THE CBS EVENING NEWS might have opened this way on the night of Jan. 27: "Caution was the watchword at Cape Canaveral today, as take-no-risk NASA officials decided once again to postpone a launch rather than endanger the crew, which includes school teacher Christa McAuliffe. Bruce Hall in Florida has a report on how NASA is standing firm despite the pressure of a tight launch schedule."

Instead, Dan Rather began his newscast on the eve of the shuttle tragedy this way: "Yet another costly, red-faces-all-around space-shuttle-launch delay. This time a bad bolt on a hatch and a bad-weather bolt from the blue are being blamed. What's more, a rescheduled launch for tomorrow doesn't look good either. Bruce Hall has the latest on today's high-tech low comedy."

Hall reported from Kennedy Space Center that "confidence in NASA's ability to maintain a launch schedule has been rocked by this series of embarrassing technical snafus and weather delays."

He went on to narrate the cause of the latest delay, a door handle that didn't work. Pictures of frustrated technicians in white suits accompanied a narrative of failure: a screw that was stuck, batteries that were too weak to operate a drill, a drill bit that crumbled, and finally, the use of a hacksaw. The piece conveyed the impression that NASA technicians, though prudent and cautious, were bumblers.

The tone of media coverage of NASA on the night of Jan. 27 matters because it may help explain the central mystery of the shuttle tragedy: Why did NASA decide to launch the Challenger the next morning despite extremely cold weather and warnings about O-ring problems? Were therehidden pressures? A White House phone call, perhaps? Or a push from an ambitious NASA manager?

A senior NASA official advanced a theory of his own several weeks ago. He blamed the news media. In an interview with The Washington Post, Richard G. Smith, director of the Kennedy Space Center, argued that news stories about delays and aborted launches in the weeks before the Challenger launch had created "98 percent of the pressure" to go ahead with the ill-fated mission.

Smith explained: "Every time there was a delay, the press would say, 'Look, there's another delay. . . here's a bunch of idiots who can't even handle a launch schedule. . . . You think that doesn't have an impact? If you think it doesn't, you're stupid."

Smith was roundly denounced for his remarks. "NASA's attacks infuriate the presidential investigating panel," reported The Wall Street Journal, noting that one member of the Rogers Commission had complained "of a NASA 'counterattack.'" A letter to The Washington Post chided the "Nixon-like outburst by NASA's Richard Smith pillorying the news media. . . ."

But Smith had a point, and one that deserves to be taken seriously by a profession that has held up a magnifying glass to everything surrounding the shuttle disaster but its own performance.

The news media probably did put pressure on NASA's managers to launch Challenger. Not "98 percent of the pressure," certainly, but some of it. And it's the sort of subtle pressure that journalists tend to overlook when they are digging for the causes of a tragedy like the Challenger explosion.

A survey of newspaper and television coverage of NASA in the weeks before the Challenger launch shows a series of increasingly critical stories focusing on NASA's delays. At that time, the "problem" at NASA that troubled the media wasn't that the space agency was too gung-ho and launch-happy (as some post-Challenger reporting has suggested) but that it kept postponing launches and wasn't meeting its schedule.

The previous shuttle flight, the Columbia, had been scrubbed seven times before it was finally launched Jan. 12, and the Challenger launch had been postponed three times. But instead of winning media praise for its prudent safety procedures, the space agency received a series of put-downs.

NASA's problems were mostly its own fault. The biggest pressure to launch Challenger was the space agency's own unrealistic schedule, which called for an 15 shuttle launches during 1986. In retrospect, it's clear that NASA was pushing too hard. But the news media, rather than urging caution, seemed during January 1986 to be egging NASA on. News reports repeatedly stressed the importance of meeting the schedule.

The media's tone became downright snide on Jan. 27, when the long-awaited launch of the "teacher in space" was aborted because of equipment problems and bad weather. The CBS story, cited above, set the tone by characterizing the scrubbed Challenger launch as a "comedy of errors." Other networks and newspapers adopted a similar tone.

The New York Times agreed that the scrubbed launch had been "a comedy of errors." The NBC Nightly News described the bolt problem as "an exasperating mishap" and "still another delay in efforts to put the first schoolteacher in space." On ABC's World News Tonight, John Quinones reported: "Once again a flawless liftoff proved to be too much of a challenge for the Challenger. This time the delay was blamed on bad weather and a stubborn door handle." (ABC, like CBS, used the word "blamed" to characterize NASA's explanation.)

The Washington Post led its story on the aborted Jan. 27 launch with a parody of an old proverb. The story began: "For lack of horsepower, the drill would not work; for want of a drill, the bolt was stuck; for want of the bolt, the hatch handle would not budge and, while technicians awaited another drill and tried a hacksaw, an Arctic cold front blew away the good weather."

The networks and newspapers all noted that the freezing weather expected on Jan. 28 might cause problems for the rescheduled launch. But both CBS and NBC pointed out that NASA's weather forecasts had been wrong in recent days and that these erroneous weather forecasts had led NASA managers to postpone launches unncessarily. CBS said of the overly-cautious forecasting: "NASA admitted they goofed."

The Jan. 27 stories capped more than a month of critical coverage of NASA delays and bumbling. For NASA, it was a month of rising frustration, as the shuttle Columbia went through seven scrubbed launches before it finally lifted off on Jan. 12. For the media, the Columbia launch became a kind of running soap opera.

Here's the way Dan Rather reported one aborted launch, on Jan. 10: "The star-crossed space shuttle Columbia stood ready for launch again today and once again the launch was scrubbed. Heavy rain was the cause this time. The launch has been postponed so often since its original date, December 18, that it's now known as mission impossible . . . ."

Tom Brokaw on NBC reported another of the Columbia postponements, on Jan. 7, this way: "At Cape Canaveral today, mission commander Robert Gibson said: 'We have a bad habit going here,' a habit of delays . . . . This time, the weather was bad at the Cape and two emergency landing sites. NASA decided the launch would be too risky. It's now aiming for Thursday of this week. These delays are becoming expensive as well. A NASA official said today that the agency loses as much as $300,000 every time there's a postponement. That's how much it cost to gear up again for the next time."

Brokaw reported the next day, on Jan. 8: "It's now 0-for-5 for the shuttle Columbia." And on Jan. 10: "By now the shuttle Columbia's crew members are experts at getting in and out of their spacecraft. They're 0-for-6."

Peter Jennings concluded on ABC after the Jan. 10 postponement: "The space agency hasn't had such problems since the days of the Mercury program . . . ."

Now imagine, for a moment, that you are a senior NASA official on the morning of Jan. 28. Because you are publicity conscious -- indeed, because you may well be a publicity hound -- you have been watching all three network newscasts for the past month and reading all the major newspapers.

What goes through your mind as you listen to arguments from meteorologists and technicians about cold weather and O-rings? Do you look for reasons to avoid more of the delays that have "rocked confidence" in NASA? Do you preview in your mind, if only for an instant, what Keystone Cops footage the networks will show tonight after another aborted launch? Do you worry about extending the "comedy of errors" by postponing the Challenger launch yet another day?

NASA officials, of course, should be immune from such petty anxieties and pressures. They should have the strength of character to ignore what the news media -- or anyone else -- have to say about launching a spacecraft. They should ignore public opinion. Above all, they should ignore what newspaper and television commentators have to say about scrubbed launches.

That raises a central problem about NASA: the possibility that it was too publicity conscious. If Richard Smith of the Kennedy Space Center is right in saying that the news media created "98 percent of the pressure" to launch Challenger, then that means NASA was taking news-media coverage too seriously. Officials were spending too much time watching television and reading newspaper clips.

NASA's over-attention to its media image has always been part of the hubris of the space agency. The early space launches, after all, seemed to run on two parts Life magazine, one part liquid fuel. Having benefited from favorable media coverage for so long, NASA officials undoubtedly were upset in January by stories that made them look like idiots.

The Challenger saga also illustrates a wider problem for the news business, one that surfaces in the coverage of other stories, from terrorist hijackings to political campaigns. The act of describing an event influences its outcome. Terrorists in Beirut stage gun battles for television cameramen; American politicians adjust their campaign schedules, and sometimes their political programs, to suit journalistic appetites; space-agency officials court favorable coverage.

In the news business, we like to think of our role as neutral, and to imagine that we do no more than hold up a mirror to the world. But it's more like a magnifying glass. Under the magnifying glass, small mistakes can seem enormous, simple human failings can seem monstrous, decisions that at the time looked sensible can appear grossly negligent. Indeed, media coverage can sometimes focus the light so sharply that it burns a hole right through the subject of the story.

It is the nature of the news business to analyse events with absolute certainty, and then to reverse itself and see things quite differently, again with absolute certainty. This process takes no more than an instant, no longer than the time it takes a rocket to explode.

Here's the way NBC's "Today" show on the morning of Jan. 28 reported the imminent launch of the Challenger on its 7:00 a.m. newscast:

Bob Jamieson, anchor: "At Cape Canaveral, NASA will try again this morning to launch the space shuttle Challenger. This will be the fourth attempt for this mission, which includes a trip into space for school teacher Christa McAuliffe. Monday's attempt was scrubbed by trouble with a door handle. Steve Delaney is at Cape Canaveral this morning. Good morning, Steve."

"Good morning, Bob. It is cold here; it is long-john weather at the Cape. NASA has had launches in subfreezing weather before, but never from the shuttle program, and there is some concern about the effect of these cold temperatures. Primarily, they're looking at a buildup of ice on the outside of the external fuel tank, which is loaded with hydrogen and oxygen at very low temperatures . . . .

"So, a lot of people around the country are going to be watching this one, if it gets off today, as they sincerely hope it does, because the longer they delay it the more they throw the whole schedule for the year off, and it's already a bit behind . . . ."

The Challenger disaster will torment NASA for years to come. It should also teach the news business an important lesson.

The lesson isn't that the news media should have been nicer to NASA, but that they should have been tougher. Reporters should have been asking hard questions about the shuttle program, its technical systems, its overly ambitious launch schedule and a NASA bureaucracy that among other things was overly concerned with its public image. Rather than hectoring NASA for missing its schedules, the media should have questioned whether the shuttle should have been launched at all on that sad January morning.