Capt. Thomas Roken stepped from the cockpit of his Viggen jet at the Swedish Air Force base at Norrkoping after a night patrol looking for Soviet submarines. As infrared film from the Viggen's cameras was being developed, Captain Roken summed up the anomalies of being part of a policy of armed neutrality.
''Sometimes up there,'' he said, gesturing into the cold, star-filled night sky over the Baltic, ''we meet planes from the Warsaw Pact countries, other times we encounter NATO planes.
''We usually say hello to one another - tilt our wings - and then go our separate ways. There is a spirit of comradeship that crosses cold war borderlines.''
It is this spirit of comradeship that will never be quite the same after the extraordinary affair of the 10-day ''capture'' of Soviet Submarine 137.
That the Whiskey-class submarine sent to spy on them by their superpower neighbor probably had nuclear weapons aboard has pushed this small, neutral country into a drastic and painful reevaluation of foreign and defense policies.
Soviet credibility in promotion of the plan for a nuclear-weapon-free zone in the Nordic area has been taken a beating. Swedish Foreign Minister Ola Ullsten said Soviet references to the Baltic as ''a sea of peace'' were no longer valid. Swedes are likely to be far more circumspect in their dealings with the Kremlin in the future.
As an immediate result of the submarine affair Swedish diplomats in Moscow boycotted the Nov. 7 celebrations of the Bolshevik Revolution and Swedish communists demonstrated outside the Soviet Embassy in Stockholm.
On the defense front a hitherto unfamiliar jingoistic mood spread as a new concept gained political respectability. It was the need for ''hojd beredskap'' (heightened preparedness).
Previous calls for ''hojd beredskap'' had been the prerogative of the armed forces, notably supreme commander Gen. Lannart Ljung. The appeals have fallen on deaf political ears until now. In the wake of Submarine 137, the credibility of General Ljung has taken on an almost pre-World War II Churchillian dimension.
Talk of cutting defense budgets to ease Sweden's present economic crisis is suddenly passe, verging on the unpatriotic. Swedes who laughed at talk of ''the window of vulnerability'' on a recent visit by US Defense Secretary Caspar Weinberger are no longer laughing.
Not that anyone is seriously suggesting that Sweden apply for NATO membership. The submarine incident has been counterbalanced in Swedish opinion by the latest outbreak of nuclear saber-rattling in Washington.
But as one example of the changing mood in Sweden, Gunnar Bjork, mild-mannered Center Party member of parliament who heads a committee investigating defense spending, now admits that protection against submarine incursions into Swedish waters must be stepped up.
Previously almost annual Navy sightings of ''unidentified'' subs in Swedish waters were dismissed as specially staged PR exercises aimed at increasing the Navy's slice of the defense cake. No one took them seriously.
Now all that has changed. The Navy is currently staging a highly successful recruitment program under the slogan ''Whiskey on the rocks - it's something we don't want. Join the Swedish Navy.'' It is also, without doubt, going to get the extra cash it needs for ''hojd beredskap.''
Before the voyage of the Submarine 137, antisubmarine defense was left largely to land-based radar stations and air patrols. The Navy has for a long time said that this is not enough and has stressed the need for ships equipped with advanced sonar detection systems.