KENNEDY SPACE CENTER, Fla. — A critical launch pad test-firing of the space shuttle Discovery's main engines was delayed Friday for three more days, and it seemed almost certain that the first post-Challenger shuttle flight would slip into October.
The postponement of the firing from Monday until Thursday, the third delay in a week, came while the launch team was pumping propellant into Discovery's huge external fuel tank, the first time a shuttle had been fueled since Challenger exploded shortly after liftoff on Jan. 28, 1986.
Once the liquid hydrogen and liquid oxygen started to flow, pumps, lines and sensors not used in 2 1/2 years began to fail.
Faulty sensors and a balky oxygen pump were corrected, but a hydrogen line leak and a second bad oxygen pump could not be repaired quickly and launch director Bob Sieck called off the countdown.
All the problems were associated with launch pad ground support equipment and were not on the shuttle itself.
The 20-second firing of the three main engines is to test several modifications made since Challenger and is considered crucial to certifying Discovery for flight.
With the latest delay, NASA must face the real possibility that the launch will be postponed until October.
Official documents Thursday had listed Sept. 13 as a target date for launch. But that was before the latest postponement and did not allow for time to repair a major problem plaguing Discovery, a small gas leak in a vent line for a steering engine system separate from the main engines.
In Washington, meanwhile, a federal appeals court ordered NASA to release a tape recording made by the Challenger crew that ends with pilot Michael J. Smith's poignant "uh oh."
NASA officials said an appeal is likely.
NASA has refused to supply a copy of the tape to the New York Times, asserting that release would encroach upon the privacy of the astronauts' families.