U.S. President Ronald Reagan announces the Strategic Defense Initiative (SDI). Commonly known as Star Wars, SDI is envisioned as a satellite-based nuclear defense system, which would destroy incoming missiles and warheads in space.March 1983: Star WarsU.S. President Ronald Reagan announces the Strategic Defense Initiative (SDI). Commonly known as Star Wars, SDI is envisioned as a satellite-based nuclear defense system, which would destroy incoming missiles and warheads in space.