The idea that space is a place where such things as transistors and vaccines can be made better and cheaper than on Earth is sharply challenged in a report by the National Academy of Sciences.

The report, being released this week after a year's work by a committee of 12 well-known material scientists, concludes that manufacturing in space will be so much more expensive than on Earth that it may never become a useful commercial tool.

"The committee has not discovered any examples of economically justifiable processes for producing materials in space," the report said, "and recommends that this area of materials technology not be emphasized" by the National Aeronautics and Space Administration.

Declaring that most things proposed for space manufacture can be made just as easily as on Earth, the report throws cold water on the notion that NASA's returnable space shuttle will turn into a gravity-free factory producing new wonder drugs and unheard-of exotic metals.

"Man has been aware of gravity for a long time and has coped pretty well with it," said Dr. William P. Slichter, director of materials research at Bell Laboratories and chairman of the committee. "No reason exists to think there will be any breakthroughs in space."

While seeing little of commercial benefit in space manufacturing, the report nonetheless concluded that the processing of materials in the weightless state of space promises rich rewards in pure science. The report specified boiling, combustion and melting as three fields in which space offers unique opportunities for study.

"The onset of molecular turbulence, even the onset of the boiling of water is ill-understood," Slichter said. "Since gravity dominates these phenomena, experiments carefully planned and carried out in the near-zero gravity conditions of space would be highly revealing."

The absence of gravity would also mean the absence of buoyancy, the report said, and this could be turned to scientific advantage. Buoyancy would no longer be a force causing different fluids to mix unevenly and causing lighter materials to rise and heavier ones to sink.

"The phenomenon of flame would be an interesting subject of study in space," Slichter said. "Bouyancy on Earth has a great deal to do with the nature of flame on Earth, the way hot air rises and moves flames around and controls it."

Finally, the absence of gravity would be a boon to scientists studying materials that now have to be held inside a container. Ceramics and metals like tungsten and titanium that are worked at very high temperatures could be worked in containerless conditions.

"Things that melt at high temperatures usually attack what they're contained in and are usually contaminated as a result," Slichter said. "This wouldn't have to happen in space."

But nowhere did the academy find any such promise in the commercial side of space materials processing.

The scientists studied two areas of commercial space processing: the separation of biological materials like vaccines and the growth of silicon crystals for use in electronic devices.

They found no clear-cut advantage in either case over eathbound processes. They found the process used on Earth to produce and purify biologicals working well and still being improved. Crystals grown in space are purer than those grown on Earth but the scientists saw little advantage in the difference.

"The results are not sufficient," they said, "to permit concluding whether growth in space of crystals for commercial electronic devices is or is not viable."