The Rogers commission -- the Presidential Commission on the Space Shuttle Challenger Accident -- has served the country well. Recall what you knew and thought about NASA and the space program before the accident. Compare that with what is known now. What looked like a superachieving agency that never made a serious mistake turns out to have been quite different. Much of that transformation in view is owed to Chairman Rogers and those who served with him. Their report is authoritative.

sk,3 From telemetry and photography, from testimony, from the wreckage painstakingly brought up from the ocean floor, the commission was able to identify beyond doubt the exact flawed part that brought down the Challenger -- a leaking O-ring -- and to rule out all other causes. It showed that O-rings had been recognized as a problem of potentially fatal proportions from the earliest days of the shuttle's design -- the first memos in the files date from 1977. For the first nine shuttle flights the problem did not show up in serious form. "Beginning with the 10th mission, however," in January 1984, "and concluding with the 25th, the Challenger flight, more than half of the missions experienced field joint O-ring blow-by or erosion of some kind."

For various reasons, NASA wasn't monitoring such trends. Out of both budgetary considerations (more flights meant more revenues) and pride, it had set itself an ambitious launch schedule that stretched it too thin. The safety program was submerged just when it should have been strengthened. The agency's own "launch constraints" arising out of the O-ring problem were repeatedly waived.

It was in this institutional setting that the decision to launch Challenger was made on the morning of Jan. 28. Engineers from solid rocket manufacturer Morton-Thiokol had said it was too cold to launch; they feared the cold weather would further weaken the O-rings. They were overruled by middle-level NASA officials who would not brook delay and by higher-level Thiokol officials who, the commission said, were trying to propitiate "a major customer." Higher-level NASA officials went uninformed.

The report recommends predictable steps -- rethinking of the rocket design, "a flight rate . . . consistent with . . . resources," a strengthened safety program and an end to the "management isolation" at Marshall Space Flight Center, where a lot of the problem occurred

sk,3 Some traditional cheerleaders for the space program, particularly in Congress, greeted the commission's recommendations almost with euphoria. Good report; time now to get back to business, they said. James Fletcher, the returned NASA administrator, with whom we have had our differences, said it better. In pledging the necessary improvements, he warned his subordinates: "We have been the object of America's respect for a long time. We cannot take this respect for granted in today's environment." NASA has to earn its way back.