Chinese Paper on SDI and Directed Energy, Microwave Weapons Published by NAIC (pdf file)
The Strategic Defense Initiative or SDI (also known as “Star Wars”) proposed by the United States in the eighties was a plan to set up a multi-layer defensive system in outer space. The basic idea behind multi-layer defense was to divide the flight orbits of invading ballistic missiles into four stages, and to take different defensive measures at each stage. In this way, the forward defensive stages could reduce the threat to the latter stages, and the latter stages could play a supplementary role in intercepting ballistic missiles that penetrated the forward stages. The four stages of SDI were: booster stage defense, late booster stage defense, mid-orbit defense, and last-stage orbit defense. The defensive weapons in SDI were newly-developed kinetic weapons and directed-energy weapons, including microwave weapons. SDI was primarily directed against the Soviet Union. Therefore, SDI will be affected by the disintegration of the former Soviet Union. But the desire of military superpowers to develop non-chemical-energy replacement weapons will not disappear, and steps to develop directed- energy weapons, including microwave weapons, will continue.