After a summer of Hubble Trouble and leaky shuttles, the fact that a deficit-burdened Congress last week handed NASA a 13.5 percent budget increase, including $1.9 billion for its controversial space station Freedom, should be welcome news for space enthusiasts.

At the same time, Congress has caused a tizzy by putting new, unusually specific budget and technical limits on design of the space station, the National Aeronautics and Space Administration's most costly and controversial project. The restrictions push the project away from one of its major purposes -- medical research centering on human space exploration -- and toward another -- microgravity research aimed at studies of materials and fluids in weightlessness.

As with most things related to the space station, reactions are mixed. They range from dismay at the notion of congressional committees taking over the role of engineers to relief that the station may advance from the drawing board to construction, whatever its form. Some critics of the space station are gleeful, others are alarmed.

"I don't think it's good public policy to have the Congress do the engineering on the space station," said space policy analyst John Logsdon of George Washington University, who has been critical of the station design and management. "But it seems to be necessary."

"This is a watershed, separating the thinking of the 1970s from the thinking of the 1990s," said Bruce Murray of the California Institute of Technology, former director of NASA's Jet Propulsion Laboratory and vice president of the Planetary Society and another leading station critic. "The bad news is it's being done by Congress and not the White House. The good news is the changes . . . are reasonable."

However, one independent analyst who has criticized the station said the key congressional language, which reportedly appeared suddenly late in the budget process, "is structured so that there are few options available to NASA."

"This is micromanaged so much it's ridiculous," said a NASA engineer in Houston. "You don't have any latitude. How are you going to keep good managers if they can never manage?"

A key congressional aide said he disagrees that Congress is micromanaging the project. "The big change is we made it plain we're going to start with microgravity {research} first."

NASA's blueprint called for steep funding increases beginning in 1991 for construction of the orbital laboratory. But lawmakers lowered budget ceilings for the project's peak years and directed the agency to separate the facility into smaller modules that can be launched sequentially in three self-contained, pay-as-you-go "phases." The plan also must require a "more realistic shuttle launch rate" than the current design. And, Congress warned, "new funding threats" could delay or kill the latter phases.

The appropriations language calls for launch of a "fully equipped U.S. microgravity laboratory . . . before the launch of any habitat." This should be "followed by a life science function," which must be separated from the microgravity lab.

The NASA budget, set at $13.9 billion for 1991, will be held at most to yearly increases of 10 percent through the mid-1990s, Richard Malow, staff director of the House Appropriations subcommittee that oversees independent agencies, told a meeting of Women in Aerospace. The station's funding will peak at around $2.6 billion instead of the $3 billion NASA had hoped for in 1993.

Although the House panel has long favored the microgravity lab, a NASA official said, "We never agreed that microgravity had a higher priority than life sciences and we never talked about doing them sequentially . . . . NASA may not be able to meet all of these requirements" under the new budget.

The microgravity lab is to be a largely automated satellite tended periodically by shuttle astronauts. The work could lead to new commercial products, such as pharmaceuticals, supporters say. Experts increasingly question the value of such research, but the Japanese and European partners in the space station are committed to it.

"Microgravity {research} is the centerpiece" of the international lab modules, the congressional aide said. He conceded that there may be "no golden nugget" payoff from the research but added, "since we're putting up the infrastructure, we ought to get first crack at it."

The second phase, for life sciences research, could be followed eventually by the permanently manned space outpost that was NASA's original aim. But Congress eliminated money for a crew rescue vehicle.

The restrictions may conflict with White House plans to use the space station to do the medical research for human missions to the moon and Mars, some officials said. The congressional language calls such missions "inevitable," but allows only minimal ground-based research on the Bush initiative.

Officials of NASA and the National Space Council, which advises the president, said they are reviewing the directives and may try to renegotiate them. NASA managers already had acknowledged the need for changes in the station design and had teams working to simplify it.

However, one NASA official said, it might be to their advantage to accept the lower budget levels, rather than fighting them, if in exchange they can get the predictability in funding that they want.

The congressional action also may affect the recommendations, expected next month, from the administration's Advisory Committee on the Future of the U.S. Space Program. "The jury is out on whether the committee will say anything regarding space station design," one source said. "That has been radically affected by what Congress has done in recent weeks and may have been superseded."

But the congressional aide said there is still latitude for the Future panel to make recommendations on the space station.

"You can make a compelling case" for building it incrementally, with microgravity research followed by life sciences research, he said. "Or you could make an equally good case for cutting out microgravity and putting it on a free flyer {satellite} and then directing a manned effort at the moon. Then you'd have the life sciences research done at a moon base."