Washington — In the beginning was Project Mercury. Then came Apollo and the landing on the moon. The Space Shuttle followed soon after, and now (drumroll please, waving of flags and release of balloons) comes the US Space Station, a combination Holiday Inn, service station, and factory in orbit around Earth.
The space station, endorsed by President Reagan in his State of the Union address, is the next logical step in the US exploration of the universe.
Yet the National Aeronautics and Space Administration (NASA) has had a tough time getting the project approved. The Reagan administration, at first, was not enthusiastic. Many scientists still oppose a big-bucks space station effort, because they fear it will siphon money away from worthy but less spectacular space missions.
With a political campaign approaching, however, the space station - potentially a powerful symbol of US ''Right Stuff'' - has finally come into its own.
''The American people have always supported their space program,'' said NASA administrator James Beggs at a Thursday briefing for reporters. ''Space exploration is something that is truly in the American spirit.''
Mr. Beggs projects the space station will cost about $8 billion by the time it is permanently parked in orbit, around 1992. The President's 1985 budget will earmark about $150 million for the initial stages of the project.
Plans are only preliminary. One concept shows a space station that looks like seven water heaters soldered together, with a pair of solar panel oars stuck on either end. Another shows a giant, triangular web of steel.
Whatever its appearance, the station will be modular, providing living space, docking areas, and facilities for both manned and unmanned experiments.
NASA officials stress the possible commercial uses of a space station. Outer space, they say, could be a great place to manufacture certain drugs and grow ultrapure crystals for use in semiconductors.
The station will also likely be a space-borne garage for satellites in need of repair, a factory for constructing space structures larger than the shuttle can carry, and a staging point for journeys into deeper space - a manned expedition to Mars, for example.
''It's a bridge to the future,'' says John Hodge, director of NASA's space station task force. ''It is the next logical step in a series of space ventures.''
Experts outside government agree, if for no other reason than the fact that the Soviets already have an extensive space-station program. And a space station would give the space shuttle a more concrete mission; without it, they say, the shuttle is essentially a billion-dollar sports car with nowhere to go.
But many scientists complain that NASA, with its $8 billion program, is trying to go too far, too fast.
''For most legitimate missions of a space station, people get in the way,'' says John Pike, staff assistant for space policy at the Federation of American Scientists.
Mr. Pike would prefer a semi-inhabited space station, with a space shuttle visiting it every six months or so. He worries that the cost of keeping a permanent human presence in space will drain funds from other less spectacular projects, such as remote sensing satellites and the coming Galileo unmanned planetary probe.
''But there's this perception that the public will pay for these things only if they see people going along,'' ruefully says Dr. Von Eshleman, associate dean at Stanford University.
The White House has taken some time to give the project a green light. Science adviser George Keyworth was not convinced a full-blown manned space platform was the way to go; the Office of Management and Budget, as always, was worried about cost. (Some claim the station could eventually chomp up $20 billion or more.)
The aviation press was reporting as early as last fall that the project's approval was imminent. But the decision kept getting put back and put back, with the ''go'' signal finally being given relatively late in the budget decision process.
Part of the hemming and hawing may be attributable to the fact that the Defense Department has not been wild about the project. Military planners have said they fear the space station will siphon funds away from their own ''Star Wars'' budgets.