HUNTSVILLE, ALA. -- National Aeronautics and Space Administration chief James Fletcher is scheduled next month to announce winners of major contracts for the $14.6 billion space station, according to agency officials.

Five companies -- including Martin Marietta Corp. of Bethesda -- are vying for four contracts to build sections of the space station planned to orbit about 250 miles above earth. Construction is to begin in 1994.

Boeing Co. of Seattle and Martin Marietta are competing for the contract to build the living and working stations for the space station, which is expected to function for 30 years.

Fairfield, Conn.-based General Electric Co. and its subsidiary RCA Corp. are bidding on a package to be managed by Goddard Space Flight Center in Greenbelt. Goddard will manage the attached payload and flight telerobotics system.

The Canoga Park, Calif.-based Rocketdyne division of Rockwell International Corp. is the remaining bidder for the power systems package managed by the Lewis Research Center in Cleveland.

The Johnson Space Center in Houston will manage the basic structure of the space station, the command center and handle the technical management of the manned systems and crew training. McDonnell Douglas Corp. of St. Louis and Rockwell are bidding on the Johnson work package.

"I think more than anything else it will be a stepping stone for manned exploration of space," Luther Powell, manager of the space station project for the Marshall Space Flight Center.

"We need to find out how long we can stay in space as a basis for manned exploration of the planets," said Powell.

According to the space agency's latest estimate, the space station will cost about $14.5 billion, Powell said. The independent National Research Council said that when the cost of supporting space shuttle flights, personnel and other operational costs are figured in, the bill to develop and deploy the eight-person space station will be at least $25 billion.

NASA spokesman Mark Hess said the choice of contract winners could be announced as early as Nov.