireball: The air is heated into incandescence by an extreme flux of X-ray radiation. In solid matter, the exponential falloff of the X-rays happens over a smaller distance, but you still evaporate a lot.
If you do it on the surface or a few meters underground, you'll probably waste a lot of the energy. You'll get a lot of high temperature plasma, but the mass will be still quite low. What you should be aiming for (pun intended :-)) is a detonation depth sufficient to create a substantial mass of solid ejecta propelled by the explosion in (mostly) one direction such that their speed won't exceed some reasonble value (between 10-50 m/s?). Remember; you're aiming for maximum impulse, not for a high-speed jet. The remaining mass of the asteroid will receive the same impulse in the opposite direction.
If it has an effect it might disperse it a bit but garvity might still keep it together
The escape velocity of any small asteroid is minimal. You could jump with just your legs off of a 20km body and get lost in space just fine.
Re:how short is the notice? (Score:4, Insightful)
What about when it's the size of a small city?
I believe the official Protocol involves bending over and kissing your ass goodbye
Re:how short is the notice? (Score:4, Insightful)
Once again, this is for a short-notice event. Landing is hard, it takes a lot of energy. Crashing is easy, sometimes it happens when you're trying to land. Better to plan to crash.
Re:how short is the notice? (Score:2, Insightful)
While we're using made-up science far beyond the realm of our technology, why not just open a warp tunnel near the asteroid and teleport the thing somewhere safer?