So you’re saying other than a burst of hard radiation, a 50kt detonation a mile from a fairly fragile structure would have little effect? That the cone of superhot particles alone would cause little damage?
Remember that the total mass of those super hot particles would be a few tens of pounds. And the vast majority of it would be directed in directions where it doesn’t intersect the target. I estimate that at the distance of a mile, the cross section of the ISS is about 0.005% of the total sphere.
This is definitely not correct. During the Trinity test, they were initially going to place the 20 kt device inside a large container, so if it fizzled they could scrape off the precious plutonium from the inside: http://www.atomicarchive.com/History/trinity/images/SB42.jpg
However they later calculated even the full 20 kt detonation would not vaporize the container – even if detonated INSIDE it. There was danger the molten metal or shrapnel would be flung into people or structures. The “Jumbo” container was not used.
The 20 kt explosion did not even fully vaporize the tower legs which were only 100 feet away: http://www.trinityremembered.com/photos/afterwards/Oppenheimer_and_Groves.jpg
The Hiroshima bank was almost directly beneath the 15 kiloton bomb when it detonated at an altitude of 1,900 feet, yet Akiko Takakura inside the building survived and I think she’s still alive today at age 92:
http://www.geocities.jp/s20hibaku/photo/koe_118.jpg
http://www.hiroshimapeacemedia.jp/wp-content/uploads/2014/08/c3c88684504af0e570e338515fa63fb7.jpg
A nuclear warhead detonating in space would release radiation energy (not heat) evenly in all directions. It would likely vaporize a flimsy one ton vehicle and bomb casing.
If the average specific density of the one ton device was 1.0 (water), the unexploded volume would be 1 cubic meter. At a distance of one mile the surface area of that sphere is 32.5 million square meters. If evenly distributed across 32.5 million square meters the material would form would be an outward-traveling shell having a thickness of 1/32000 of a millimeter, or 1/3 of a nanometer. It would be far thinner than a soap bubble.
I’m not saying ISS would not feel anything but it is unlikely it would be structurally damaged by a 50 kt device detonating 1 mile away.
There was 82 successful launches to LEO in 2016, so approx one every 4 days on average. Assuming world wide global cooperation, you could just grab which ever rocket was prepped closest to a launch and replace it’s cargo with the remote detonated nuke then wait for the launch window.
It looks to me like the ISS can be reached from almost any space port regardless of location, is that right?
The USA fired a missile into space to destroy one of their own satellites a few years back, it was a direct hit, with complete destruction.
No nuclear weapon is needed. Currently there are lasers that can burn through steel and heat up materials, which would cause the space station to explode.
Sure but the point was not “how to destroy the ISS” it was how could we completely obliterate every trace of it with a nuclear weapon. Eg lets imagine that rogue nanotech “grey goo” has taken over the ISS and will destroy the entire world unless we nuke the ISS*.
So what about if we take the biggest current US warhead (1.2 megatons) and launch them on one of the ICBM’s thats immediately available. Even though it doesn’t have terminal guidance we only need a near miss and if it’s “save the planet time” well the US has plenty of ICBM’s just launch all of them aimed in the right direction, one of them will probably be close enough**
- Micheal bay I want royalties if you take this idea …
** note whatever this does to the earths ozone layer, magnetic field, whatever is not my problem. The OP asked how quickly could we nuke the ISS, they didn’t mention that humanity / civilization has to survive the process. 
The only US ICBM left is the Minuteman III which likely does not have the payload capacity to lift a 1.2 megaton W56 to the 250 mi. orbital altitude of ISS. There are probably lighter weight and lower-yield devices which could be used, but they’d be in the 100s of kt range.
There is a finite payload capacity for a given destination and a yield-to-weight ratio limit for the warhead: Nuclear weapon yield - Wikipedia
For a terrestrial target the Minuteman III inertial guidance can achieve about 200 meter accuracy, on average. However that is a fixed, pre-surveyed target on earth’s surface. Tiny perturbing influences on the trajectory such as gravitational anomalies, coriolis force, etc are all extensively pre-surveyed and modeled – only for that exact flight path.
For an orbital target this would be totally different. Since there’s no alterable in-flight or terminal guidance, the orbital track of ISS would be calculated then the inertial nav on the missile programmed to blindly reach a point in space at a specific instant – three spatial dimensions plus time. The missile would be on a closing velocity of several km per second, and intersecting the ISS orbital path at an angle.
Even if the inertial nav could achieve a point in space within several hundred meters, that’s not good enough. The detonation would have to happen within millisecond precision – based on pre-calculated timing. There is no radar fuzing on an ICBM warhead. ISS is traveling at 7.6 km per sec, at an angle to the ICBM flight path.
Imagine trying to hit a bullet with a bullet if the guns are aimed at each other – pretty hard. It’s mostly a 2-dimensional aiming problem. If the timing was off one bullet could theoretically go own the other’s barrel.
Now imagine doing that with the guns fired at right angles – a perpendicular strike. It’s a 3-dimensional aiming problem plus an exquisitely precise timing problem. Intercepting an orbital vehicle without terminal homing is like that.
Each attempt would probably miss by several miles. As already mentioned, a warhead in the 100s of kt range would require almost a direct hit to completely vaporize ISS.
Radar or proximity fuzing could be added to the warhead but that’s not part of the design and would require engineering, integration and testing. For existing ABM weapons that technology already exists and is deployed, but they are mostly kinetic warheads that use “hit to kill”. So even in that case the kill vehicle guidance would require integration with fuzing logic for the nuclear warhead. You couldn’t just strap a warhead on the KV and launch it. Gravity (ie free-falling) bombs have radar fuzing but it’s not designed to work at an intercept velocity of 23,000 feet per second.
Fiction usually depicts space vehicles and asteroid belts as cluttered, visually close and accidental collisions as frequent. This is incorrect, highly misleading and only done for dramatic purposes. In reality space is vastly empty, objects are microscopically small by comparison, delta-V to change trajectories is very limited, and intercepts are incredibly difficult. This is partially covered by the “Big Sky Theory”: Big sky theory - Wikipedia
What if the Russians do it? Could they deliver a Tsar Bomba (this is case where we REALLY want to be sure!) on one of their Protons?
According to the Wikipedia article on Tsar Bomba, it weighed 60,000 pounds, while the article on the Proton rocket family says they can currently put 50,000 pounds in LEO. From playing SimpleRockets and Kerbal Space Program, I can tell you with great authority that this means you just have to duct tape two rockets together.