Russia is developing a nuclear space-based weapon designed to target American satellites, three sources familiar with the matter told NBC News. This weapon is not yet operational and details are limited due to the intelligence being classified. It's unclear if this actually involves nuclear warheads or nuclear-powered satellites carrying electronic weapons. Deploying actual nuclear weapons in space would violate the 1967 Outer Space Treaty. A nuclear-fueled satellite could potentially carry a high-powered communications jammer.