Very interesting thanks but how would a gravity sensor tell you if there is a nuke there? Is it because of the greater mass of uranium or plutonium?
Yes, they basically get an idea of mass density distribution in the warhead, while fissile materials and radiation shielding are necessarily very dense elements, and things like explosives and chemicals are fairly low density, so if there's very dense stuff in the warhead it's probably a nuke.
That says IR so it tracks the heat from the rocket launch and exhaust. But wouldn’t a railgun have very little heat no more than artillery or a tank round how could you tell between a conventional railgun tank and a metal gear with a nuke.
All missiles, the bigger the more so, create said heat. Telling if it's nuclear tipped or not usually depends on other intelligence, like what i mentioned, or knowing which missiles are nuclear only and so on.
Same way, you have nuclear artillery shells, but those have flight time and range so short that the most obvious way to tell it was nuclear is by the very obvious nuclear explosion.
Also I have a question about helicopters if it gets shot down is there a way for the pilots to eject? Because they can’t do it the same way as an airplane or the propeller would slice up the pilot after he ejects like an onion on an infomercial. So are helicopters flying coffins or is there some way to get out if it’s about to crash?
Outside of Ka-52 (which has its own risks) or jumping out the door with a parachute like in WW2, no.
There's also autorotation, which, if pulled off, means the helicopter crashes at low velocity so the crew may be able to walk away from the crash with no or at least limited injuries.
Again how could you differentiate between that and the white noise? Because the heat of a fired handgun also gives off energy but picking it up won’t help to detect the nuke and know it’s a nuke and not something else.
A lot of said detection relies on the assumption that if it's a fatass intercontinental weapon fired by a nuclear power, it's probably a nuke, because using such expensive delivery mechanisms for anything else isn't really worthwhile.
There may also be ways to detect the radiation signature of a warhead.