But It’s Not Expected to Shorten Flight : Shuttle Has Faulty Fuel Cell Problem

The shuttle Discovery raced around the globe at speeds exceeding 17,000 m.p.h. Tuesday as ground controllers watched and listened through the most comprehensive communications system ever available to a manned space flight.

Unfortunately, nobody had much to say.

“We have a fairly low-key day,” is the way flight director Al Pennington put it.

The shuttle and its crew of five zipped around the planet, 187 miles up, in a “selective power down” mode, which meant that nonessential electrical equipment had been shut off because of a faulty fuel cell in a system that generates part of the power used aboard the spacecraft. The problem was not considered a hazard for the crew, and officials with the National Aeronautics and Space Administration said they doubted they would have to land earlier than planned--at 6:34 a.m. Saturday at Edwards Air Force Base.

Early Landing Unlikely

At worst, Pennington said, the flight could be cut short by one day and end on Friday, “but right now, we’re still planning on landing on Saturday.”

The problem was an erratic pressure reading on one of three tanks that supply liquid hydrogen. The liquid hydrogen combines with oxygen in fuel cells to produce electricity on board, with water as a byproduct. Turning off one of the cells while engineers on the ground studied the power system also meant turning off a few lights and other nonessential equipment.

While the crew carried out assigned chores quietly Tuesday, the shuttle was in contact with Mission Control 85% of the time--far more than any other spacecraft has been able to maintain--thanks to the communications satellite launched from Discovery during its flight in September. That mission was the first since the shuttle Challenger exploded on liftoff in January, 1986.

The Tracking and Data Relay Satellite lifted into orbit in September is now in full operation in a stationary orbit 22,300 miles above the Atlantic Ocean, over the northern coast of Brazil. With a sister satellite stationed over the Pacific, the network covers 85% of the globe. Except for a narrow “exclusion zone” over the Indian Ocean, a shuttle now can maintain almost constant contact with Mission Control. Although the two-satellite system was partially working for a Defense Department mission late last year, this is the first manned space flight since it has been fully operational, NASA officials said.

The system will be augmented by a third satellite, the one the Discovery deployed six hours after the shuttle’s launching from Kennedy Space Center on Monday. The newest satellite, a replacement, has reached its position above Brazil, and the older satellite there will serve as a spare.

Several Weeks to Check Satellite

Although it will take several weeks to check out the new satellite fully, officials said there had been no problem with it so far.

The two-satellite system can handle six times as much data as a string of ground stations that NASA will now be able to close. Each satellite can transmit 37 million characters--approximately the equivalent of 10 sets of encyclopedias--every second.

That capability allows NASA to transmit enormous amounts of data between the shuttle and ground controllers. The same satellites also transmit television pictures and audio communications, and they can serve as many as 24 spacecraft simultaneously.

With the satellite deployment behind them Tuesday, the Discovery crew members already could count this mission a success. They seemed content just to watch over a few experiments, mostly in silence.

Eggs Come Through Without a Crack

Pennington, the flight director, said the crew checked out 32 fertilized chicken eggs carried aboard the craft as part of a student experiment, and found no problems. The eggs, which will be hatched later for a study of how weightlessness affects developing embryos, appeared to have come through the rigors of liftoff without a crack, he said.

He offered little information, however, about the four rats that are part of another experiment.

“We don’t interface” with the rats, he said.

Before the launching, tiny holes were drilled into the rats’ hind legs so that their healing processes could be studied in space. The rats also are part of a student experiment.

The Discovery commander is Michael L. Coats, 43. Others in the crew are John E. Blaha, 46, the pilot, and mission specialists James F. Buchli, 43, Robert C. Springer, 46, and James P. Bagian, 37.