Congress' Office of Technology Assessment reported yesterday that a second-generation supersonic airliner could capture up to one-third of the world's long-range market, but that the United States is not spending enough to retain an option to build the plane.

The report, requested by the House Science and Technology aviation subcommittee, seems certain to warm up an old debate about whether the government should finance a high-technology aircraft no manufacturer is willing to try alone. After research is completed, the report said, it could cost $6 billion to $10 billion to get such a plane into production.

Rep. Tom Harkin (D-Iowa), chairman of the subcommittee that sought the report, said in an interview that he intends to propose a five-year, $100 million annual appropriation for advanced supersonic transport (SST) research because "I think it's something we really have to have to keep up on." U.S. research has been limited to about $10 million per year since 1971, when Congress killed further government participation in development of first supersonics.

That left the field to the Russian TU144 and to the British-French Concorde. The major problems that have plagued the Concorde -- noise and fuel inefficiency -- remains unsolved.

The report said, however, that there has been substantially progress in the development of a quieter and more efficient engine -- although it would not be as efficient as the engines on new-generation aircraft that fly at slightly less than the speed of sound.

Further, the report said, a second-generation SST would have substantially improved range and payload compared with the Concorde, which can carry only 100 slightly cramped passengers, although it takes them from New York and Washington to Paris and London in half the time normal airplanes do.

The second-generation SST could carry about 300 passengers, the report said, and would have the range for long-haul Pacific routes that the Concorde cannot manage without refueling.

That leaves the problem of the sonic boom, which sounds on the ground like an explosion. It is caused by the shock wave created when an airplane passes the speed of sound.

Because of the boom, it is illegal for civilian aircraft to fly supersonically over the United States. Thus New York to Los Angleles -- the most lucrative domestic market for speedier jet travel -- is closed to supersonics. "Research indicates there may be ways to lower sonic boom pressures," the report said, "but practical aerodynamic solutions appear to be many years off."

Research since 1971, according to the report, has yielded new wind designs that improve performance; new ways of handling titanium, a high-strength lightweight metal that is difficult to work with, and new engine concepts that promise better efficiency. Accelerated research efforts are needed, however, to reach the point the United States could make a decision, the report said.

The most efficient projected advanced supersonic would consume about 5,850 British Thermal Units (BTUs) of energy per passenger mile (compared to 10,000 for the Concorde), the report said. The most efficient subsonic would use 2,550.

The report argues that because of greater productivity it would take only about 400 advanced supersonic transports to fill the transportation requirements met by 850 subsonic jets. Therefore, if supersonics were not introduced, "worldwide commercial aviation fuel consumption would still be . . . only 5 to 10 percent less." The report estimates that 400 planes would bring $50 billion in current dollars and would represent one-third of the long-range transport market.

U.S. and European manufacturers said in interviews that they do not expect any country or company to attempt advanced supersonic development alone. Consortium building is regarded as a must because of the enormous capital requirements, they said.

What of the Concorde? Developed for $3 billion, it will never recover its capital costs and five of the 16 Concordes built are still unsold.

However, Concorde is in one sense a hit. British Airways is selling more than 90 percent of its seats between New York and London and 70 percent between Washington and London. Air France claims 73 percent between New York and Paris and 53 percent between Washington and Paris. The industry break-even point for subsonic flights is about two-thirds capacity.