Problems reported with shuttle's observatory

December 03, 1990|By Frank D. Roylance | Frank D. Roylance,Evening Sun Staff

GREENBELT -- Problems with a telescope pointing system have delayed by at least 12 hours the start of astronomical observations by the Hopkins Ultraviolet Telescope and three others aboard the space shuttle, Columbia scientists said today.

"We have lost about 15 to 20 pointings at this time, which we will not recover," said mission scientist Ted Gull, of the Goddard Space Flight Center. About 230 pointings were planned during the 10-day mission.

The shuttle is scheduled to return to Earth on Dec. 11 at 9 a.m.

Hopkins scientists today did manage to take their first scientific reading with the Hopkins Ultraviolet Telescope -- the first by any of the four astro telescopes.

Spokeswoman Lisa Hooker said the scientists at 11:30 a.m. took a spectrographic reading of the fringes of Earth's atmosphere above the shuttle. The chemical data it revealed must be figured into any data received later from stars and galaxies.

"Getting started is taking a lot longer than we anticipated," Gull said, adding that "I don't think I've ever seen a telescope come in on schedule."

Mission manager Jack Jones said new computer commands had improved the performance of star trackers in the pointing system. But more refinements were to be transmitted to the spacecraft late today.

"It's a very complex system, and we had to get it . . . deployed and free of gravity before we could get everything back into alignment," Jones said. "This is an expected phenomenon we would have to work with any star tracker."

The pointing system is similar to one that gave scientists trouble on a 1985 shuttle mission. If it can't be made to work properly, Jones said, controllers can switch to another, less precise pointing system on board.

Technicians were also working to correct alignment problems on the Broad Band X-ray Telescope, which is mounted on a swivel separate from the ultraviolet telescopes.

But the Hopkins Ultraviolet Telescope itself and the three others that make up the $148 million Astro Observatory were all reported to be "up and ready to go" once the pointing problems are fixed.

Problems with a balky computer inside the Wisconsin Ultraviolet Photo Polarimeter Experiment were fixed earlier today, Jones said.

The Hopkins telescope and two other ultraviolet instruments in the shuttle's payload bay all depend on the same Instrument Pointing Systems that technicians were trying to fix.

Hopkins scientists said the system must guide their telescope to the bright star Capella, 40 light-years from Earth in the constellation Auriga, so that they can finish focusing the instrument, the last step before beginning scientific observations.

"HUT is still working fine. We're just waiting on the IPS [instrument pointing system]," said Hooker.

The Astro Observatory is designed to explore some of the hottest and most violent regions of space, which generate radiation in the X-ray and ultraviolet wavelengths.

Among the first targets the telescopes will seek are the brightest quasar in the sky, called 3C273, Supernova 1987A and the Crab Nebula, which is the brightest source of x-rays in the sky.

Baltimore astronaut Samuel T. Durrance was said to be "cool as a cucumber" on board Columbia today as he worked to get the Hopkins telescope ready to explore the stars from the orbiter's cargo bay.

The Astro observatory was rocketed into orbit early yesterday after more than 12 years of planning and 4 1/2 years of flight delays.

The near-perfect launch, monitored from the Goddard Space Flight Center here, was followed by yesterday's telescope test.

Last night, the Columbia crew and mission controllers successfully opened the Hopkins telescope's delicate spectrograph to the harsh vacuum of space. But because of the pointing problems, HUT was unable to find Capella.

Still, using one of the ultraviolet telescopes during a test last night, the crew focused on the "first light" -- a star called Beta Doradus that was selected for testing purposes, not scientific observation.

"Everyone is gathering around the Christmas tree," said Stu Clifton, an assistant mission manager at the Marshall Space Flight Center in Huntsville, Ala., where most of the data from the shuttle are being gathered.

The long-delayed mission was launched at 1:49 a.m. yesterday in a spectacular nighttime liftoff that brought tears to Arthur Davidsen's eyes.

"My knees were shaking and my heart was pounding," said Davidsen, the principal investigator on the HUT project for the past 12 years. He watched the launch at Cape Canaveral, Fla., before flying to Huntsville.

Samuel T. Durrance, a Hopkins research scientist who lives with his wife and two young children in Lutherville, is one of two Marylanders aboard Columbia helping operate the four Astro telescopes during the 10-day mission.

Durrance is assigned to operate HUT during the 12-hour day shift.

His wife, Becky, was in Florida yesterday to watch the launch.

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