Limits on Manned Space Flights Urged : Shuttle: A White House panel recommends development of robot vehicles. It says the odds make another fatal launch disaster likely.

Warning that another space shuttle disaster is likely in the next several years, a White House panel Monday recommended swift development of an alternative launch vehicle and stringent new limits on manned flights to reduce the risk to human life.

The experts’ report said the National Aeronautics and Space Administration is counting too much on the shuttle, the centerpiece of the U.S. space program, despite the fact that it is too expensive, too risky and not necessary for many goals of space exploration.

The shuttle should be launched, the panel of experts concluded, only when human involvement is essential, and NASA should spend several billion dollars to develop an unmanned launch vehicle.

With the aid of hindsight, the panel said, it was inappropriate to send seven crew members on the Challenger mission in 1986. All seven were killed when the shuttle exploded shortly after blastoff.

NASA Director Richard H. Truly, responding to the recommendations of the 12-member Advisory Committee on the Future of the U.S. Space Program, said he would take the recommendations seriously. But he added: “You can’t have a risk-free space program. It’s a risky business. We’re not taking undue risk with human life.”

The committee resisted calls for a radical restructuring of NASA, but it said the agency has been “trying to do too much,” given the time and money available.

“America’s civil space program is at a crossroads,” said committee Chairman Norman Augustine, chief executive officer of Martin Marietta Corp. “NASA is neither as troubled as some would suggest, but not nearly as good as it will have to be to carry out the kind of space program that we recommend.”

The committee said it recognized that the United States must depend on the space shuttle through the end of the century. However, it strongly urged the space agency to improve the shuttle’s reliability while using it only when essential to put humans into orbit.

“The statistical evidence indicates that we are likely to lose another space shuttle in the next several years,” the panel said in its unanimous report. “This would seem to be the weak link of the civil space program--unpleasant to recognize, involving all the uncertainties of statistics, and difficult to resolve.”

Augustine put it more bluntly at a news conference.

“It would not be at all surprising to us that we would lose at least another shuttle before the space station is in orbit,” Augustine said. “Because of that, I think we need to prepare ourselves both emotionally and in terms of hardware and infrastructure.”

He added that the panel was concerned “that the space shuttle may be the thin reed that supports our entire civilian space program.”

The review was prompted in part by the embarrassing defects in the long-awaited Hubble Space Telescope. The panel, appointed by Vice President Dan Quayle, made wide-ranging recommendations for a future space program:

--Major emphasis on basic scientific research, including missions to take environmental measurements, a longer-range mission to put astronauts on Mars and the development of a modified space station to serve as a life-science laboratory and a base for planetary travel.

--Development of a heavy-lift launch vehicle that could take over much of the cargo delivery work now scheduled to be done by the space shuttle when work starts on the space station in 1995.

--A major overhaul of the design of the space station to reduce its cost and complexity, taking all the time needed to do the job right.

--Increased funding for the agency at the rate of 10% more than inflation each year.

--A plan to exclude some NASA employees from federal Civil Service hiring, firing and pay limits to give the agency greater flexibility in recruiting and retaining top rocket scientists and other space specialists.

--A number of management changes, including changing how NASA operates its centers around the country in order to avoid counterproductive competition.

In its discussion of the shuttle, the committee said the spacecraft would be absolutely essential to the U.S. space program for the next decade or more.

“The space shuttle differs in important ways from unmanned vehicles,” the report said. “On the positive side, it provides the flexibility and capability attendant to human presence, and it permits the recovery of costly launch vehicle hardware.

“On the negative side, it tends to be complex, with relatively limited margins; it has not realized the promised cost savings, and should it fail catastrophically, it takes with it a substantial portion of the nation’s future manned launch capability and, potentially, several human lives.”

While limiting future manned flights to missions that must have a human presence, the experts said, the agency also must “take those steps needed to enhance the shuttle’s reliability, minimize wear and tear, and enhance launch schedule predictability.”

“We further conclude that NASA should proceed immediately to phase some of the burden being carried by the space shuttle to a new, unmanned . . . launch vehicle that offers increased payload capacity and (can be made) wherever practicable from existing components to save time and costs.

“The resulting reduced demand for the shuttle will help relieve the schedule pressures which have contributed to some of the problems the program has encountered.”

Quayle, who heads the National Space Council, said the panel would meet again in six months to determine what progress NASA had made on the recommendations.