If Morton Thiokol and NASA officials were looking for an omen Tuesday morning, they needed only look up.

Whereas Mother Nature hasn't always cooperated with many of their previous attempts to test fire the redesigned space-shuttle booster, the sky Tuesday was a beautiful blue with only a trace of wispy clouds.And by all appearances, when it came time to conduct the fourth full-scale test of the booster several hours later, events unfolded just as beautifully.

"It's still too early to tell from the data, but it was sure a good-looking test," beamed J.R. Thompson, director of the Marshall Space Flight Center in Huntsville, Ala.

Moments earlier, Thompson was nervously checking his watch as he watched the 120-second-long test from a special VIP viewing area 6,000 feet away from Morton Thiokol's new state-of-the-art test facility.

The giant horizontal rocket sent a spectacular 500-foot-long flame from its nozzle, charring a wide swath of sagebrush and belching a massive cloud of grayish-brown smoke. Some of the sagebrush continued to burn 20 minutes after the test.

As the display ended, Thompson let out an emphatic, "Yea," and thrust his clenched fist into the air, much as a winning pitcher after recording the final out.

"It's always the start of a good day when a booster fires the whole two minutes. This one looked as good as the last one," Thompson said.

Optimism remained the byword during a short post-test debriefing a little more than an hour later.

"And one to go," said Royce Mitchell, solid-rocket manager for Marshall, referring to next month's final scheduled static test of the redesigned booster before the space shuttle Discovery flies in August. It will be the first time American astronauts will be carried into space since the Challenger disaster Jan. 28, 1986.

"This one worked very well. It's a good feeling to have everything look so well at this stage of the firing," Mitchell said, noting final judgment can't be passed until the booster is pulled apart and examined.

Allan McDonald, Morton Thiokol vice president of shuttle engineering, sang the same refrain.

"I'm certainly pleased with what I've seen," McDonald said. "I just hope it looks as good inside as out."

McDonald said the importance of Tuesday's test, the first conducted in Morton Thiokol's new test bay, cannot be emphasized enough because it's the first to simulate hydraulically the immense pressures Discovery will experience during ignition and later about one minute into flight - loads that can range as high as 330,000 pounds per square inch.

Investigators found these pressures corresponded with the puff of black smoke and the later appearance of a flame revealed during replays of the Challenger accident and were thought to have played a role in the tragedy itself.

Initial data from Tuesday's test, however, suggests these pressures were not a factor, Mitchell said.

McDonald said Tuesday's test was also significant because it marked the first time the booster and its propellant had been warmed in excess of highest temperatures that will ever be encountered during flight preparation at Cape Canaveral - even during the hottest summer days.

Thompson said if the test data and inspection of the booster hardware show the test was as successful as it looked from afar, then most of the question marks surrounding the redesign will be gone.

"We've got a good chance for an August launch," Thompson said.

Mitchell concurred, but hedged on a precise date.

"It's August . . . by the 31st . . . but that's being optimistic. A lot has to go right."

Then he reminded everyone that the task is still unfinished.

"I'm anxious to go, but I'm also anxious to make sure we're ready to go," he said. "And we've still got to test them all."