# Russian boffins want to nuke asteroids

Russian space scientists want to deploy nukes against killer asteroids. Russia and India Report quotes Tomsk State University scientist Tatyana Galushina explaining modelling led by the university to find out how best to blow up a dangerous asteroid. Galushina reckons a near-Earth rock that poses a future threat could be …

1. #### Treaties schmeaties

It's currently illegal to fire off nukes into space, however, and The Register can't imagine the world's powers changing non-proliferation treaties in a hurry.

If a 300-meter class asteroid is predicted to hit in the next 10 years, they will. In fact, I am pretty sure the big boys will try to nuke it regardless of what non-proliferation treaties say.

1. #### Re: Treaties schmeaties

It would be much easier and reliable to deliver and fire rocket boosters to change trajectory.

1. #### Rocket boosters for asteroid deflection

It would be much easier and reliable to deliver and fire rocket boosters to change trajectory.

Possibly, but the math does not quite work out with chemical engines and contemporary technology.

Assuming that the Wikipedia's estimate of 3.5/t × 1e−2 m/s required delta-V is correct, and taking t=10 years, one would need 3.5e-3 m/s deflection. For an asteroid of 4e10 kg mass, one would need to expell:

4e10 [kg] * 3.5e-4 [m/s] / 3e3 [m/s] = 4.7e3 [kg]

kilograms of reaction mass at 3 km/s velocity (assuming a solid monopropellant). Waiting until it's only 2 years before the impact (which would be the human nature to do), will increase the delta-V and propellant requirements by a factor of 5.

I am sure delivering this propellant and supporting hardware to an asteroid in solar orbit would be well within Bruce Willis' capabilities, but probably nobody else's at the moment.

It should work out with solar- or nuclear-powered ion thruster engines, but it is always nice to have a plan B (ie the nuke) ready.

1. #### Re: Rocket boosters for asteroid deflection

@anon coward

So it's merely 112619.0476 Kilojubs to be delivered by 156908 Norris's and that will achieve the desired outcome of 66.7111% of the velocity of a sheep in a vacuum on that so called treat to humanity.

Bruce Willis can sty in bed mate..he's a pussy anyhow.

cheers

1. #### Re: Rocket boosters for asteroid deflection

@AC - That's for incomings...it's all considerably cheaper when you're talking about outgoings. Thinking about it, you could probably change the trajectory enough by sticking a mirror in the right place. That's not as much fun as nukes though.

1. #### Re: Rocket boosters for asteroid deflection

"Thinking about it, you could probably change the trajectory enough by sticking a mirror in the right place." or painting half of it white.

2. #### Re: Rocket boosters for asteroid deflection

I'm reading this on my phone in a queue, but just thought I'd say that, er, ACs maths look sound to me.

Indeed, there's some good numbers and letters there.... there's 4e10.... oh look, 3.5e.... carry the 1... Yup, I agree. Well done.

Carry on

1. #### Re: Rocket boosters for asteroid deflection

How many Kerbals do we need?

2. #### Re: Treaties schmeaties

Problem is you've then got radioactive meteor fragments covering the planet. That's why they made the point that they were doing this on asteroids which came close but didn't quite hit as they left, so that when they circle back they won't be a threat

1. #### Re: Treaties schmeaties

Problem is you've then got radioactive meteor fragments covering the planet.

The proposed deflection missions generally occur years in advance of impact. Common elements (carbon, silicon, oxygen: the stuff of rocks, soil, and asteroids) irradiated by a nuclear weapon's detonation to produce fallout or radioactive asteroids have half-lives in terms of days and weeks. A ground burst crater may be crossed by infantry in NBC suits within 2 weeks. In a year's time, it'd be safe for tourists, like the Trinity test site.

In short, by the time a nuclear-dispersed cloud of asteroid fragments reaches Earth, it won't be radioactive except for a few kilograms of lingering bomb bits.

Now, if the asteroid disassembly happens within weeks of impact, sure, you've got some fallout to deal with. On the other hand, Earth has lived through hundreds of megatons of fallout from above ground testing while a solid asteroid is a more significant hazard.

3. #### Yah, but the real, actual and operative impediment to nuking an asteroid

Is that it justifies the stockpiling of ICBM's and their payloads during the Cold War. That Comintern directed pacifist Nuclear Disarmament carnival from the 50's and 60's is suddenly made to look like a lemming suicide mission. Can you imagine the jaw grinding when the headline, "Planet Earth Saved by Giga Ton H-bomb Originally Targeting Washington DC" hits the web waves? It would be a pan national St. Vitus Dance mosh pit and worth an investment in popcorn futures.

4. #### Re: Treaties schmeaties

"It's currently illegal to fire off nukes into space"

Since when did Russia start caring about international law?

1. #### Re: Treaties schmeaties

@AC or the USA, come to that.Them buggers in Westminster aren't all that keen on it either, unless it suits their purposes.

2. #### changing non-proliferation treaties in a hurry.

That is exactly how they are going to change them when we get a forecast of an asteroid hitting the Eastern seaboard.

1. #### Re: changing non-proliferation treaties in a hurry.

I assume you mean of the US and infer that no-one will care if the asteroid hits their Pacific coast?

1. #### Re: changing non-proliferation treaties in a hurry.

Or ours. Blackpool wouldn't be a great loss now would it?

1. #### Re: changing non-proliferation treaties in a hurry.

Blackpool, Glasgow, Liverpool, Wales ...

1. #### Re: changing non-proliferation treaties in a hurry.

Save the Wales!

1. #### Re: changing non-proliferation treaties in a hurry.

Nuke the Wales!

3. #### See you next time around!

Surely some of the (now radioactive) detritus would stay on the same relative path.

1. #### Re: See you next time around!

Given the megatonnage of surface-based nukes we've detonated just to tweak each other nose in the past 70 years, somehow I do not think another 1, 10, or 100 megatonnes to save everybody's ass is going to matter much.

2. #### Re: See you next time around!

Surely some of the (now radioactive) detritus would stay on the same relative path

So?

If that detritus is now small enough to burn up in the upper atmosphere then it'll be a small radiation dose deposited globally, small in comparison to the results of atmospheric H-bomb testing (which we did in the past, and survived with few casualties). If it still reaches the ground the radioactivity will likely be far less of a disaster than the consequences of megatonnes (or gigatonnes) of kinetic energy, which in turn will be a fraction of the original disaster if we had not used the nuke.

Of course, if we started planning now to get a nuclear-powered ion-drive tug on standby in orbit, we would not have to resort to desperate measures at some unknown time in the future. It would not be a significant radioactive re-entry hazard until its core had been powered up for some time, at which point it would no longer be in earth orbit. If virgin enriched uranium fuel got vaporised in a launch accident and/or lost in the ocean, that would not be any sort of radiological disaster.

запуск!

1. #### Re: Mihail, change the status to "Brown Trouser Time"

For future reference, brown trousers time in Russian is "Медвежья болезнь".

That translates as "Bear sickness". Apparently, when the sh*** hits the fan, a brown bear will empty its bowels (same as quite a few other animals and birds) to ensure it does not carry any extra weight when it needs to leg it.

1. #### Re: Mihail, change the status to "Brown Trouser Time"

Honestly, I am sometimes stunned at the sheer breadth of knowledge I pick up here. I'm not sure in what context I'll ever use this one, but thanks nevertheless :).

2. #### Re: Mihail, change the status to "Brown Trouser Time"

Sure that's the derivation? It's the same instinctive reaction, but I'd have thought that the "sickness" related more to the human who is legging it with a bear in angry pursuit!

2. #### Re: Mihail, change the status to "Brown Trouser Time"

> запуск!

It's "пуск!", but перегрузка is real.

1. #### Re: Mihail, change the status to "Brown Trouser Time"

Wait, I'm lost here. So a brown bear shits itself when it's about to get hit by a nuke?

5. #### One small problem....

Galushina reckons a near-Earth rock that poses a future threat could be smithereened by a nuclear weapon when it's moving away from us.

If it's moving away from us.. it missed. So it wouldn't be a "killer asteroid". Methinks someone just wants to get nukes in space.

1. #### Re: One small problem....

Hello, "future threat", yes? That is, we have already seen this asteroid aforehand, it's passed by this time, but its future path has been well-characterised enough that we can tell that N+1 or N+m orbits from now that it and the earth will definitely intersect.

So no use for the new guy on the block introducing themselves with a "mind if I barge in?", but useful for something we've gotten a whiff of and don't want plopping onto our couch.

But for all that, making sure that whatever much smaller pieces still will intersect with earth have been christened with eau-de-Pu doesn't thrill me.

As someone else here suggests, send a thruster up and shove the whole thing into a safe orbit. That is applicable for many more cases, such as asteroids that haven't yet passed by cuz they're gonna hit first time up at bat. Go for the more general case rather than the special case mooted here, okay?

2. #### Re: One small problem....

Methinks needs to read for content and enter a 2+2=4 space.

3. #### Re: One small problem....

"If it's moving away from us.. it missed"

...This time

It'll be back.

4. #### Re: One small problem....

"Methinks someone just wants to get nukes in space."

What is clearly needed is more sharks with lasers. ...in spaaaace!

6. I thought everyone understood that nuking asteroids only works in movies...? Even then, it doesn't seem to work so well, if memory serves.

1. #### Movie nukes

Just make sure to pack the manual detonator cord. Because that's normal to design for a nuke.

7. #### I thought nukes were not a solution ?

We've already had this discussion, and it was said at the time that most of a nukes' force in space is dissipated via radiation because there is no atmosphere to push around. It is our atmosphere that gives a nuke it's deadly, destructive power.

Even the slop trap Armageddon made the misfits drill into the asteroid in order to explain why the nuke would work.

I am therefor sceptical when reading that shooting off a few nukes to have them blow up on a large asteroid's surface would "turn most of the asteroid into liquid and gas". What have they changed in their simulations to get this result ? Or is this the result of our newfound knowledge on asteroids in general ?

1. #### Re: I thought nukes were not a solution ?

Venturing a guess - using a penetrator, instead of a proximity or surface burst. This is feasible for "leaving" rocks - for "incoming" rocks the delta-v for a penetrator to be feasible is off the scale.

If you use a penetrator, the adjacent rock is instantly vaporized providing the necessary impactor so that the energy is not wasted.

There are some tech issues with that though:

1. You need to get the speed just right. So you need a lot of more fuel to drop the delta-v down so that the nuke does not disintegrate on impact.

2. In an ideal world, you will also need a pilot probe(s) to impact the asteroid before the nuke so that you identify it correctly as rock, ice, whatever and get the delta-v down to the correct value for the penetrator reaching optimal depth

3. For a half a ton to a ton worth of nuke (assuming a 10Mt warhead) you now need several tons of armor to form the penetrator and ensure that the nuke arrives to the spec-ed depth intact. That, once again, means a boatload of fuel.

4. It definitely works only on "leaving" rocks as suggested by these guys. An incoming rock has delta-v in the 10s of km/s. We do not possess the technology to reach it in time, drop the speed to a point where the penetrator will not disintegrate and perform an attack run.

1. #### Re: I thought nukes were not a solution ?

I'll try and remember all that the next next a client rings me up with an asteroid problem.

In the past I've always used to probe that comes with preparation H on them.

2. #### Re: I thought nukes were not a solution ?

Even the slop trap Armageddon made the misfits drill into the asteroid in order to explain why the nuke would work. ... I am therefor sceptical when reading that shooting off a few nukes to have them blow up on a large asteroid's surface would "turn most of the asteroid into liquid and gas".

Armageddon was dealing with an asteroid the size of Texas (i.e., bigger than Ceres) with 18 days before impact. Such large bodies would be gravitationally consolidated and would have survived numerous megaton-level impacts in the past. Substantial handwavium boosted with large quantities of unobtainium were required to destroy the asteroid in time for the so-called love story side plot to reach its Hollywood ending.

Meanwhile, the proposed target asteroids (200-300m) by this paper are about the volume of the crater excavated by Operation Plowshare's 104-kiloton Sedan shot but the proposed demolition charges are 1 megaton. You have an excess of energy to overcome disadvantages like inefficient energy transfer.

However, I'd note that nuclear disassembly of asteroids does not require high speed interception and proximity detonation. You're probably making the interception years ahead of time so the weapon can make a soft touch down (presumably carried by a derivative of some other asteroid probe, like Rosetta). A weapon detonated on the surface of an asteroid will pump about half its energy into the asteroid's surface because the asteroid occludes about half the visible sky, more if you find a nice crater to settle in.

Asteroid material isn't air, but when heated to several bajillion degrees by half the energy release of the demolition charge it will act quite like a fireball and move some mud. See: Sedan shot. Bonus: you get a rocket-like effect from the surface because the obvious expansion path between the massive, disintegrating bulk of the asteroid and empty space is into space. You destroy and deflect.

8. #### Just one thing

If we nuke an asteroid and it breaks up, the bits that have broken up could continue heading towards the Earth. All these bits would surely contain radioactive material.

Now I'm no scientist, but wouldn't the material entering the atmosphere, even if it were burnt up, still be radioactive? So we'd have avoided a holocaust involving an asteroid, but would instead inflict a nuclear holocaust on ourselves instead?

1. You missed the part where it is stated that the nuking would happen after the body passes Earth - therefor sending the pieces every which way toward Mars and Mercury.

So Earth escapes intact - but this plan does not bode well for future Martian colonists.

1. Mars does not bode well for future Martian colonists. They'll have enough problems to overcome that a scattering of (by then) mildly irradiated gravel will be the least of their worries.

2. #### Re: Just one thing

As previously noted upthread, we've set of plenty of nukes inside our atmosphere, a few bits of rock that have had at least a year (assuming it's in a similar orbit to the Earth) to 'cool off' won't be too much of a bother.

9. #### I have an issue with this concept ...

"Galushina reckons a near-Earth rock that poses a future threat could be smithereened by a nuclear weapon when it's moving away from us."

So instead of taking on a cannon ball, the Earth takes on (potentially radioactive) grape shot? You are not going to change orbital mechanics with a nuke, no matter how you squint at it.

1. #### Re: I have an issue with this concept ...

the Earth takes on (potentially radioactive) grape shot?

That is preferable! Because most of the smaller pieces will burn up in the atmosphere without hitting the ground, and the rest do not cause as much destruction as a hit by the the whole cannon ball would have. As for radioactivity, some of it will have dispersed widely in the explosion, and during the round-trip the asteroid makes before the fragments hit us, so we don't get all of it. Some of the short-lived isotopes will also have decayed. Besides, we survived the 1950's bomb tests, which spread much more radioactive dirt around.

10. #### Nuking the asteroid when it's moving away from us

...there wouldn't be a risk of radioactive debris entering our atmosphere

That is, not until its radioactive debris comes around in a couple of years time. At least, probably by then we, or rather the monkeys who will have taken over by then, won't get the very highly radioactive stuff. Or maybe it will be the cause why other apes are going to take over?

11. How about a lander carrying both an ion thruster (or similar) and a nuke?

First tweak the trajectory a bit, then blow the thing up, to increase the chances that neither the asteroid nor its debris won't hit Earth. Ideally the debris would end up either in the sun or outside the solar system for good, but I guess that is a bit too much to ask for.

12. #### Nukes in SPAAAAACE

You are all like totally overanalysing this.

1. #### Re: Nukes in SPAAAAACE

Yeah, but what else are you going to do on a Tuesday morning? Work?

13. #### Practical Propositions?

I see why we'll need a back-up for emergencies. Hopefully it will never have to be used.

It is not known how many of these near Earth impactors do or will exist - the 'emergencies' may persist and this will multiply the future return of radioactive detritus.

The balance of the Solar System will be altered anyway so one might as well try for attachable impellors to change the asteroids' trajectories and yet it would seem more feasible to capture them as gifts of outside orbit matter, propellant etc. for our expanding explorations.

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