Computer Failure Cripples Aim of 3 Astro Telescopes : Space: Lint blocking cooling ducts is blamed. The mission seems certain to miss most of its objectives.
The long-awaited Astro space mission suffered a devastating loss Thursday when an overheated computer failed, apparently because of excess lint, crippling the ability of crewmen to aim three of the four telescopes aboard the space shuttle Columbia.
The National Aeronautics and Space Administration is trying to salvage the mission, but it appears certain that the historic project, designed to examine some of the most violent objects in the universe, will miss most of its opportunities.
Some observations will still be possible, but control of the telescopes has been shifted to the ground. Crewmen will have to maintain a “joy stick” instead of a keyboard, and they will have to be coached on each move, which is a little like driving a hook-and-ladder truck from the rear seat.
It is a tedious process, and many hours that would otherwise have been used to observe the universe will instead be eaten up just pointing the telescopes. So, although Astro still has a chance of making major discoveries, a lot of time has been lost.
The bad news stunned scientists who have spent the last decade devoted to the project, because it came just after the troubled mission had returned some important scientific results that had scientists beaming.
“I’m not sure whether to smile ear to ear or to cry,” astronomer William Blair said. Most appeared closer to tears, and some are infuriated over a mission that has left them feeling betrayed by NASA.
Astro was to have flown many times, but NASA decided recently to limit the $150-million observatory to one flight, and now it appears that even that single mission will fall far short of hopes.
Arthur F. Davidsen of Johns Hopkins University, a scientist known worldwide for his pioneering research in ultraviolet astronomy and the chief scientist on his university’s telescope, said the best way to describe his mood is “angry,” particularly because the observatory will fly only once.
“A lot of people have invested their whole careers in this,” he said. Davidsen was just beginning to get spectacular results when the computer failed.
Columbia is equipped with two computers that are supposed to allow crewmen to command three of the telescopes. One of the computers failed the first day of the mission when it overheated. That forced the crew to share one command station, and more problems were to come.
The second computer also overheated and failed about 4:15 a.m. PST Thursday, and the astronauts were left with no means of fully controlling the instruments.
Flight Director Al Pennington speculated that the failures may have been caused by lint that accumulated in the cooling ducts beneath the computers, restricting the flow of air. In the absence of gravity, every speck of dust or lint floats around the shuttle, so there is always an abundant supply of material that can be sucked into air ducts. But Pennington indicated this was an unusually large amount.
“We’ve never seen that much lint,” Pennington said. The computers, supplied by the European Space Agency, are known to be sensitive to overheating, he said.
Crewmen used the “orbital vacuum cleaner” to clear out the lint, Pennington said, and the first computer was restarted. But when the crew smelled a burning odor, it was shut down.
Mission controllers here at the Marshall Space Flight Center and at the Johnson Space Center in Houston worked out a means of pointing the telescopes from the ground with a minimum of interaction by the crew after the first computer failed. That was partially successful late Thursday, but at best it will recover only a small fraction of the precious viewing time.
A fourth telescope, which studies X-ray emissions from space, is controlled from the ground by engineers at the Goddard Space Flight Center in Greenbelt, Md., and it is not expected to be affected, although there have been other problems in controlling that instrument.
The computer failure was the latest and most crippling problem to hit the troubled mission. Scientists had lost many precious hours of time because the telescopes tended to drift off target.
By Thursday morning, scientists had hoped to gather data from 187 targets. But NASA officials said they succeeded in only 70 cases, and in many of those successes the telescopes locked on target for only a small fraction of the desired time.
When they did succeed, however, they collected data that could not be collected before. The telescopes aboard Columbia study ultraviolet light and X-rays that are emitted by hot, violent objects in space. The Earth’s atmosphere absorbs light of that wavelength, so the observations cannot be made from the ground.
As light travels through space, it is imprinted with the signature of the material through which it passes, and the Astro telescopes have revealed details about the nature of the gas and dust through which the light passes. The telescopes also have given scientists information about the dynamic process that created the light--such things as matter being swallowed by a black hole, or “blobs” larger than the Earth being ejected from distant stars.
“We had a fantastic night,” astronomer Mary Jane Taylor of the University of Wisconsin said, referring to data that the Wisconsin Ultraviolet Photo-Polarimeter Experiment, WUPPE, collected before the computer failure.
Taylor’s results could help scientists understand the evolution of stars, and particularly why one hot, supergiant star called P Cygni is blasting off huge “blobs” of material.
“This has never been done before,” Taylor said.
It will be some time before she has analyzed her results enough to draw conclusions, and she hopes to get at least a little more data before the mission ends.
Thursday was also a bittersweet day for Davidsen. He collected data that may help answer questions about quasars, objects the size of our solar system that shine as brightly as a billion stars.
Scientists wonder if quasars are powered by giant black holes, objects so dense that their gravity pulls in everything within reach, including light.
When he finishes analyzing his data, Davidsen may be able to answer that. Normally, that would make him very happy. But he is an angry man because NASA has turned away from plans to fly Astro repeatedly.
Davidsen said scores of young scientists joined the program in expectation of doing serious science, and the decision against flying Astro again, coupled with the disappointments of this mission, means many will have little to show for their efforts.
“They pulled the rug out from under us,” Davidsen said of NASA.
NASA only recently decided against future flights, blaming the decision on a reduced number of shuttle missions in the post-Challenger era.
Davidsen said he understands that the decision has been made, even though he has never been officially notified. However, NASA chief scientist Lennard Fisk left no doubt about that during a press conference before the launch.
“This will be Astro’s only chance for glory,” he said.
