The possibility of laser weapons ignited the imagination of both mundane people and military engineers as soon as the Laser was invented in 1950's, as it promised instant destruction and unlimited range, but the technological difficulties of creating laser weapons proved to be great. When the USA decided to break treaties on non-developing ballistic missile defences in the early 1980's, one of the components of their famous SDI, or "Star Wars" program were land- or satellite-based lasers, that could be deployed to shoot down nuclear missiles. Again, while theoretically possible, early laser weapons only had very limited effectivity, but they were continuosly developed during the next decades. Until 2010, there wasn't any which moved past the prototype phase. Lack of rapid progress in developing laser weapons could be attributed to many factors, but the lack of apparent need for them at the time might be the most important one.