While the redesigned space shuttle orbits the earth, NASA is celebrating 30 years of discovery.The National Aeronautics and Space Administration is 30 years old this weekend. On Monday, the orbiter Discovery will land after the first space shuttle flight in nearly three years.

Yet all who see Discovery's flight as a reaffirmation of America's ability to do things right agree that the United States must establish a long-term space policy to prevent what is called the tortoise-and-the-hare syndrome of space exploration.

"The problem that has always plagued the American space program is that we're the tortoise and the hare with the Russians," said Don Lind, a shuttle astronaut who now is a Utah State University physics professor.

"We find ourselves significantly behind. Now we'll make a big burst of speed, and we'll probably catch up, and then we'll go in the doldrums again," Lind said. "The thing I hope is that we'll get out of the tortoise-and-the-hare situation (and) get some long-range plans."

But that lag, followed by investment of a tremendous amount of energy and money in a goal, is the way NASA has operated from the beginning.

"That was part of the problem," said Bob Hotz, a former Aviation Week editor. Hotz was part of the Rogers Commission that investigated the Challenger disaster, which put the United States out of the space program for 21/2 years.

"We got into the space program as a reaction to the Russians," Hotz said while covering the Discovery launch. "We've never had a real space policy."

The Soviets launched Sputnik, the world's first satellite, on Oct. 4, 1957. On Oct. 1, 1958, NASA was born.

"We never decided what we wanted to do in space," said Hotz, who contends NASA's reluctance to give up any ground exacerbated the problem of direction.

"Space is place where you can do things you can't do on Earth," the aerospace expert said. "It's a place to work. NASA thinks of this as spectacular. And that's not the case."

What is spectacular is what NASA wants to accomplish, including exploration of the planet Mars, another lofty goal for the future.

"To me the most important thing is to have a continuing plan not peaks and valleys in goals," said J.R. Thompson, director of NASA's Marshall Space Flight Center. "We ought to be in it for the long haul.

"I don't worry how much we're going to launch in the next six months. I look at how much we're going to launch in the next six years," Thompson said after Discovery's successful flight. "There's no question about it that success in the launches breeds success in funding."

The peculiarities of NASA funding are evident in the yo-yolike levels each Congress sets for the national space agency.

"If we could get some long-term financial stability," Lind said, "little programs, big programs, I don't care what it is as long as it's stable so that you could plan on what's going to be available 10 years from now."

Ten years from now, NASA must have an operational manned space station, President Reagan ordered in his 1984 State of the Union address. Reagan has chosen "Freedom" as the space station's name.

"Space Station Freedom will be the key to our future in space," NASA Administrator James Fletcher said in a recent address. "Together with our friends and allies in Europe, Canada and Japan, we will develop it into a fully equipped scientific laboratory where people will work 'round the clock to do essential experiments in the life sciences and materials sciences that could, one day, permit us to send humans back to the moon or to explore Mars."

The manned space station was first proposed by NASA in the late 1960s, during the days of Apollo and moon landings. Enter the shuttle, the space transportation system. But NASA oversold the space shuttle, which would ferry workers and materials to the space station, to get presidential support.

"When the shuttle was in the design stage, the estimates on what the costs of orbits were going to be were not coming out right," Lind said. "And so they tried to lower the cost per flight by directing all traffic onto the shuttle."

The Challenger explosion, and the revelation that high-level officials with contractor Morton Thiokol ignored concerns about safety, caused rethinking of the pressure to launch to make the shuttle more cost-efficient. And the disaster grounded U.S. satellite placement for nearly three years while NASA, the sole source of launches, was revamped.

"So the position of the shuttle has changed. Rather than being the only launch vehicle for the entire United States, both civilian and military, it is now recognized that it's got to be part of a mixed fleet of various boosters," Lind said.

One booster of various agencies in space exploration is Reagan, who in 1984 allowed the Air Force to buy Titan missiles to launch defense satellites. Reagan also endorsed commercial satellites in space.

But Holz maintains NASA does not want to share space with other outfits launching communications satellites, known as comsats.

"If NASA had maintained control of comsats, we'd still have underwater cables," he said. "NASA should go back to being a research and development outfit."

But where America's space program leads, either in research or in development, is a matter of national priority, said Thompson.

"I'm a little bit disappointed the space program doesn't come across more in the national debates. That's where the leadership starts," he said. Where NASA ends up is "going to rest predominantly with the leadership of this country."

But Hotz, who said he "was covering space before there was a NASA," pooh-poohed the notion presidents should decide where the agency should go in terms of goals.

"They say, `The White House ought to give us direction. The president ought to give us direction.' They're crybabies. They're living off Apollo," Hotz said. "It's an aging agency. They aren't attracting any young people."

NASA now is analyzing the goals outlined by the presidentially appointed National Commission on Space, whose 1987 report outlined where the country's space program should lead.

The three major goals are advancing knowledge of Earth, the solar system and the universe, exploring, prospecting and settling the solar system, and stimulating space enterprises for the direct benefit of people on earth.

Hotz, a member of that commission, maintains that accomplishing the enterprise goal should increase opportunities for civilian space exploration rather than rely solely on NASA for conquering the frontier.

"They can't do it and shouldn't do it. There are too many diverse things to do out there," he said. "Space is here to stay. It's there for anyone who wants to use it."