SDI - Strategic Defence Initiative

The Strategic Defence Initiative was commonly referred to as Star Wars after the popular science fiction films of the time. This initiative was proposed by the American President Ronald Reagan in 1983.

The intention was to use ground based and space based systems to protect the United States from attack by strategic nuclear ballistic missiles. The focus was strategic defence rather than the previous strategic offence of Mutually Assured Destruction.

The vision was to have the ability to create a curtain in space of x-ray lasers powered by nuclear explosions. This curtain would be able to deflect and so negate any nuclear ballistic attack from the Soviet Union on America.
The initiative was never fully developed or deployed but the research and technological development that took place has influenced some of the missile systems in use today.