Ban space weapons

There does not seem to be much enthusiasm in Washington for Yuri Andropov's recent proposal to ban antisatellite weapons. The State Department does say it will ''study carefully any serious Soviet proposal.'' But Pentagon planners tend to view it as a propaganda ploy - an effort to forestall US advancement in this field. It may be that. But this is no reason not to explore with Moscow the possibilities for stopping what threatens to become a dangerous and costly extension of the arms race into outer space.

Experience has shown that the time to negotiate is before technological advances push an arms competition out of control. The United States sees itself behind the Soviets in antisatellite (ASAT) weaponry and therefore seeks to catch up and create a ''bargaining chip.'' Assuming it does, what then? Remember MIRVs? Ten years ago the US had an advantage in these nuclear multiple warheads and refused to negotiate a ban on them. Now the Russians have MIRVs, too, and there has been no arms control agreement for over a decade. With any weapons system, therefore, the US over the long run risks losing its supposed ''advantage.''

In this case, the Soviet Union got a head start on the US. It has been developing a ''satellite killer'' for some 15 years and its ASAT system is said to be operational. But the judgment of many American arms experts is that the system is highly overrated. The weapon can only attack targets in low earth orbit, so it does not threaten the vital US early warning and communications satellites at higher altitudes. The warhead on the Soviet system, moreover, is ponderous, weighing more than two tons. Launching of it is slow, and it can reach its target only after orbiting the earth one or two times.

The United States, for its part, is about to test its own ASAT. The system would enable an F-15 fighter plane anywhere in the world to launch a miniature homing vehicle designed to collide with its target. Among its advantages, the American ASAT is swift and hard to detect.

From all indications, the air-launched American weapon will be more effective than the rudimentary ground-launched Soviet ASAT, giving the US a clear lead. American defense planners must know, however, that the Soviet Union will not sit still for any US technological advance. If no effort is made to bring ASATs under control, the Russians are certain to accelerate their own program. As the Union of Concerned Scientists notes, this would put US national security at even greater risk because the US, more than the Soviet Union, depends on satellites for early warning of strategic attacks and communication with its armed forces around the world. In time of war, America's ''eyes and ears'' in space could be destroyed.

As the pace of ASAT development quickens, the two sides should have the good sense to return to the negotiating table. Talks on the control of antisatellite weapons were launched in 1978 under President Carter. Little progress was made, however, and the talks were broken off after the Soviets invaded Afghanistan. Now that the US has a vigorous program under way, the Russians seem ready to negotiate. They have in fact tabled a draft treaty at the United Nations - a flawed one, from the US standpoint, but at least representing an opening Soviet bid.

For both the United States and the Soviet Union, an agreement banning antisatellite weapons in space would save enormous resources and, most important , enhance security and global stability. ''Star wars'' may make for exciting movie and television entertainment. Mankind must not risk their becoming a reality.