Nike Missile Site on Sandy Hook 

Thank you for your service.

The Edison depot, was that at Camp Kilmer?

I’m no expert, but I guess its all about range, accuracy, risk and contamination. The higher the warhead yield, the bigger the range, so it increases the chance of bringing the bomber down. I’m guessing the bomber could also detect the incoming missile and would attempt evasive manouvers. But if the warhead destruction zone is a few miles in diameter, good luck with that, LOL. You don’t want to use a too powerful warhead though, because that would unnecessarily spread radiation over the sea, contaminate fish, and may spread and cause human illness along the coast. There is also wind blown radiation and fall out from winds high up that travel a long way. Because the Tupolev held bombs and not missiles, Nike command knew it was still safe to blow it up as long as it was still over the sea. So I’m guessing they could have a few goes at it, and the 40 megaton warhead could have been for the final last ditch attempt, with the widest explosion radius.

The Nike-Ajax radars could not distinguish a single plane from a formation of bombers, and the kill radius of the missile was less than the resolution of the radars. This meant that against a formation, your missile might well detonate in the middle of the formation, but you still had poor odds of hitting anything. The solution was the Nike-Hercules, with a 20 kt nuke aboard, guaranteed to take out an entire formation, if that's what the target turned out to be. It was overkill for a single plane; on the other hand it certainly discouraged an enemy from sending entire formations of bombers.

The reason a Hercules has a nuclear warhead is to destroy the atomic bomb on board the Russian plane with the extreme heat and pressures of another nuclear weapon exploding above and forward of the attacking bomber(s). Simple as that. This tactic was called a "Weapon's Kill" and was intended to take place above 50K ft. altitude and 100 miles away from the bombers target. If there was a formation of Russian bombers, a 20kt nuclear burst, far ahead and above the formation, could destroy (break wings off) or seriously cripple the attacking bombers. The Hercules always attacked from above and the warhead was always detonated by the ground-based computer, programmed to detonate the Hercules warhead far enough away to develop the most pressure and heat (fireball) to destroy the nuclear weapons on the Russian bombers. The Hercules warhead had no detonator of its own to prevent any accidents. Using a "nuke-to-kill-a-nuke" seems counter-intuitive, but was a well thought out tactic. The big problem was that when nuclear warheads exploded, they also produced, EMR, Electro-Magnetsic-Radiation at detonation. After the first warhead is detonated, the electro-magnetic emissions will blind any and all radars and disrupt communications making a second shot blind and impossible. That why contemporary air-defense missiles have ballistic (big rock) warheads. Air defense, in the missile age, is a very difficult problem to solve.

Nukes were to be used in surface to surface misssions initially. High explosive will bring down almost anythihg it gets close to, and it doesn't have to be very close.