The glider-like manned space shuttle, whose cost was estimated five years ago at $250 million apiece, has climbed to as much as $600 million for each 74-ton spacecraft.

Only one of five shuttle craft has been built, at a cost of almost $500 million. A second is being assembled at Rockwell International's factory in Palmdale, Calif., and is expected to cost a little more than $500 million. The National Aeronautics and Space Administration told Congress three months ago the last three would cost $550 million apiece but a new estimate could push that cost to $600 million.

"We expect by the end of this month a new proposal from Rockwell for the last three spacecraft," said Christopher C. Kraft Jr., director of the Johnson Space Center in Houston, where the shuttle is managed. "I don't know how much Rockwell's going to suggest but they're for sure going to cost more than the last estimate we got."

Labor takes up at least 70 per cent of the shuttle's cost right now, with an estimated 48,000 workers earning more than $5.5 million a day assembling the second shuttle craft and getting the first one ready for manned flight tests.

NASA hopes to have congressional approval to start construction of the third shuttle craft before the end of the year. The third spacecraft in a line of five is earmarked for shipment in March, 1982, to Vandenberg Air Force Base in California where it will be used by the Pentagon to haul its satellites into earth orbit.

A fourth shuttle craft is due to be built by March, 1983, and a fifth by March, 1984. One of the last two will go to the Air Force, the other to NASA for its own use at Kennedy Space Center in Florida where a shuttle takeoff facility and landing runway are nearing completion.

Similar facilities are being built by the Air Force at Vandenberg AFB, where two shuttle craft will serve as workhorses for the Pentagon's satellite fleet over the next 15 years. The two Pentagon shuttle craft will be paid for by NASA.

NASA might have a fight on its hands in Congress over the last two shuttle craft. The General Accounting Office over the weekend suggested that Congress consider delaying the last two of the five-craft fleet, mostly because the shuttle is still an unproven space transport system.

Together with the Air Force, the space energy is wary of any congressional delay in approving the five-craft fleet. Its officials worry that a delay will mean shutdown of the dozens of subcontractor work forces around the country and the shuttle assembly line in California that will be extremely difficult and costly to start up again.

They also worry that labor and materials costs will escalate so rapidly in the next five years that Congress will balk at the higher prictags a delay might bring. One NASA official estimated privately that a two-year delay in congressional approval would mean that each shuttle craft affected by the delay would end up costing close to $1 billion.

One major reason for the expected rise in cost for the last three shuttle craft is the rising price of aluminium and titanium, the two key metals used in the shuttle. The space agency bought both metals for its first two spacecraft three years ago when prices were lower but has held off buying metal for the last three.

Each shuttle craft weighs about 153,000 pounds and is the size of a DC-9 jetliner. It will have a crew of four astronaunts and even carry as many as six passengers. It will also be able to haul 65,000 pounds of cargo into earth orbit and is expected to replace every rocket now used by the United States except for the small Scout used to launch the smallest satellites into orbit.

The first manned flight of the shuttle Enterprise attached to the back of a Boeing 747 jumbo jet is scheduled for no earlier than June 16. The first free flight is due for the middle of August and the first oribital flight from Cape Canaveral in March, 1979.