CRITICS OF the Reagan Administration's proposed Strategic Defense Initiative (SDI) have long understood the impossibility of developing a be-all-end-all military technology. But not until this week has the Department of Defense (DOD) itself conceded that the President's "Star Wars" vision could become one of the world's more costly anachronisms before its development is even approved.

The problem, as outlined in a classified report from the Defense Intelligence Agency, is the possible development of a new Soviet weapon--the "fast-burn" rocket. According to the report, such a device could speed into orbit and shut down its engines before the heat-seeking sensors of SDI satellites could home in on its jetstream. The report predicts that the Soviets could "develop, produce and deploy" fast-burning rockets as early as 1993.

The advent of fast-burn technology could cast a terminal gloom over any feasible Star Wars defense system. With a boost phase of only two minutes--less than half that of conventional weapons--fast-burning rockets could penetrate the atmosphere and detonate their "throw-weight" of multiple warheads in substantially greater numbers than proposed SDI equipment could contain.

Reactions at the Pentagon illustrate the pitifully short-term view of world peace held by many pointy-nosed bureaucrats. Even before the report had been acknowledged by the SDI office, one human cog in the military-industrial machine was busy refuting its conclusions. Speaking on the condition that he not be identified, the official ventured that, in his opinion, the Russians would not be able to develop a fast-burn rocket for at least fifteen years.

Fifteen years. Please join me in a polite cough. For a mere trillion-dollar investment our nation can attempt to produce a space-based military technology that, by its own estimates, should attain obsolesence within a decade of its conception.

One would hope that the world's oldest democracy could understand the remoteness of the goal which its present Administration would like to achieve. American ingenuity may have enjoyed its triumphs, but science has never before been asked to develop a technology immune to progress. Future thinkers and further technological developments are destined to challenge a space-based defense system, and whether they succeed in 10 years or 20 is of relatively minor significance.

With the built-in obsolesence of the proposed Strategic Defense Initiative acknowledged by the DOD's own intelligence agency, the absurdity of Star Wars becomes increasingly obvious. Escalation of the arms race into space offers no viable solution to a world in search of a lasting peace. In the end, this nation will have to rely upon something more substantial than technology to remain leader of the free world.