WE DRAW considerable reassurance from the way the U.S. government and those of the other involved nations dealt with the problem of that crippled Soviet satellite. A nuclear reactor tumbling out of control through the skies is an invitation to mass hysteria or an extremely nasty international incident. But the radar systems worked; the right governments cooperated with each other; and the precautions against disaster that could be taken were taken. Fortunately, the satellite cooperated, too, by burning up in the atmosphere over a sparsely inhabited part of Canada.

There is no way of knowing whether an announcement last week that this satellite was out of control would have set off a public panic. High administration officials feared that if would, if not in the United States then in some other nation where the distinction between a nuclear reactor and a nuclear explosive is not so clearly understood. That fear should not be shrugged off lightly. Once such a panic had begun, it could not have been ended as quickly as that set off by Orson Welles's famous "War of the Worlds." In that case, it was necessary only to expose a hoax. The satellite and its radioactive threat, on the other hand, were real, so there was little to be gained - and much to be lost - by an official announcement alerting the world to a hazard as unpredictable as this one. No one knew when or where the satellite would come down or what damage it might cause. But no one on earth could do anything to stop it from coming down. With those uncertainties - and that inevitability - the government was right to withhold the information it had until it knew what was happening.

The reassuring aspect of this incident, however, lies in the sequence of events over the last few weeks. A computer of the North American Air Defense Command flashed a warning more than a month ago that something strange was going on. No one panicked. Word was sent to Washington, and the intelligence agencies went to work. When it became clear that the satellite was coming down, the government asked the Russians for information about it. An incomplete answer resulted in a second query, and the Russians then responded with the data our government believed it needed. That sequence is important because this is not likely to be the last incident of its kind. With as many satellites and as much "garbage" as there is in space now, the odds are that other unpredicted events will occur. It is comforting to have had a demonstration that the radar systems work, the data is properly analyzed, the right people are told and - above all - that the two nations that have put most of the stuff up there can cooperate when a great deal is at stake.