non-nuclear weapcns. The task- for instance, of countering an attack when the missiles are already ulder way would involve the fornidable task of destroying,individually, thousards of re-entry vehicles. This is not practically feasible by using nucfear lreapons. Other nethods that ar-e being considered hy military p] anners include high-energy fasers and neutral particJe beams. These would haveto be based in space, either in 1ow-earth or synchronous orbit, so that the beam could be directed at the nultiplicity of targets during the feu minutes availabfefor their desLructior, This voul-d. in any case require the destrucLion of many hundreds of targets within a few hrmdred seconds fr^h a r^noa af ln nnQ fta. {9 l+0 ,000 kn" 1IB. Laser beans coul-d beat the surface of a missile in space, while energeticparticle beams may penetrate deeply into the missife and interfere with the electronicsr melb fissil-e material, etc. However, it is an open question whether energy in arolrnt s like1y to d.amage a re-entry vehicl-e or a rocket booster could be delivered in the short time avai].able to destroy hundreds of offensive veeponsin a few ninutes. This task vould also require an entire system of varning, assessment, direetion, comnand, control, energ'y supply, and the like. Furthermore,this system wou1d have to operate under conditions when it, too, woul-d most probably be brought under attack. 119. Both laser- and particle-bean systems are currently in an expfot'ative researchstage" Hovever, strong doubts have been elrpressed that any of these techniques would ever be useful for an operational defence against ballistic nissiles. 120, In the past 15 years, there has been a vasb improvenent in the quality andavailability of anti-aircraft systems. fhis includes surface-to-air missile systems as ne11 as fighter aircraft equipped with air-to-air nissiles. In either
**Analysis**
The text appears to be discussing the development of technology to counter ballistic missile attacks, specifically the challenges and limitations of using non-nuclear weapons. It mentions various methods being considered, such as high-energy lasers and neutral particle beams, and the difficulties in destroying hundreds of re-entry vehicles in a short amount of time.

**Category**
Science and technology, Defense