Missile Defense has been a big thing over the past decades to one day stop Intercontinental Ballistic Missiles. (ICBMs)Today's Missile Defense system is limited and the only defense against ICBMs is Mutually Assured Destruction. But that may change in the future. Early programs like Nike Zeus relied on nuclear explosions while the missile reentered the atmosphere. Nuclear explosions in space were proposed during Ronald Reagan's "Star Wars" program, but EMP from upper atmosphere explosion might damage satellites of the Star Wars programs. However today's military satellites and ground radars can very shielded against EMP unless they were very close to the blast. US Missile Defense still relies on kinetic kill vehicles to physically slam in the warhead. But in a full out nuclear war, can a nuclear missile be used to stop another nuclear missile if it was in accurate proximity?(lets say 200-1000 meters, accuracy range for most ICBMs) However, nuclear warheads can be shielded as well. Nukes are not very damaging heat and shock wise in space since there is no atmosphere to deliver that massive heat cloud, nor is their air to make that big shock wave. What greatly increases is radiation, but are they damaging enough? How resilient can a metal case be to nuke radiation, especially if they need thrusters and holes to maneuvers? Also does it produce a small blast and fireball at least in a couple hundred of meters for lets say a 500 Kiloton warhead?