During the late 1960s, a top-secret Soviet program to sneak nuclear weapons around U.S. early warning radars was mistaken for a rash of UFO sightings by Moscow’s citizens. WikipediaThe “UFO” sightings were actually test launches of the R-36 Orb, a secret nuclear space missile. Related Story Inside the CIA Plan to Steal Soviet Missile DataThe R-36 was a so-called “first strike” weapon. Resolution 1884 , passed in 1963, which called on the U.S. and U.S.S.R. not to place nuclear weapons in space. Wikipedia Ground-based radars such as this Pave Paws system in Colorado helped make the R-36 surprise attack mode obsolete.