Computer Loss Halts Columbia's Star-Gazing
Dec. 07, 1990
CAPE CANAVERAL, Fla. (AP) _ Space shuttle Columbia's star-gazing mission suffered yet another major setback when the astronauts Thursday lost their only working computer terminal for operating a $150 million observatory.
Observations, already lagging far behind, were halted as a frustrated NASA scrambled to devise a plan to control three of the telescopes from the ground.
''We've got to bootstrap ourselves from ground zero,'' said mission scientist Ted Gull.
Controllers developed a procedure in which the telescopes and their pointing system could be guided by commands from the ground. The astronauts, aided by data from the ground, could manually steer the telescopes toward desired targets with a joystick and television cameras.
Using that process, one telescope observed a supernova Thursday night, said mission manager Jack Jones. Scientists planned to attempt additional observations through the night with the other telescopes.
''We've now got a way to operate,'' Jones said.
But Jones could not say yet how well the new process would work or how many observations may be lost because of the latest problem.
It was the latest in a series of blows to the mission, which was delayed six months by shuttle fuel leaks and suffered instrument failure within a few hours of Columbia's liftoff Sunday. The shuttle is to land Tuesday.
''I'm not sure whether to smile ear to ear or cry,'' said William Blair of Johns Hopkins University, revealing data of a supernova remnant that the school's telescope made before being shut down.
The four astronomers aboard Columbia were forced to halt observations Thursday morning when a flight deck computer overheated and automatically turned off. Moments before, they had smelled a burning odor similar to one that filled the cabin Sunday when they lost the only other terminal for operating the observatory.
The astronauts had been managing the Astro observatory's three ultraviolet telescopes with the one remaining terminal.
When the first failed computer was disassembled Thursday, its air vents were found to be clogged with lint. The National Aeronautics and Space Administration tried to bring that terminal back on line, but the smell reappeared and astronaut Jeffrey Hoffman quickly turned the machine off.
''No joy on the test. Power is off,'' Hoffman said.
Mission Control's James Hartsfield said there was no large release of harmful fumes and the crew's air was fine. The astronauts had their breathing helmets ready just in case.
Before Thursday's computer failure, the astronauts have had to manually steer the telescopes because of nagging problems with the automatic pointing system, which was used sporadically.
As a result of the slower, less precise manual method, many stars were dropped from the observing schedule. Astro was supposed to have begun examining galaxies, quasars and other high-energy objects late Sunday.
Scientists scrapped more targets Thursday in light of the computer problem. Gull said he could not estimate how many of the planned 250 objects had been lost.
''I would be lying if I said I wasn't frustrated. I mean, I am frustrated,'' said Mary Jane Taylor, part of the University of Wisconsin telescope's team.
''But I don't think any of us thought that this was going to be error free,'' she said. ''I don't think anybody thought it was really going to go 100 percent smoothly.''
To salvage the rest of the mission, NASA planned to operate the telescopes via computer commands sent from the ground if neither flight deck terminal could be repaired. The astronauts, aided by the ground data, would use a joystick and TV monitors to steer the instruments in the open cargo bay toward desired stars.
Johnson Space Center in Houston would control the instrument pointing system in bringing the telescopes back up one by one, assisted by astronomers at Marshall Space Flight Center in Huntsville, Ala. Ground controllers practiced moving the observatory Thursday afternoon.
''Acquisition is going to be difficult,'' Gull said. ''It's certainly going to be a close teamwork effort.''
Such a procedure was never practiced before the mission, Gull said.
''We anticipated that an individual instrument might need (to be) controlled from the ground. But we didn't anticipate that we might have to control all three instruments from the ground,'' he said.
Astro's X-ray telescope was unaffected. The instrument is operated by computer commands sent from Goddard Space Flight Center in Greenbelt, Md., and has its own pointing system.
The X-ray telescope's observing schedule was being revamped, however, to take advantage of the ultraviolet instruments' idle time. Many of the targets were supposed to be viewed simultaneously by all four telescopes.
Ultraviolet light and X-rays are absorbed by the atmosphere and thus invisible from the ground. Astronomers had been counting on Astro's results 218 miles above Earth to improve their understanding of objects that emit such radiation.
While waiting for observations to resume, Columbia's seven-man crew photographed Earth and relaxed.
''We're just sitting here, you know, enjoying the view, doing a few other things,'' said astronaut Sam Durrance.
The astronauts still planned to conduct a live science lesson Friday for more than 40 middle-school students at two NASA centers. The youngsters will be able to question two crew members.