The U.S. space program is clearly eclipsed by Moscow's only in one area, the operational use of crews in Earth orbit, and no nation has a space lead, a congressional study says.

The study, prepared for the Senate Commerce Committee and its Space Subcommittee by the Congressional Research Service, noted that the lead in that area existed long before the 1986 Challenger shuttle disaster and will remain long after the shuttle goes back into service."No single country is `ahead' of all the others in space," the CRS report said, and despite the edge in operational experience and "despite the headlines of the last few months, the Soviets have not suddenly taken the lead in space."

"If the United States chooses to compete with the Soviets in this area (operational experience), it must have the ability to leave crews in Earth orbit for very long periods of time, not the 7-10 days achievable with the shuttle in its current configuration," the report added.

The report said the Soviets are not ahead technologically, declaring, "Their crews are able to compensate for their limited technological sophistication . . . (and) they are only now beginning to have a space station with the technical capability of the 1973 U.S. Skylab."

Committee Chairman Ernest Hollings, D-S.C., noted that while Congress sorts out appropriations bills that could affect the nation's space program, "It is vital to understand what other countries are doing in space, especially the Soviet Union. It is vital that our country have the best technology and capability for performing research in space over long periods of time."

A central element of U.S. space plans is a space station, something that may cost $20 billion or more, and given differing amounts of money in the House and Senate appropriations bills covering the National Aeronautics and Space Administration. The shuttle program, however, is given enough money to keep it fully operational once flights resume in late summer.

The administration sought some $967 million for the space station, still only in the planning stages. Current schedules call for construction work to start in 1989 and for the station to be in orbit in the late 1990s. In addition to providing a work station in space, it could be used for a stepping stone to Mars. The Soviets have their Mir space station in orbit.

The House and Senate have allocated different amounts of money to the project, and the House seeks to leave the space station's fate in the hands of the next president. The differences will be resolved by a conference committee.

The Senate has effectively put up $800 million, although just $200 is specifically earmarked for the space station. The House provided $902 million, but said half the money cannot be spent until April and gave the next president the option of telling Congress to junk the project and reallocate the $451 million being held up.

The report, an update of one first produced in 1982 and covering 1981 to 1987, noted that space is not the exclusive province to the two superpowers. China, India, Japan and the 13-member European Space Agency all have demonstrated the ability to put satellites in space.

The United States, it said, leads in the technology of piloted space craft, the Soviets have more hours in space, both nations have the ability to make spacewalks, and Moscow is ahead in meeting announced goals.

The report said a direct comparison of the roughly 100 Soviet space launches a year to the 15 to 20 done by the United States is a bit misleading.

"This comparison shows how far the Soviets are behind, since the difference is primarily attributable to the low level of Soviet technology. They have to launch that many more satellites to accomplish the same objectives the United States can meet with fewer launches," the report said.

The 278-page document also noted the Soviet form of government makes long-range planning easier in comparison to the ebb and flow associated with U.S. budget cycles.