AS the Western news media continues to swoon over Soviet glasnost and its revelations about some Soviet secrets, Moscow has just provided a jarring reminder of where the limits of openness remain. Another Soviet space nuclear accident is in the making, and Moscow has reverted to pre-Chernobyl-style denials, cover-ups, and lies. For most of April, Western space watchers were keeping their eyes on the Soviet satellite Kosmos-1900, launched last December. As it skimmed the atmosphere on its naval reconnaissance mission frequent altitude boosts were needed to restore height lost to air drag. But by mid-month, the watchers noted with interest and growing alarm, the weekly boostings had ceased and the satellite's altitude was steadily dropping.
Aboard the Soviet satellite is a nuclear reactor to power its radar system. Over the past 20 years, dozens of this type of satellite were launched into low, unstable orbits on military missions. Although most safely boosted their radioactive cargoes into high, graveyard orbits, in 1978 and 1983 two tumbled back into the atmosphere, causing worldwide concern. In 1969 and 1973 two others fell back to Earth during launch phase, without public awareness or Soviet admission. Western analysts called them RORSATs, for Radar Ocean Reconnaissance Satellites. The Soviets labeled them ``Kosmos'' research satellites for peaceful scientific investigation of the universe. Moscow was lying.
By May 10, the Kosmos-1900 had gone a month without altitude boosts and slipped well below the normal operating range. Clearly something was wrong and it was falling back to Earth out of control. Geoffrey Perry, a respected British space watcher and leader of the ``Kettering Group'' of amateur satellite trackers, told his news contacts that the satellite's uncontrolled orbital decay hinted at some sort of failure, and at the prospect of another Soviet space nuclear accident.
The announcement in London prompted Moscow to respond with a brief acknowledgment. They had known about the failure for a month, but announced it only two days after Mr. Perry revealed it. The official Tass statement admitted ``radio contact with the satellite was lost in April 1988,'' and that it would fly in orbit ``till August-September 1988'' when ``it will cease to exist.'' Moscow admitted there was a reactor on board but claimed the satellite ``has systems ensuring radiation safety on completion of the flight.''
However, knowledgeable observers realized this statement consisted almost entirely of evasions, distortions, omissions, and lies.
Moscow did not even admit the obvious: The satellite was going to fall back into the atmosphere and spread radioactive contamination over the Earth. They implied it would just vanish.
The timing of the fall, late summer, depends entirely on another feature mentioned by Tass: the ``oriented flight'' of the satellite. Out of touch with Earth, the satellite's simple-minded autopilot is keeping it pointed small-end forward ``into the wind,'' minimizing air drag and the consequent orbital decay. But possibly days or weeks from now the satellite's fuel supply will be exhausted, and the small directional rocket thrusters will cease to function. Then the satellite will tumble aimlessly, presenting its broad side to the air drag and accelerating its decay rate. Judging from past Soviet space failures of this type the time from loss of orientation to final fall is only three or four weeks.
The phrase about ``ceasing to exist'' is nonsense. Satellites which fall back into Earth's atmosphere are subjected to immense destructive forces, both from deceleration stress and from the heat of atmospheric compression. Numerous large and small fragments survive to reach the surface.
The safety systems on Soviet RORSATs include a feature added after Kosmos-954 strewed northwestern Canada with radioactive debris in January 1978. It now allows the reactor core, containing the most dangerous isotopes, to be ejected from a falling RORSAT and hence burn up high in the air, diluting the isotopes far and wide. This happened when Kosmos-1402 fell out of orbit early in 1983 and the free-flying reactor core burned up, arguably harmlessly, over the Indian Ocean. This time, that safety feature has evidently failed. The reactor core has not yet been ejected from Kosmos-1900 and now probably cannot be. Ground operators cannot control it anymore, and any dead-man circuit that could have fired automatically probably would have fired within a few days of the loss of control. It did not.
The result is that the highly-radioactive reactor core will fall back to Earth protected by the main satellite body, three tons of metal shielding. As in Canada in 1978, dangerously ``hot'' pieces of scrap metal are going to hit the earth's surface.
This might occur over the ocean and endanger only the whales. Or it might occur over land between latitudes 65 North and South. The risk is not that someone might be hit on the head. The finite danger is that passers-by in an inhabited area might pick up the scrap. In 1978, pieces recovered in Canada were sufficiently radioactive to kill anyone who kept them nearby for several days.
Yet the Tass statement assured the world that the satellite would cease to exist and that radiation safety was ensured. By Moscow's word, no search, recovery, or decontamination efforts will be needed.
The Soviets themselves clearly recognize the danger they deny. Even the fuel-expensive technique of boosting their used-up satellites into a permanent orbital graveyard is testimony to their private concern, since other used-up satellites (without reactors!) are dumped back into the atmosphere over the remote southern Pacific Ocean. If the ``safety systems'' on the RORSATs are so perfect, why don't Soviet space controllers dump the old satellites onto Siberia and save fuel and complexity? They don't because they know it would be dangerous.
On May 13, at a Washington, D.C., press conference that turned out to be incredibly ill-timed, top Soviet space scientist Roald Sagdeyev joined with the Federation of American Scientists (FAS) to call for a ban on nuclear reactors in space. Their target clearly was the US SP-100 program under development for the Strategic Defense Initiative, but some reporters asked Mr. Sagdeyev about the Soviet RORSAT program. He denied any specific knowledge about it except what he'd read in the Western press. And although the Sagdeyev/FAS motivation for banning all nuclear reactors in space was supposed to be safety, nobody at the press conference was willing to admit that Soviet assurances of perfect safety with Kosmos-1900 were phony.
Moscow refuses to discuss the satellite's true military mission, or to provide photographs of the vehicle and its reactor. It refuses to help other nations prepare search and decontamination procedures (while probably dusting off its own secret contingency plans). Without pressure in the form of pointed inquiries from skeptical Western newsmen, Moscow's stonewalling continues.
It may take radioactive reality, in the form of official disinformation over a genuine Soviet space disaster, to shock many Westerners out of their euphoria over glasnost.
James Oberg is the author of ``Uncovering Soviet Disasters: Exploring the Limits of Glasnost,'' Random House.