The space shuttle is not expected to make its maiden flight before July 1980, a new delay of seven months that may force at least four U.S. satellites to seek more expensive ways of reaching orbit.

"This slip means our first operational flight, which had been planned for February of 1981, will be delayed until September of 1981," National Aeronautics and Space Administrator Robert A. Frosch told a subcommittee of the House Science and Technology Committee yesterday. "This means some of our early users will have to shift to use the backup expendable launch vehicles to get their satellites into orbit."

Even as Frosch was speaking to the House subcommittee, the space agency contacted the Satellite Business Systems Corp., RCA, Comsat and the National Oceanic and Atmospheric Administration to inform them of the new delays in the shuttle test and operational flight schedules.

These four have reserved space for their satellites on either the first or second operational shuttle flight in 1981. Satellite Business Systems and RCA had reserved space for domestic communications satellites, Comsat for a worldwide Intelsat satellite and NOAA for its Geosynchronous Operational Environment Satellite.

Without the assurance of an early 1981 shuttle flight, the users might have to turn to more costly Delta and Atlas Centaur rockets to carry their cargo. Shuttle space would have cost the first four users between $8 million and $12 million. A Delta flight will cost $22 million and an Atlas Centaur even more.

Frosch said the latest postponement of the Nov. 9 target date was triggered mostly by delays in engine testing and in the producting and installation of the unique glass tiles that cover the space shuttle and protect it from the heat of re-entry.

At least 10,000 of the 33,000 tiles that must be bonded to the shuttle's metal frame have not yet been put on. Frosch said it may be Thanksgiving or even Christmas before these tiles are attached to the skin of Columbia, the first shuttle scheduled to fly.

"I feel we have one chance in five of launching by the end of the first quarter of 1980," Frosch said. "If I include some conservatism, I would have to add 10 to 12 weeks to that date. I believe the chance of flight by the end of the second quarter of 1980 is 50-50."

Privately, space agency officials are saying they see little chance of a flight before July 1. What they are aiming for now is a first flight in June or July 1980.

Frosch said the delays will cost $475 million, much of it to pay people who must be kept on the job longer than expected. Of the total, $70 million will be diverted from production funds, $185 million will come from a supplemental requested for the fiscal 1979 budget and $220 million from an add-on to the fiscal 1980 budget.

"This is the first time in a dozen years we've asked for a supplemental," Associate Administrator John Yardley told the House subcommittee, "and about the time ink dried on the first supplemental request, a whole bunch of other things started coming in" that forced NASA to make the second request.