The delay was especially disheartening: Perfect weather had been forecast, and it had been a year since a technical problem forced a scrub during a countdown.
NASA said it would try again Friday afternoon to launch the shuttle, its crew of seven and its menagerie of more than 2,000 creatures-if the processor can be replaced by then. Managers planned to meet Thursday to decide whether that was feasible.
CBS News Space Consultant Bill Harwood reports that if Columbia is not off the ground by Friday, the flight will be delayed at least 96 hours more to replace research animals and top off internal fuel supplies.
Columbia's two so-called network signal processors are vital. They are supposed to send and format data between the shuttle and the ground, and the shuttle and communication satellites. During routine testing Thursday morning, one processor failed to receive data, said NASA spokesman George Diller. The other worked fine.
NASA officials told Harwood that the failure is an isolated event, and not a more widespread problem affecting the rest of the shuttle fleet. NASA engineers will swap Columbia's processor with a shoebox-size replacement unit borrowed from the shuttle Endeavor. They expect to complete the swap by 5 p.m. Thursday and restart the countdown.
Shuttle managers put off loading Columbia with fuel this morning as engineers first tried to fix the processor with computer software.
Columbia's astronauts learned of the problem when they awakened, and were three hours away from boarding when the launch was called off.
Columbia's animal passengers, however, already had been loaded and most were to be taken off Thursday.
NASA's oldest and heaviest shuttle already was stuffed with 2,052 creatures for its 25th journey into space. The crowd included pregnant mice, rats, snails, fish, and crickets.
Columbia's Neurolab mission promises to be the most in-depth study ever of the brain and nervous system in weightlessness. The 26 experiments are intended to shed light on aging and other health problems in orbit and on Earth, and perhaps make it easier for astronauts one day to camp on the moon or travel to Mars.
Like the elderly, astronauts in space suffer from vertigo, insomnia, imbalance, reduced blood pressure, and weakened bones, muscles and immunity.
To help solve some of these physiological puzzles, the four men on board will undergo extensive neurological testing during the 16- to 17-day flight.
The animals also will be probed and observed.
All four oyster toadfish, for instance, already have electrodes embedded in their heads to measure nerve impulses; 24 rats have heart-rate and temperature sensors implanted in their skulls. The 18 pregnant mice will be dissected in orbit, as wilsome of the 152 rats. The rodents are the most ever for a single space mission.
Columbia's other test subjects include 135 snails, 229 swordtail fish, and 1,514 crickets-the first crickets ever bound for space. There will be no chirping: None of the insects are old enough to have the wings they need to rub together for a serenade.
By Marcia Dunn ©1998 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed