BEHIND THE flap over the story about the next space shuttle mission lies a delicate and wary experiment in civilian-military relations. From the beginning of the American space program, the military role was central: it controlled the rockets and had good use for the projectiles shot into space. President Eisenhower, however, set up a civilian agency, NASA, to run the manned space program. The Pentagon's own manned space effort, the Manned Orbital Laboratory, was aborted in 1969 with the understanding that in time Defense would use NASA's shuttle. Once the shuttle was perfected, and once the military started running out of the ready Jupiter rockets it had long used to put its gear into space, the Pentagon got in line.

NASA, after a shadowy start, had blossomed under James Webb's leadership into a marvelously open agency: the openness was meant to demonstrate peaceful, progress-minded purpose and to distinguish the trust-building character of American society from the suspicion-inducing nature of the closed Soviet society. But the openness could not be sustained once the Pentagon began using the shuttle for its necessary intelligence missions. No one had demanded full public disclosure of the military's unmanned rocket program. To perform no less sensitive missions from a manned vehicle would, plainly, require new information rules. NASA and the Air Force fought it out, and the agreed rules were announced last Monday, on NASA turf, by the Air Force.

Here it is important to note that plenty of military people were leery of having to run a sensitive intelligence mission out of an open civilian agency. Tension is inherent in the different missions and cultures of the two branches. Personal and institutional frictions were bound to complicate their effort to "dock" aboard the shuttle. So it is that leaks about the Jan. 23 flight are being taken by some military people as proof of the unwisdom of the whole joint venture. Others have insinuated that the military did the leaking -- to discredit the venture and to create the justification for a new and separate military manned space program.

NASA and the Air Force may have been uneasy riders of the same shuttle. Still, they did agree, however uncomfortably, on an initial set of information rules. Suppose the general who announced them last Monday had not added that news organizations that even speculated about the nature of the military payload might be investigated. That absurd, intrusive suggestion committed the Pentagon to overreact, as it did, when this newspaper published its story bringing Post readers up to date on information that had been published elsewhere and that had been conscientiously vetted for national security considerations.

The rest, as they say, is journalism. The history of military-civilian collaboration on space flight, meanwhile, is still being written.