The Rulison test — conducted at a depth of 8,425 feet — was the deepest subterranean nuclear-bomb detonation conducted in U.S. history.

To protect Allied astronauts and spacecraft, U.S. commanders need to stage a preemptive strike on Russia’s atomic-armed ASAT missile before it can be launched into orbit.

A top arms diplomat at the State Department recently laid out what might come next as Washington upends decades of federal policies on nuclear proliferation.

C ould nuclear bombs be harnessed to help people? As the Cold War raged on in the 1950s, scientists building nuclear weapons began to ponder whether they could be put toward posit ...