Space-based Ballistic-Missile Defense

The feasibility of several elements of the Strategic Defense Initiative is evaluated. Attention is given primarily to efforts to develop weapons for boost-phase interception and destruction of ICBMs, due to the difficulties in intercepting ICBMs at any other phase of flight. Among the specific systems discussed are: permanently orbiting laser weapons; pop-up interceptor missiles with directed X-ray lasers; ground-based lasers with orbiting optical elements; chemical laser weapons; neutral-particle-beam weapons; and nonexplosive homing vehicles stationed in low earth orbits. It is shown that all of these technologies have extensive defects which could render them unreliable as defensive systems for the entire country. The introduction of countermeasures and the enemy's ability to the number of missiles deployed are seen as insurmountable obstacles to any efficient defense from strategic attack. It is concluded that the questionable performance of such a defense, the ease with which it could be overwhelmed or circumvented, and its potential as a destabilizing antisatellite system could adversely affect U.S. security.