Soviets' confusing 'star wars' signals

Can Moscow have it both ways? That is what the current back-and-forth exchanges between Moscow and Washington over negotiations on space-based weapons may boil down to.

On the one hand, Moscow is insisting that it has set no conditions for the negotiations - proposed by the Kremlin for September.

On the other, the Soviets are insisting that the US agree to a moratorium on the testing of space-based weapons before the negotiations can begin.

If the US does not agree to a moratorium, a United States commitment to negotiations cannot be taken as ''serious,'' says a Kremlin official. A Soviet commentator goes so far as to say it would be ''unnatural'' for the Soviets to enter into negotiations unless the US agrees to this.

Then, is that insistence on a moratorium a condition for talks?

No, says the Kremlin.

Yes, say a number of Western analysts.

Not coincidentally, the US has a number of tests on space-based weapons planned for this fall - tests that would presumably be precluded by a moratorium.

The Kremlin's eagerness to derail such tests is yet another measure of the seriousness with which it views the Pentagon's efforts to test space-based weapons systems, popularly known as a ''star wars'' defense system.

The Soviet Union is thought to be far behind in the sophisticated laser technology and microcircuitry that would be incorporated into such a system and is apparently hoping to hobble US efforts to widen its lead in space-based weaponry. Some Western observers believe the Soviet military, in particular, is pushing for curbs on space weapons.

The Reagan administration, meanwhile, is trying to widen the September negotiations to include ground-based medium-range nuclear missiles in Europe. The Soviets walked out on negotiations on such weapons last year, however, and seem steadfast in their refusal to re-enter talks - even if those talks might also offer a forum to put pressure on the US to limit space-based weaponry.

The Soviets refused to accept a moratorium on the stationing of new medium-range nuclear missiles in Europe until well after those earlier negotiations had begun. Consequently, some Western diplomats here find it particularly troubling that the Soviets should now be insisting on a US moratorium on space-based weaponry before negotiations can begin.

Some analysts see this as evidence of the continuing preeminence of Foreign Minister Andrei Gromyko in shaping Moscow's foreign policy. And, they add, that does not necessarily bode well for the outcome of negotiations - or, for that matter, even for an agreement that negotiations should take place at all.

After all, they note, it was apparently Mr. Gromyko who fashioned the Kremlin's hard-line policy toward negotiations on intermediate-range nuclear weapons in Europe, and who undoubtedly played a key role in the decision to abandon the talks last November.

There were exchanges between Washington and Moscow over the on-again, off-again September negotiations this week, but they proved inconclusive. Each side, it seems, is waiting for the other to make a move - although neither wants to be cast in the role of spoiler when it comes to negotiations.

Still, both sides are mindful that September is just over a month away. And, it might be added, the American presidential elections follow just two months after that. Both the Reagan administration and the men who run the Kremlin doubtless are aware that their actions between now and then could indelibly affect the outcome of not only American political contests but also the tone of US-Soviet relations for the next four years.