Martin Marietta Corp., which has eight reservations for commercial satellite launches on its Titan rockets, announced yesterday that it has signed an agreement to use government launch facilities at the Cape Canaveral Air Force Station in Florida.

It is the first such agreement since the Air Force announced last week that it planned to rent military launch pads and other facilities to support commercial ventures.

"This allows us now to go and finish signing our contracts with commercial satellite builders and users," said a Martin Marietta official who asked not to be identified. "This was one piece of the process we had to complete. We had to be able to tell them we have a launch pad."

The official said he didn't know how much the use of the Air Force facilities will cost, but said Martin Marietta will reimburse the military for "whatever range support is necessary, for range safety, tracking and associated services."

The Air Force station adjoins the Kennedy Space Center. The commercial launches will begin in 1989.

Until now, either the National Aeronautics and Space Administration or the Air Force have launched all satellites, hiring personnel from the rocket manufacturers to help.

But the Challenger accident last year and a decision to remove commercial satellites from the space shuttles' launch schedule prompted establishment of a private launch industry. McDonnell Douglas Corp. and General Dynamics Corp. also are selling launch services to owners of satellites. "This is a major step in maintaining space leadership through cooperative efforts between the Defense Department and commercial industry," Air Force Secretary Edward C. Aldridge said.