Nukes Not the Best Way To Stop Asteroids, Says Apollo Astronaut

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."

Comments

Alternative sugestion

[Anonymous Coward]

Move it into orbit and mine it.

The interesting bit...

[pagewalker]

He's saying pushing or pulling an asteroid is better than hitting it with a nuclear weapon, but the interesting thing is that he's claiming NASA issued its pro-nuclear statement last year in response to political pressure to put nuclear weapons in space.

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Re:The interesting bit...

[Oktober Sunset]

Ahhh, an ICBM works just fine at getting the nuke to it's target, but the target has a lot of warning, from when they see the launch, till the nukes hit is time to do a lot of things, including evacuating stuff, and sending retaliation, now if the nukes drop from orbit, straight down onto the poor fuckers head, their warning if they manage to spot a tiny re-entry module decending straight down at high speed, will be a very short amount of time indeed, thus meaning no time to prepare for impact or retaliate on as large a scale, fueling up lots of land based ICBMs despatching bombers, and evacuating major targets to preserve as much second strike capabilities as possible is all out. The enemy would be hit much harder, and thier retaliation would be much smaller. Consisting only of any ICBMs already fueled, and hidden capabilities on submarines.

A strike on a country like Pakistan or India from space could probably be done with no retaliation at all, thier liquid fueled rockets just wouldn't be able to launch in time. And it would tip the scales massively against china, as it had a lot of land based missiles but only 1 nuclear submarine carrying only 12 single warhead missiles (as opposed to the US whch has 1152 warheads in it's submarines). So there are lots of reasons why the US would want nukes in space.

Re:It depends on the timing...

[techno-vampire]

Not really. Let's say that the most we can do with a nuke is slow the asteroid down by 1 f/sec. Doesn't sound like much, does it? but if you do it 30 days before impact, that shifts the asteroid back almost 491 miles. If you have six months, it's over 2000 miles. Considering that the Earth is a moving target, that might be enough to ensure a miss. You're not trying to blow up the asteroid, you're just trying to nudge it into a slightly different orbit that doesn't impact the Earth, and if you have time, it doesn't take very much.

Re:It depends on the timing...

[Lillesvin]

Actually, I remember seeing some documentary on national Geographic (iirc), where they explored this exact topic.

The problems with nuking asteroids are (apparently) the inherent danger of radioactive fragments falling to earth and of course the fact that asteroids aren't actually solid --- they usually consist of a lot of small pieces of rock, hence making it hard to actually do anything to them with force. Of course, these weren't the only problems, but they're the ones I can remember. Might have been the same guy as the one from TFA pointing it out --- I'm not sure. Also, I'm a linguist, so my knowledge of astronomy and nukes is limited.

Hit asteroid with "slap" very repeatedly.

[dsmall]

Weapons effects are extremely interesting and useful. The first effect to know about is that stuff survives amazingly close to a nuclear explosion. The second effect is that you can "tune" a fission bomb to direct its energy output largely in one direction. (Don't jump on me, this is in the open literature now.) Which gives a different method of dealing with asteroids; a series of powerful, but not shattering, plasma "slaps" to change its orbit.

Send a spacecraft armed with lots of quite small fission weapons that are set up to direct their weapons effects mostly in one direction and with a very basic, robust guidance system. Each one needs to get tossed out, line up with the asteroid, trigger, and "slap" it with high-speed plasma. Enough "slaps" change its orbital characteristics. You don't try to shatter it.

Each fission weapon looks like this: Wrap up a small (5 kt?) fission core with something like polyethylene or anything that absorbs prompt soft X-rays. Anything that has mass. The onboard computer works with guidance (my guess would be aims for a laser point on the asteroid, but who knows), the guidance just lines it up properly with the asteroid, and triggers the fission.

Position it so that when it goes off, the plasma of the polyethylene (and the former physics package, etc), moving around 2.5 million miles per hour, strikes the asteroid. You don't try to break the asteroid up -- far from it. You go for a series of "slaps" with very hot material. As the physics formula says, Mass times Velocity Squared -- and here you have all kinds of velocity.

As Lew Allen proved, with his famous tests with steel spheres just a few feet from ground-zero of a nuclear test survive just fine, and they are accelerated quite briskly. This was one basis of Project Orion later on.

It would be quite interesting to model this against some asteroid sizes and get an idea of what would be required to change the trajectory. We certainly have enough plutonium cores laying around.

      Just an interesting thought.

      Thanks,

        Dave Small