Nukes Against Earth-Impacting Asteroids 491
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.
APOP-Whut? (Score:5, Informative)
Otherwise known as the personification of all that is evil.
Re:what if they miss hteir shot (Score:2, Informative)
FUD alert.. (Score:5, Informative)
this is not armageddon NASA :) (Score:3, Informative)
Re:Uh oh... (Score:3, Informative)
Re:what if they miss hteir shot (Score:5, Informative)
From the 40s up through I think the 70s many nuclear weapons where detonated in the atmosphere. While it was a really bad plan life pretty much kept on living. A miss would probably not hit the earth and a launch accident wouldn't cause a nuclear detonation. A common method of safeing a nuclear weapon involves filling the pit with a neutron absorbing wire. Once the weapon leaves the atmosphere a motor will pull the wire out of the core and only then the weapon will be capable of nuclear detonation. Not only that most modern weapons are much cleaner then the bombs of the 50s.
So I wouldn't to see them launching them daily I think risk to benefit ratio is pretty good.
Re:FUD alert.. (Score:5, Informative)
Re:oh noez! (Score:5, Informative)
Re:Yes (Score:2, Informative)
Think of it like a ceiling fan that goes back and forth. If it didn't have the ability to turn back on itself, it wouldn't do much to the air. However, if the blades bent in different directions for each direction, it would be able to produce a downdraft.
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Re:FUD alert.. (Score:1, Informative)
Re:Uh oh... (Score:5, Informative)
Re:Apophis should be able to be destroyed... (Score:1, Informative)
Re:oh noez! (Score:5, Informative)
The first destructive effect is caused by the radiated energy itself, but most of the destructive power of an atmospheric nuclear detonation comes from the quick heating and displacement of huge quantities of air that creates the explosive shock-wave.
In space, only the radiated energy of the detonation remains. While it would be sufficient to deflect an asteroid, a nuke is nowhere near as destructive in deep space than it is on Earth.
Re:nukes in the atmosphere (Score:4, Informative)
The radiation from the nuke isn't the problem with that. The main effects are (a) EMP and interfering with electrical equipment, and (b) fucking up the magnetosphere, and possibly reducing the Earth's shielding from cosmic radiation. Neither of which are good, but better to risk those effects than the certainty of a large asteroid hit.
-b.
Re:clean nukes are just old propaganda (Score:5, Informative)
For military the intense radiation from fission of the uranium reflector is an "added bonus". The premium in thermonuclear warhead design is on light weight and narrow diameter (long narrow-cone re-entry vehicles have much better precision than fat ones) in compromise with low cost (low consumption of expensive materials like tritium and plutonium) and high reliability.
The clean weapon was a temporary fad in 50s and early 60s, it was used by rival weapon design team to justify existence of Lawrence Livermore Laboratory and was oversold, being seized upon by politicians it got disproportionate coverage in print - but it never resulted in a weaponised design. The reality is that even a "clean" bomb designs are still an order of magnitude dirtier than Hiroshima and don't offer any military advantage so they are not stockpiled. The peaceful uses of clean nukes like digging harbors and re-livening natural gas and oil fields never materialized as it turned out that produced crater (or gas) was unpleasantly radioactive (because of neutron-induced radiation, with long-lived radioisotopes like C-14 and tritium)
Re:What about other options? (Score:3, Informative)
Did you read the full study? It quantifies the "gravity tractor" along with the other methods mentioned, the gravity tractor being the most useless, other than conventional explosives. If you don't like nuclear, a simple high-velocity kinetic impactor is the next most effective (as long as it's a single solid object).
Re:FUD alert.. (Score:2, Informative)
The only real difference between a climate sim and orbital mechanics, fundamentally, is how many variables you have to deal with. Climate sims are very, very complicated. Orbital mechanics, relatively simple. Both chaotic on long time scales.
Summary of the charts in the full study.... (Score:3, Informative)
Nuclear, Subsurface: 11.9
Nuclear, Surface: 11.5
Nuclear, Standoff - Neutron: 10.3
Nuclear, Standoff - X-ray: 9.9
Kinetic @50km/s (avg): 9.0
Kinetic @10km/s (avg): 8.5
Surface Thruster (non-rotating asteroid) @10 years: 8.1
Surface Thruster (rotating asteroid) @10 years: 7.7
Gravity Tractor, @10 years: 6.9
Conventional Explosive, Subsurface: 6.8
Conventional Explosive, Surface: 6.4
Momentum change [in log10(kg m/s)] required to deflect the following:
Hypothetical long-period 1km comet with 9-24 months to impact: 12.8
Hypothetical 1km asteroid 15yr ahead: 10.5
VD17, a 500m asteroid for 2088: 9.6
Apophis after 2029 approach, assuming a 2036 a collision prediction: 9.4
Hypothetical 200m asteroid 10 yr ahead: 8.7
Apophis by 2029 (with current orbit knowledge): 8.5
Apophis by 2029 (with highly accurate orbit knowledge): 6.3
The point of the distinction between the last two is that the probability window we have to push out of the earth's path becomes much smaller the more accurately we know the orbital parameters of the object. So the more accurately we can calculate it, the less we have to actually push it (up to a point, of course). Also, it looks like very little is gained by exploding things underground as opposed to on the surface. So we apparently aren't going to need a crack team of good-looking drilling experts after all.
Re:I, for one, welcome our... (Score:2, Informative)
Re:Summary of the charts in the full study.... (Score:3, Informative)
Not funny (Score:1, Informative)
Re:S.T.U.P.I.D. (Score:5, Informative)
I dunno... Lets ask what the Allied High Commanders and Staff thought:
General Dwight D. Eisenhower
So yeah... According to some of the major members of the US military and those who took part in the Manhattan project, the bombs were unneeded.
Re:S.T.U.P.I.D. (Score:4, Informative)
MacArthur supervised the occupation of Japan, and made sure that the Japanese food network was the first thing reconstructed; he even forbid the US forces from eating any of the scarce Japanese food. Democracy flourished, and MacArthur and emperor Hirohito became friends.
Please do not accuse the United States of attempting to humiliate Japan, because there is simply no credibility to that statement.
Re:S.T.U.P.I.D. (Score:3, Informative)
Even if we had not invaded Japan, any potential non-nuclear outcome would have been MUCH worse.
Japan depended heavily on inland water craft for transport. We had decimated this system and were in the process of finishing it off. Their railway system was very vulnerable to air attack and we were working on that two.
Almost all agriculture in Japan at the time was FAR from most of the population. If we had simply continued to bombard Japan from the air, the Japanese people would have starved to death. The estimates run as high as 60% of the population in less than a year (1944 and 1945 were bad rice years to begin with). The Japanese leadership did not care. This did not take into account the fact that ALL allied prisoners would have died, along with possibly millions in China and other parts of Asia.
Also, the USSR would have invaded more of the northern islands if the war had not ended when it did. If you think Berlin was a mess, think how bad THAT would have been.