Bit by horrifying bit the Rogers commission, with no little help from reports in the media, is pulling the story of the Challenger disaster out of the space agency and its contractors. The end is not yet clear, but enough is so far known to stir the most serious misgivings among a public that had come rather casually to trust both the competence and the candor of the manned-flight establishment.

In terms of what happened on that dreadful day one month ago, the most terrible disclosure is that NASA failed to act on two sorts of information that, one would think, would have galvanized all those anywhere near the shuttle program. For several years NASA had received expert warnings that the seals on the rocket boosters were troublesome -- and a failing seal was everywhere understood to be the ticket to disaster.

Then, on the eve of the flight the managers of Morton Thiokol Inc., the booster contractor, acting on the unanimous and impassioned advice of company engineers, recommended against a launch on grounds of the unprecedented cold expected at Cape Canaveral. Some hours later, after lengthy consultations with NASA, Morton Thiokol withdrew its objections, and the flight went ahead, and Challenger exploded -- apparently because of a failure of a booster seal.

The contractors are saying essentially that it wasn't their fault: either they passed on their reservations faithfully or were pressured by a launch-happy NASA to quash them. NASA is also saying essentially that it wasn't its fault: It didn't get a clear-cut no-launch word from a contractor and in any event it did no quashing. The argument is getting increasingly fine and semantical, but a few things about it are clear.

Not only NASA but the contractors -- Rockwell International Corp. as well as Morton Thiokol -- appear to be extremely reluctant witnesses. This is exercising chairman William P. Rogers and others on the presidential investigating commission, and it is costing all of the witnesses substantially in public confidence.

NASA, a public agency, is looking especially bad. If it is found to be engaging in a cover-up, that is one thing. Otherwise, it is being revealed as a deeply flawed organization, one that in its pursuit of other program goals had lost its grip on the first priority of mission safety and one that lacked reliable ways of getting crucial information to decision makers. All this talk about NASA's can-do spirit and about the need to get on with the program had better be set aside until fundamental questions about the agency's fiber and leadership are answered.