Future historians could well look back on the South Korean airliner affair that has dominated the world's headlines for the past 10 days as a textbook study of how the Kremlin reacts to unforeseen military and diplomatic challenges.

The successive reactions from Moscow of silence, evasion, grudging acknowledgment that one of its planes shot down the jumbo jet, and righteous indignation against the West are already being analyzed by Kremlinologists for the insights they provide into the Soviet system and the Russian obsession with security.

The case also provides some clues about the style of Yuri Andropov, the new Soviet leader, as he attempts to juggle foreign pressures and domestic constraints in his first major international crisis.

By comparison with the flood of information that comes out of Washington and other western capitals every day, the glimpses that the Kremlin has allowed outsiders of its decision-making processes since the airliner was downed have been meager.

But, if compared to the usual blackout on sensitive security matters, they have been revealing. And in certain respects--such as the news conference yesterday by the armed forces chief of staff--they have been unprecedented.

Many pieces of the complicated jigsaw puzzle remain to placed, and some will never be known to the outside world. But it is now easier to answer two vital questions that have troubled many people in the West: why did the Soviet Union jeopardize some of its most important foreign policy aims by shooting down a civilian airliner with 269 persons on board, and why, having done so, did it react in a way that only compounded the original blunder?

The destruction of the jumbo jet seemed so inexplicable at a time when the Kremlin was seeking to mobilize the support of peace groups in Western Europe that some commentators in the West immediately smelled a conspiracy. The Soviet military, they reasoned, was unhappy with the "peace initiatives" launched by Andropov and his offer to destroy Soviet SS20s in return for the nondeployment of American missiles in Europe. The shooting down of the plane effectively sabotaged renewed stirrings of East-West detente.

This theory is dismissed by both Western and Soviet analysts in Moscow. The truth appears to be somewhat simpler and to reflect a mixture of the traditional Russian obsession with security and the strict division between military and civilian areas of authority and chains of command in the Soviet Union.

There seems little reason to doubt the assertion by Marshal Nikolai Ogarkov at his news conference that the decision to shoot down the Korean Air Lines plane was taken by a local air defense commander in the Soviet Far East. It is unlikely that, in issuing the order in the early hours of Sept. 1, the commander considered the damage that would be done to the Kremlin's image abroad. He had specific standing instructions about what to do in the event of serious border violations, and he carried them out to the letter.

At the news conference, Ogarkov said the Soviet commanders reached the conclusion that the South Korean plane was on a spy mission by the simple fact that it was 300 miles off course and was flying over top-secret military bases.

Ogarkov insisted that it was absolutely out of the question that this could be anything but an intelligence-gathering flight. And he repeated the word "absolutely" several times, nodding his head for emphasis.

Now either Ogarkov is an exceptionally good actor or what he was saying must be taken at face value, in which case it provides a useful insight into the Soviet military mind. The idea that a foreign plane, whatever its size and external markings, could lose its way over sensitive strategic areas of the Soviet Union is one that the marshal and his subordinates simply cannot accept. By definition, it had to be a spy plane.

If this assumption is correct, it was irrelevant for the Soviet commanders whether the "intruder plane" was a military plane or a civilian one with hundreds of passengers on board.

For form's sake, Ogarkov insisted that it had been impossible to identify it positively because of cloudy nighttime conditions. But he also implied that the decision to shoot it down was justified, no matter what kind of plane it was.

Asked if the fact that a relatively low-level commander had ordered the shooting down of the jumbo jet implied that the Soviet Union could find itself engaged in a nuclear war without the Kremlin knowing, Ogarkov replied angrily that the situations were not comparable.

Under the Soviet border law, local military units have wide powers to shoot first and ask questions later in the event of cross-border intrusions.

If the actual shooting down of the airliner was treated as a purely military affair by the Soviets, it rapidly became a problem for the civilian politicians once the United States started releasing information and stirring up world opinion. In the view of many Western analysts here, the Kremlin could then have succeeded in limiting most of the damage had it promptly acknowledged that an error had been made, offered to pay compensation to relatives of the victims and promised to ensure that nothing similar would ever happen again.

The Soviets would still have been able to save face by attributing the mistake to the extraordinary behavior of the South Korean plane and constant "provocations" by U.S. reconnaissance flights along their borders.

It is impossible to tell whether Soviet leaders even considered such an approach. If they did, they appear to have rejected it fairly rapidly for reasons that once again stem both from the national psyche and the division of authority between soldiers and civilians.

A Western diplomat here with long experience of the Soviet Union based a hunch early in the crisis, that the Russians would attempt to brazen it out, on what he called "the logic of a collective mentality."

"It is almost impossible for a society that puts so much emphasis on collective values to admit that a mistake has been made," he said. "This is first and foremost a Russian trait rather than a specifically Communist one. It is also very difficult for individuals to oppose the values of the collective, which is why the rare ones who do feel such a sense of liberation."

To this psychological explanation must be added the tacit agreement that exists between civilian leaders and the military. Traditionally, the Army does not interfere in civilian affairs as long as it is given the resources it needs and is allowed to get on with the task of defending the country. A politician like Andropov, who is reported to have owed his promotion to the backing of the military, would have great difficulty overruling the decision of one of his commanders in the national security field.

What this means in effect is that the leadership's broad political objectives may occasionally have to take second place to narrow military interests.

As an example, Western diplomats here cite the persistent forays by Soviet submarines into Swedish waters despite the obvious damage this did to the Soviet Union's peace-loving image with Scandinavian pacifists. The intrusions are continuing even though they are clearly politically counterproductive.

"I don't think we are heading for a Bonapartist situation in the Soviet Union where you have the military taking over power as it did in Poland," a Western diplomat here said. "Soviet-style communism doesn't work that way. What is true, however, is that the military is a powerful pressure group and is granted considerable autonomy in what are perceived as strictly security matters."

Despite the inability of the politicians to admit error, it was, nevertheless, possible during the past week to observe the Kremlin attempting to respond to international pressures.

Little by little, more information about the fate of KAL Flight 007 was revealed until finally the Soviets acknowledged that they had shot it down. At first this confession was couched in what an American official here described as "a euphemism that will go down in history: an order to stop the flight was 'fulfilled.' " By yesterday, however, Ogarkov admitted that a Su15 interceptor downed the plane with two air-to-air missiles.

Moscow also attempted to seize the propaganda initiative away from the Reagan administration by telling the world its version of what had happened.

The decision to allow Ogarkov to be cross-examined by western journalists bears the personal imprint of Andropov, who has adopted a slightly more open style of government since coming to power in November last year. The Soviet press, for example, now carries lengthy reports of sessions of the ruling Politburo which were formerly held without any public announcement at all.

It is impossible to know to what extent Andropov shares the obsession of his generals with security--even when this so obviously conflicts with other objectives--and to what extent he is obliged to go along with them because of the domestic balance of power. Either way, the room for maneuver of a Soviet leader is severely limited by domestic considerations.

As one western analyst remarked: "Andropov's input into this crisis so far has been one of style rather than of substance. The Russians have reacted in a very similar way to the way they would have behaved 10, 20 or even 200 years ago to what they perceived as a hostile intruder in their territory."