Can We Shoot Nuclear Missiles Into Space?

Factual Questions
1

I watched the first half of an execrable NBC miniseries Meteor. The premise is that a giant asteroid is headed towards Earth, and the president authorizes shooting nuclear missiles into space to neutralize it.

Is this possible with our current missiles, or would we need to go back and retrofit them all before we launched them? Are their guidance systems precise enough that we could hit a target a few kilometers in diameter?

BONUS QUESTION: Assuming the missiles can be launched toward a target in space, is this a viable means of neutralizing Earthbound asteroids & comets? Is there a downside (beyond, of course, the fact that they might miss).

BONUS BONUS QUESTION: How many nuclear missiles does the US have?

2

[General Gray]
And risk turning one dangerous falling object into many?
[/General Gray]

From the documentary film Independence Day.

3

Or also, from a documentary on space exploration:

Cmdr Riker: Can we just blow it into pieces?
Lt. Cmdr Data: The total mass would remain the same, and smaller pieces would spread destruction over an even wider area. How the fuck did you graduate from the academy, anyway, numbnuts?
Capt. Picard: Lulz!

I may be slightly misremembering it.

4

Nope.

Current ICBMs are only made to just get them into space, orbit a little bit then fall back to earth on their target.

They are in no way capable of establishing a permanent orbit much less get away from the earth completely to go hit some distant target.

As to it being worth shooting incoming meteors with nukes it really depends on the size of the meteor. Nukes in space are not as effective as they are in an atmosphere. It’s ability to vaporize or deflect the rock would depend on several variables.

5

But a kick-ass Aerosmith soundtrack wouldn’t hurt, am I right?

6

I would suspect it’s easier to put a warhead on a space rocket (I’m picturing a lot of duct tape) then it would be to repurpose a ICBM to go into a non-ballistic trajectory.

But hopefully Stranger on a Train will come by and give us a more informed guess.

7

An ICBM just does not have enough oomph to get it out of earth’s gravity well such that it could keep going and hit a meteor (or whatever) far out in space.

This should not be surprising. ICBM’s were made to travel no further than roughly half way around the earth (if that far) to hit earth bound targets. They were never made to shoot things in space. To do so would have made them considerably more expensive to build and store.

8

And yet somehow Titan II ICBMs managed to put a bunch of Gemini capsules into orbit. Then again, not sure of the weight difference between a Gemini capsule and a warhead.

Anyhow, I think there is a treaty on the books that says we can’t put nuclear weapons “into orbit” so this isn’t a job anyone has engineered a solution for.

And furthermore, putting a warhead into orbit is probaby doable, getting it up to escape velocity to target said incoming METEOR might be quite another thing…

9

Space rockets are repurposed ICBMs.

10

The US currently has 738 missiles including submarine launched ICBMs. These missile carry somewhere around 1,950 warheads (MIRVs). (cite)

11

OK, this is a hijack, and I apologize in advance for it, but I just have to vent at some of the events in that movie that had me screaming at the screen. Note that I am not an astronomer, and my well be totally incorrect at some or all of the things in the movie that I am venting at.

(Also note that the following all occurred within the first ten minutes of the movie.)

Major Spoiler alert!!! If you have not yet seen this movie and intend to watch it, stop reading now.

The movie begins with an astronomer looking through the eyepiece of a huge telescope (not at any photographic plates or images generated by it) while frantically writing down notes. He then rushes to a laptop and starts enterinng data into it, presumably from those notes. (Question to astronomers: do you ever look through an eyepiece while running your telescopes, other than perhaps to initially align it?)

The scientist determines from the results that an asteroid of planet-killer size has been hit by a comet and is about to strike the Earth WITHIN 24 HOURS. Nobody else has noticed this.

So the scientist frantically calls the head of JPL at his home (this is in the middle of the night, and the head of JPL is in bed). He is unable to convince the head of JPL that this is important, and the head of JPL tells him to call him back in the office in the morning.

The scientist never sends any emails or makes any phone calls to anyone at the presumably hundreds of other telescopes who might be able to confirm his observations. He also does not email his critical data to JPL or anywhere else. This is far too important and urgent! Instead, he and his assistant jump in their car and start driving from their current location in Mexico to JPL labs to prove to the head of JPL that a planet-destroying event is about to happen WITHIN 24 HOURS. They bring along their laptop, which is the only place where the critical data about the event (which JPL desperately needs in order to intercept the asteroid) is stored.

Within hours the head of JPL labs is called to a secret base where he is informed that some sort of catastrophic event is happening (small meteors, remnants of the collision, are already hitting the Earth). He frantically tries to call he scientist’s cell phone, but of course the scientist and his assistant are driving through a “bad cell phone coverage” area and can’t talk to him.

This is a problem, because apparently nobody else can tell what’s happening here. Apparently the other telescopes can detect that there’s a major problem, but not where the asteroid is or where it’s heading. AND NOW THERE’S LESS THAN EIGHTEEN HOURS BEFORE IT"S GOING TO STIKE THE PLANET AND KILL US ALL!!!

(OK, it gets worse from here, but this is enough for my purposes. I feel better now.)

12

Not literally. Most “space rockets” used today are designed from the ground up to be space launch vehicles. (Though the Russian R-7 series, still used to launch Soyuz and Progress capsules, is a notable exception.)

Anyway, if we needed to put a warhead into an escape orbit, you want to requisition a rocket that’s being prepared for launching a geostationary orbit or an interplanetary probe. Ideally you want to take a probe (which would already be equipped for long-distance communication and orbital corrections), remove the scientific instruments and fit a warhead on it.

As for the asteroid, you don’t want to destroy it, you want to nudge it away. A nuclear warhead going off near the asteroid should work pretty well - it would vaporize some material on that side of the asteroid, which acts as a rocket and push the asteroid. It needs to be done well before it approaches earth, of course - months if not years before the predicted impact.

13

Not professionally, at least. Many professionals are also amateur astronomers, and enjoy sticking our eyeball against a lens in our free time, but that’s probably going to be something man-portable in the backyard, not the big research scope.

This’d be a lot more plausible without the comet. There have actually been cases of disturbingly large objects passing disturbingly close to Earth and not being noticed until they were actually past, and it’s not entirely impossible that an extinction-sized object might escape notice that long. Comets, though, by the time they get anywhere near Earth have a huge, bright coma that would surely have been noticed long before.

There’s also the issue that you can’t determine an object’s orbit from a single observation (if all you have from each image is position on the sky, you need at least three images from different times), but we’ll gloss over that for the sake of the story.

There are systems in place to disseminate astronomical breaking news like this quickly across the world. It used to be done via telegraph, but now it’s all e-mail. Realistically, he would have sent the e-mail before he made the phone call, and the director of JPL (and every other astronomer in the world) darned well would get out of bed for this.

14

I’ve long wondered about this. If I can break the incoming object up into many smaller pieces, each will enter the atmosphere separately, fewer will reach the ground, and each will cause a less massive explosion - compare throwing a rock with a fist-full of gravel. Get the pieces sufficiently small and there’ll be minimal damage - compare throwing a rock with a fist-full of sand.

15

Depends how small you get them.

Not sure 4 1-mile wide rocks is an improvement over 1 4-mile wide rock.

Might be…dunno. Either way it’s gonna suck.

16

Or, perhaps even more tellingly, you can compare throwing a boulder with a fist-full of dirt. :wink:

17

And yet the total kinetic energy of the fragments remains about the same. Now, though, all of that energy is being dumped into the atmosphere, instead of some of it being spent to fling enormous quantities of debris into space. With the massive amount of energy carried by an extinction-level object, the result is that global air temperatures jump several hundred degrees Celsius and everybody dies.

18

Re the “can we shoot them into space” question, the answer is “not hot out of the silo”, but I strongly suspect that existing boosters could be strapped together or otherwise modified to permit it if the stakes were this high.

Regarding whether to shoot to deflect or to smash, deflection might be more elegant, but in a pinch I’m with Quartz. While the net mass of multiple fragments might remain the same, there’d be more net surface area, letting the atmosphere do a better job at resisting/deflecting them. Also, in a life-of-the-planet-or-death scenario, we wouldn’t earn extra credit for the economy of our solution. I would hope that in an eleventh-hour defense against an incoming rock, we’d plan on going out Scarface Style – “Say hello to our little friends!” – with as many cobbled together boosters and bombs as we could possibly muster. Break a 4 mile rock into 4 one mile rocks… Then smash each of those and everything that’s left. It’s not like there’s some kind of global nuclear warhead shortage.

19

Nitpick: if you break up a 4-mile wide rock into 1-mile wide rocks, you end up with about 64 pieces, not 4.

And I’m pretty sure that is not an improvement. Even a 50-meter (160 ft) diameter rock can make a pretty impressive crater.

20

Nit-nitpick: what if it was 4-miles wide, but only 1 mile high and 1 mile deep?! Huh? huh?