Flawless Landing Caps Discovery’s Mission : Space: The shuttle touches down in the Mojave Desert after deploying an ambitious solar probe and restoring NASA spirits.

With its solar probe safely on its way, the space shuttle Discovery was kissed by the rising sun as it dropped out of a clear sky and glided to a flawless landing here Wednesday morning. It was a cold (38 degrees), crisp moment when the shuttle touched down at 6:57 a.m, but the successful mission warmed the hearts of space officials who feel they have been snakebitten several times in recent months.

“It’s been a long, hot summer,” said veteran astronaut Robert Crippen, now head of the shuttle program. The Discovery’s mission was short, but oh so sweet, to the National Aeronautics and Space Administration, ending a five-month drought caused by various problems with the shuttle fleet.

“They did this one right,” Crippen said of his NASA colleagues during a press conference after the landing. And in a not too subtle jab at pundits who “criticize our mistakes,” Crippen said: “You must also acknowledge our success, and Discovery was a success.”

The sun had just begun to peek over the Leuhman Ridge east of this sprawling base when the Discovery made a sweeping left turn and banked toward the Mojave Desert floor. The sun glistened off the shuttle’s belly as if to hail the primary goal of the four-day mission--the deployment of the robotic spacecraft Ulysses on the most ambitious solar expedition ever attempted.

Ulysses was released from the shuttle’s payload bay just six hours after Saturday’s launch from the Kennedy Space Center in Florida. A triple-stage rocket system then sent the European-built robot rushing away from Earth orbit at more than 34,000 m.p.h., faster than any other spacecraft has ever left the planet.

Ulysses will journey all the way to Jupiter, where it will use that planet’s gravity to accelerate into an orbit that will carry it over the poles of the sun. As it rounds Jupiter, Ulysses will reach a speed of nearly 90,000 m.p.h., faster than any other man-made object has ever traveled.

As far as is known at this point, Ulysses is in perfect health, said Roger Bonnet, chief scientist with the European Space Agency, NASA’s partner on the mission.

“It will take three or four weeks to check all the experiments,” Bonnet said. “But there was no damage from the launch.” Ulysses carries nine instruments capable of 11 experiments, and the first results could come in about two weeks, Bonnet said. That will involve a study of interstellar gas traveling through the solar system.

Ulysses’ instruments will study the solar system as the spacecraft travels on its long course to the sun. It will reach the sun’s south pole in 1994 and then loop up over the sun and pass over the north pole in 1995.

This will be the first major effort to study the sun’s polar regions, and scientists hope the results will tell them much about the dynamics of the sun. The poles are important because only the mid-latitudes of the sun can be studied from the Earth, and scientists believe many events, such as sunspots and solar flares, are influenced by whatever happens at the poles.

But the necessity of using Jupiter as a slingshot to fling itself into a solar polar orbit means Ulysses has a long journey ahead. It will travel more than 2 billion miles before its mission is completed, and it will never be closer to the sun than it was while still on Earth.

The Discovery completed its mission of four days, two hours and 10 minutes with no significant problems, and Crippen said it appeared to be in nearly perfect shape after a brief inspection on the landing strip.

During the mission, Discovery commander Richard N. Richards, 44, a Navy captain, and his all-military crew carried out a number of routine experiments.

Marine Lt. Col. Robert D. Cabana, 41, the Discovery’s pilot, brought the big glider in over the coast near Santa Barbara, and the twin sonic booms were heard throughout much of that area. There were few spectators here to see the landing, however. NASA said only 5,250 people watched the landing from the public viewing area on the east shore of the dry lake bed.

That was the third-smallest crowd for a public landing in the history of the shuttle program. There is no public viewing area for Defense Department launches.

Although space officials hailed the flight as a triumph and a sign that at least some of NASA’s problems may be behind it, there are still some trouble spots ahead for the space agency. Crippen said it is still not known what caused a leak in the hydrogen fuel system in the Columbia, further postponing a much-delayed astronomy mission.

And Crippen said that although the hydrogen leak aboard the shuttle Atlantis has been fixed, he was so unsure of the status of the next flight that he declined to put a date on it. He did say, however, that he expects Atlantis to fly sometime in November on a secret military mission.

This was the first flight for a member of the U.S. Coast Guard. He is Cmdr. Bruce E. Melnick, 40. The other crewmen were Navy Capt. William M. Shepherd, 41, and Air Force Maj. Thomas D. Akers, 39.