Nukes Against Earth-Impacting Asteroids

TopSpin writes "Flight International reports that scientists at the Marshall Space Flight Center have developed designs for an array of asteroid interceptors wielding 1.2-megaton B83 nuclear warheads. The hypothetical mission for these designs is based on an Apophis-sized Earth impactor 2 to 5 years out. According to NASA, 'Nuclear standoff explosions are assessed to be 10-100 times more effective [at deflection] than the non-nuclear alternatives analyzed in this study." On April 13, 2029, Apophis will pass closer to earth than geosynchronous satellites orbit.

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[thibbledorf]

edit: Would an explosion in space even function in the same manner?

Re:this is not armageddon NASA :)

[Reaperducer]

The more porous asteroids don't seem to respond as well to such explosions.

You say this based on... what? Exactly how many nuclear weapons has NASA detonated in space while I was asleep?

Re:this is not armageddon NASA :)

[AKAImBatman]

you just made a single asteroid into a hail of dangerous shrapnel.

Shrapnel == Greater Cross Section
Greater Cross Section == Atmosphere has greater effect on projectile
Atmosphere has greater effect on projectile == Energy dissapated over wider area
Energy dissapated over wider area == No boom today. Boom tomorrow. Always boom tomorrow.

Re:FUD alert..

[QuantumG]

Apophis is a perfect example of how flawed the current system for identifying potentially hazardous near-earth asteroids is. A two body analysis showed that it was on a collision course, but a more intensive three body analysis showed it would miss by a lot. Thing is, the opposite could potentially also be true - a two body analysis might show that an object is not a threat when, in fact, it is and a more heavy analysis would show that. We need more resources dedicated to this very real threat to our planet. Only with early detection do we have any chance of deflecting a planet killer.

What about other options?

[Nyeerrmm]

They claim 10-100 times more effective than other methods. First of all they dont define more effective. Second of all, they seem to dismiss ideas like a gravity tug out of hand as not developed enough.

The idea of throwing nukes at an object of potentially unknown size bugs me, especially when much more controlled options exist. All that needs to be done is to nudge the NEO out of small zones known as "keyholes" that are small, finite portions of space where the pull of the Earth will push the object into a collision course on its next orbit rather than another random non-intersecting orbit.

A fairly massive object (something a Delta IV Heavy could launch) would be perfectly capable of handling an Apophis sized object with enough lead time (on the order of years, but certainly less than decades), by flying in formation with the object in the right location to shift its orbit slightly. This is a lot easier than Apollo, which we pulled off in less than 10 years, so to dismiss it as too difficult is ridiculous, and it seems a lot more responsible than launching nukes at an object we dont fully understand.

Just my thoughts anyway.

Why don't we capture it

[EEPROMS]

Instead of destroying what will be a huge supply of mass and resources why dont we put it into orbit between the moon and earth. One of the major issues with space exploration is "mass and fuel" as it costs a fortune to put it into space. I think we are wasting a huge opportunity here to accelerate space exploration while making it 1,000 times more cost effective.

Re:nukes overhead

[Muhammar]

Nuke explosion high in the orbit was tested as a radiation shield in antibalistic missile experiments (Operation Argus, by Nick Christofilos of Lawrence Livermore fame) and it was found ineffective for the defense purpose. A side-product of these experiments with artificial radiation shields was discovery of Van Allen radiation belts.

It was later found by accident that multimegatonn explosion high in the orbit can dump lots of charged particles (mostly high-energy electrons) into Van Allen belts where they persist for many weeks during which time they gradually degrade solar panels and electronics of satelites - this happened in 60s (after operation Starfish Prime about 5 satelites went silent...)

Re:Star Wars Fakeout

[wall0159]

I think the words you want to use are "expected outcome," which allows you to conclude that a somewhat unlikely disaster is worth avoiding more than a possible problem. Your rebuttal to Doc Ruby is correct, however (as I've said in a sibling post) why is the government ignoring global warming? - according to scientific consensus this is much more probable than a meteorite impact, and could be nearly as devastating.

I'm not saying we shouldn't worry about asteroids, but rather that this suggests that the government may have some other motive for funding such research.

Re:oh noez!

[rtb61]

Almost correct. There is also the superheated high velocity remnants of the nuclear weapon casing and delivery mechanism at the leading edge of the shock wave, oddly enough more significant in space than it is in a planetary atmosphere, missile should rotate and detonate butt first.

Re:Why don't we capture it

[evanbd]

You're thinking about distance in space all wrong. For purposes of impact likelihood, how many kilometers away it is going to be matters. For ease of getting it into orbit, it's close to irrelevant. Given time, moving things long distances in space is easy. You just have to do it slowly. So an asteroid that is very far away (relative to impact distances) at closest approach is not necessarily hard to move. What *is* hard is changing something's *velocity*. That takes propellant (or a long time with a solar sail or whatever -- regardless, it's hard). Apophis has over 5 km/s of "hyperbolic excess velocity" -- ie the speed it would be moving when it got here ignoring Earth's gravity. To bring it into orbit, you have to apply that much delta-v and then some -- so around 6-7 km/s (sorry, not going to do the math in detail right now). In contrast, there are plenty of near Earth asteroids that don't present an impact risk, but have well under 1 km/s of hyperbolic excess velocity. That makes them around 6x easier to bring into orbit per unit mass (or more, if you're stuck with relatively crude propulsion systems).

But why Ares V as launch vehicle?

[XNormal]

I would feel much more comfortable with a planetary defense system that does not rely on a single, unbuilt launch vehicle.

Instead of carrying six weapons on a single platform it would be better to have smaller vehicles that can be launched on Atlas, Delta, Ariane, SpaceX falcon, etc.

Re:Star Wars Fakeout

[dave420]

Exactly. Even if a superpower, or even suitably-armed power, wanted to launch a nuclear strike against the US, a sea-launched nuke-carrying cruise missile would do the trick. Flying low and fast, space-based anything won't help. And if that's out of the budgetary question, a container with a nuke in it would be just as acceptable. Taking out just one large US port will harm the US in so many different ways it's not even funny.

A good use for enhanced radiation devices

[rben]

I read a novel, I can't remember which, where the author made a great case for using enhanced radiation weapons against asteroids instead of conventional nuclear devices. His argument was that a non-impacting explosion using an enhanced radiation device might be able to divert even a fragile asteroid without necessarily breaking it up. The radiation from the weapon would transfer it's energy evenly to the surface of the asteroid. (Not exactly, but way better than a regular nuke) That would blow away the top layer of the asteroid on the side facing the blast, pushing the asteroid in the opposite direction. A series of such blasts might be able to divert the asteroid without causing it to break up.

I'm sure there are problems with the idea, but it seems logical to me.

Re:S.T.U.P.I.D.

[master_p]

If you simply wanted to stop the Japanese, why didn't you simply drop the bomb on Fujiyama (for example)? I think that the sight of a giant volcano being blown to smithereens would have been just as effective as dropping the bomb on Hiroshima and Nagasaki.

The sad truth is you wanted to test the bomb as well as show to the Soviet Union that you have some big guns.

Re:S.T.U.P.I.D.

[professionalfurryele]

There is considerable debate on this issue as far as I know. Militarily the Soviet Union posed far more of a threat to the short and long term security of the civilians of Japan (it's not like what happened to Berlin was a secret, or what would happen to eastern Europe wasn't known). There is however one thing that is clear. The atomic bomb gave Emporer Hirohito (and to some extent Togo) the excuse he was looking for the push for an end to the war on all fronts. Civilians would understand surrender faced with this new terrifying weapon. The coup attempt that resulted from the repeated attempts to surrender was probably far smaller than it would have been without the bomb. The terms of the surrender were sufficient for the allies. The last one is the key. Without the bomb, would the Japanese have accepted unconditional surrender (with the exception of the retention of the Emporer) if the allies did not have the bomb? Maybe, but we know four of the big six wanted to reject the Potsdam declaration out of hand until the extent of the Soviet attacks became known, and the attack on Hiroshima and Nagasaki. Then it was split 3-3. Without the intervention of Emporer Hirohito (who certainly considered the bomb important) this deadlock may have lasted.
I don't know what the result would have been without the bomb. Perhaps the Japanese would have continued fighting until it was clear that the Soviets were preparing to invade Korea, or perhaps the Japanese islands themselves. It is possible that without the bomb the Japanese would have used losing territory to the Soviet Union as a bargaining chip against the Americans to get more favourable terms.
Your point about American B-17 raids on Japan is a good one. It is important to remember these were small nukes. The building directly under the bomb survived the explosion in Hiroshima. This does strongly suggest that the bomb was not, in the military leaderships mind, a deciding factor, considering that the death toll in Tokyo from fire bombing was higher than in Hiroshim or Nagasaki through the atomic bomb. However, the bomb is more than a incendiary weapon. I believe the Emporer said it best in his radio address to the Japanese people:
"The enemy now possesses a new and terrible weapon with the power to destroy many innocent lives and do incalculable damage."
The key word being terrible. The atomic bomb, more so than any other weapon, was terrifying. It is this terror that gave the Emporer the option of offering surrender (along with the Soviet invasion).

Re:S.T.U.P.I.D.

[professionalfurryele]

I'm not American, I'm British. And I agree with most of what you have said. The American military reasoning for dropping the bomb was reprehensible. Doesn't change the fact that the 'excuse' they gave for doing so holds water.
I'm well aware that the total deaths from dropping the bombs total around a quarter of a million. I also had in my mind the bombing of Dresden and Tokyo. However, the fact remains that if Imperial Japan had been allowed to survive that number would be a drop in the ocean, because you can bet your arse that the Soviet Union would have found an excuse to restart the war at a later date if Japan didn't essentially become a satellite state of the United States.
A demonstration would not suffice. For a start it would tell the Japanese that the Americans had the bomb. The Japanese were not intercepting lone bombers at this stage because of a lack of fuel. If they know that they were carring the atom bomb that might have changed that. Besides, a demonstration would appear weak, like the Americans were unwilling to use the bomb.
I believe the US military has been responsible for many immoral acts. The Vietnam war immediately springs to mind. The premature invasion of Iraq in the second gulf war. The premature exit from the first gulf war without forcing unconditional surrender, leaving thousands of Shiite insurgents to die in a rebellion the Americans encouraged.
It is not a question of inability to admit the failing of my own (or in fact your country), but rather my capacity to way evidence without becoming overwhelmed by the horror of the facts.
What purely military base should they have targetted? You know of a naval base not inside a city?
Osama bin Laden is not leader of a sovereign state. Nor was the intent of the 9/11 attacks to target military infrastructure in the case of the World Trade Center. Nor did the people delivering the attacks wear a uniform marking them as combatants. There was no declaration of war (at least in part because you have to be a sovereign state to declare war). If the West was at war with Saudi Arabia and they fire bombed Washington to get to the pentagon, that would be a fairer comparison.
The actually reasons for using the bomb are morally reprehensible, but the excuses given hold. All I am saying is you put me in Harry S. Truman's shoes and give me the two choices he was faced with, I would in good conscience make the same decision he did.

Re:S.T.U.P.I.D.

[professionalfurryele]

I've addressed every point you have made else where. I have already conceded that the reason the Administration had for dropping the bomb was morally reprehensible. However all of the quotes you have given talk of surrender, not unconditional surrender. If you do not believe that a power which has committed copious war crimes and conducted a war in a manner so morally reprehensible as to deserve the title infamous, should be deconstructed, that is your choice.
I will answer some of the quotes you present. Eisenhower was mostly involved in Europe. His pacific counterparts did not agree with his assessment and I choose to believe them because they would know better.
Suing for peace != unconditional surrender. I've already acknowledge that militarily the atom bomb did not determine the outcome of the war. Heck the outcome of the war was known after Midway.
Surrender != unconditional surrender.
Dropping the atom bomb to force unconditional surrender is not the same as dropping the bomb as a last ditch spiteful move to kill civilians. A better comparison might be, what if the Germans had the bomb in 1941 and destroyed Scapa Flo?

Freeman Dyson's View

[systemeng]

When I was getting my degree at Harvey Mudd College, they managed to get us the opportunity to have lunch with distinguished Physicist Freeman Dyson. Someone asked Dyson a question about blowing up asteroids with nuclear weapons at the session. My recollection of the response was that he said he thought it was a bad idea that would make shrapnel and magnify the problem. Dyson told us that the best solution he could think of was to build a ship to go to the asteroid and then assemble a "mass driver". The mass driver would be a piece of equipment that broke off pieces of the asteroid and hurled them at right angles to the trajectory in an appropriate direction in order to divert the orbit. While Dyson is only one man, I suspect that his opinion on the matter might incorporate more finesse that a bunch of weapons engineers.