Part of me gets that you can't "kill" an asteroid, and that a giant rock moving towards the earth would just be turned into many smaller rocks moving towards the earth... but that said, I think this sort of thing still might be useful, and I'd love someone to explain to me otherwise.
First, small rocks more easily burn up on their way down. So smashing a big rock to pieces increases the surface area enough that maybe that can make it safer for humans.
Secondly, perhaps the energy hitting the big rock would 'deflect' it ever so slightly. Fire it early enough, and you can make it completely miss the earth.
As a deflector (launched years or decades from impact), you can nudge the impactor out of its present orbit by gently ablating one side from a distance; You can do this iteratively until the impactor's orbit changes enough to miss Earth.
Decades is sufficient for some of the continuous-thrust alternatives, though, depending on scale.
As a point defence weapon (launched weeks or months from impact), you can send the nuke in as close as possible and detonate in order to break up the body. Yes, this would cause lots of smaller impactors, but over some size ranges it's preferable because ablation is insufficient. If 99% of the smaller impactors miss Earth, we win... in some cases.
Just breaking up a large impactor (at the very last minute, launched minutes or hours before impact) doesn't help so much if everything still hits Earth, because a planet-killer turns into hundreds of city-killers randomly spread out.
On the other hand, a small impactor could be dramatically affected by a nuke, with plausible amounts of vaporization going on. There's quite a lot of risk surface in small impactors, and they would be hard to spot until very close.
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Bong Wie is working through a NIAC grant on the problem:
One interim observation: a nuke which detaches from a small cratering round which hits first, digging a hole for the nuke to fit in, would multiply its effectiveness severalfold.
It's a very different problem in each different size class of impactor (as well as orbital classes). 10m, 100m, 1000m, 10000m are all of concern in unique ways; each order of magnitude increase in diameter raises mass by three orders of magnitude.
> Just breaking it up (at the very last minute, launched minutes or hours before impact) doesn't help so much if everything still hits Earth, because a planet-killer turns into hundreds of city-killers randomly spread out.
Wouldn't smaller objects burn up a greater proportion of their mass in the atmosphere (due to the increase surface area) and kick up less of a dust cloud once they impact? Could hundreds of city-killers leave some areas unscathed and still populated and habitable?
I think it would be a great help if a planet-killer could be downgraded to a civilization-killer or even a species-killer.
If you can choose between one massive impact and two half-sized impacts, surely the two half-sized is better? The air can absorb more of the impact on each smaller rock, and the dust kicked into the atmosphere would be less than half for each smaller impact (right? wrong? correct me, please).
Hard to say how many rocks you could break a big asteroid into, but I suspect it would still be a much more optimal outcome.
Plus, we could convince the major superpowers to fire all their nuclear arsenal into space. I am all for that.
Impact energy would rise with the cube of the diameter, I guess. So splitting up one large asteroid into a swarm of smaller ones is desirable. With any luck, some of the debris would even miss.
The bigger problem is that that kind of missile system can be easily weaponized (China and the US have successfully tested satellite killers and the USSR maybe too), so simply enhancing ICBMs for that without international oversight is problematic.
That relation is equivalent to conservation of mass, and wouldn't account for any energy losses. As the asteroid is fragmented, its total cross section rises, increasing energy deposition in the atmosphere, reducing available energy for ejecta.
WRT to arms-control regimes: What's the difference between an asteroid-killing BM and an ICBM? Only the warhead count. START inspectors would count such a launcher toward the cap.
If you can guarantee just three cities. Either way, not sure why I was downvoted for having an opinion on the matter. Also I'm wondering why HN moderators allow such downvoting which discourages well intended discussion and participation.
If you believe this you are pretty naive. The space program was initial started to support Starfish Prime type high altitude nuclear tests.
All launch vehicles until Apollo were ICBM's. The moon landing was originally planned to be a diplomatic stunt by JFK who wanted a peaceful mission to open a larger diplomatic dialog.
Space programs have always, and likely will always be a way to project power. And test high end military weapons under the guise of peace and science.
First of all it would be great if you didn't insult me to bring across your point.
The second thing I'd like to say: I never contradicted any facts you state here. Likely they will be using the data to improve their ICBM's, it would be an enormous waste of resources if they didn't. (and so does every other country that has ICBM's)
I said: nothing indicates that they will use a nuclear weapon, "it is all about the delivery mechanism" -> they will use ICBM's but without the warhead, which does not break any treaties to my knowledge.
We never really stopped testing nuclear weapons. After the ban, we continued using supercomputers to perform the tests, which, given how powerful the supercomputers are, is just as good as testing the real thing.
I think any engineer or developer would agree that we only know a technology works after testing it, not just because it works on paper. I wonder how the US or Russia can really have any confidence in any nuke designed since the early 90s.
>Air-launched weapons like cruise missiles must endure hours of sub-freezing temperatures at high altitudes while riding their carrier aircraft. Weaponeers successfully subjected the W-80’s components – including the IHE – to temperatures down to -65 Fahrenheit – during development.
>But when actually tested in Shot Baseball during Operation Guardian in January 1981, the W-80 fizzled. The new nuke failed to ignite its fusion secondary and produced only a fraction of its intended yield. The IHE proved to be the culprit. It didn’t burn well at very low temperatures.
> I doubt that Russia or the US needs to really test nuclear weapons at this point, it is all about the delivery mechanism.
IIRC, there's still some need to test in order to evaluate the performance and other aging characteristics of old warheads. The US, at least, is trying to accomplish that testing via simulation rather than actual detonations. though.
The United States continues to invest billions of dollars in advancing nuclear weapons science (NIF,ASCI,LEP). A critical detonation of a weapon is unnecessary. There is plenty of useful data available from a long-term program such as NIF, which DOE uses to refine physical simulations of weapons phenomena.
> Russia and the US are more than capable of destroying the world already
They aren't capable of destroying the world; their definitely, OTOH, capable of really dealing a severe blow to human civilization and might even manage to wipe out humanity entirely.
If you just detonate all nukes at their own silos, fallout & nuclear winter will wipe most of life in a few months. If you want to demolish the whole Earth DeathStar-style, nukes won't help.
If USSR would get capability to kill GPS satellites, U.S. nuclear subs could not target their missiles anymore. The rest of U.S. nuclear arsenal is in B2 bombers in known airfields and ICBM's in known silos. So by using their ICBM's to knock off airfields and silos, USSR could theoretically kill U.S. nuclear cabability withouht being hit.
GPS was created for U.S. nuclear subs. The problem is about knowing where the sub exactly surfaces, because after launch, the trajectory is ballistic. Subs have very good inertial navigation, but the accuracy deteriorates with time and movement.
TERCOM is very nice, but only applicable for cruise missiles flying close to ground and able to change their course.
> If USSR would get capability to kill GPS satellites, U.S. nuclear subs could not target their missiles anymore.
While GPS might be used to refine locations, both subs and their missiles use inertial navigation that isn't dependent on satellite clusters. A long term lack of GPS would hurt accuracy, but a Russian attack on the GPS system would be such a provocative act that its direct long-term effects on targeting and navigation would probably be insignificant compared to the indirect long-term effects by way of the broader conflict it provokes.
Missile subs can work just fine without GPS position fixes - maybe not as accurate, but just as fine.
Since by definition the US missile sub fleet would be used for a second strike role in this situation (by definition, since someone else nuked the satellites first), the strikes would primarily be retaliatory in nature - ie, nuke the cities. Big whoop if your CEP is now 500m when you're nuking Moscow.
Every statement in here is wrong, but the greatest error is this: the most potent leg of the US triad is invulnerable to the threat you describe, and is capable of annihilating the USSR. Yes, US SSBN's are equipped with time-travel technology to destroy the Russian arsenal before its designers were even born.
This is potentially a powerful statement for Russia, though the article doesn't make it clear if the weapons are designed to break up the asteroid or redirect it. If the latter, it's extremely threatening: if you have the capability to deflect an asteroid to miss the earth, you can just as easily deflect one to hit.
The article describes the asteroid Apophis as coming dangerously close but doesn't mention that it's not deemed a threat anymore.
It's good PR for Russia's military power though if it could be done.
First, small rocks more easily burn up on their way down. So smashing a big rock to pieces increases the surface area enough that maybe that can make it safer for humans.
Secondly, perhaps the energy hitting the big rock would 'deflect' it ever so slightly. Fire it early enough, and you can make it completely miss the earth.
Thoughts?