Astronauts lose day of viewing in Astro-1 snag

December 04, 1990|By Luther Young | Luther Young,Sun Staff Correspondent

GREENBELT -- The Astro-1 observatory -- finally launched Sunday after years of delays -- lost a day of precious observing time before astronauts grabbed the reins from a malfunctioning automatic pointing system and began manually directing the telescopes at celestial targets.

"It's like you would point a rifle from a moving automobile," said mission manager Jack Jones last night from Marshall Space Flight Center in Alabama. "We had hoped this would be a much simpler job than it is."

Original plans called for science observations with the four telescopes aboard Columbia to begin early yesterday. Instead, officials at the center spent yesterday trouble-shooting and grimly watching 10 percent of the scheduled targets slip away.

"There's a definite loss as we go [of observations] we will not recover," said mission scientist Theodore Gull of Goddard Space Flight Center, who added that an ambitious schedule of 250 objects had been targeted over the 10-day mission.

Officials of the National Aeronautics and Space Administration said it could be early today before the Instrument Pointing System -- a movable platform on which three ultraviolet telescopes are mounted in the open cargo bay -- would be operating so that astronomer Samuel T. Durrance of the Johns Hopkins University and the six other astronauts could efficiently accomplish observations.

The crew includes commander Vance Brand, pilot Guy Gardner and mission specialist Mike Lounge. There are four astronomers aboard: mission specialists Jeffrey Hoffman and Robert Parker and the payload specialists, Dr. Durrance and Ronald Parise of Burtonsville.

Similar problems with the Instrument Pointing System showed up when it was flown during the 1985 Spacelab 2 mission, which carried telescopes to look at the sun instead of the stars, galaxies, supernovae and planets targeted by Astro-1 in the ultraviolet and X-ray regions of the spectrum.

"The computer software is extremely complicated and couldn't be tested in Earth gravity," said Arthur Davidsen, lead scientist for the Hopkins Ultraviolet Telescope. The software's performance was checked only through computer simulations.

He expressed guarded optimism that the system would soon be operating as expected, even as his lingering euphoria over the launch was nibbled away. The Hopkins telescope has already missed its first opportunity to view the brightest quasar in the sky, he said.

Such high-priority targets will be rescheduled.

Dr. Davidsen pointed out there were "really no low priorities when you've spent a dozen years choosing targets. If we have to keep pointing manually, we would clearly get much less science than we had hoped for. It would be disastrous."

The four telescopes -- the Hopkins Ultraviolet Telescope, the Wisconsin Ultraviolet Photopolarimeter Experiment, the Ultraviolet Imaging Telescope and the Broad Band X-Ray Telescope -- appeared to be functioning well.

There was some good news for the Hopkins telescope team yesterday. Their instrument beat the other telescopes to "first light," obtaining a spectrographic reading of the ultraviolet "air glow" of Earth's atmosphere that will be needed as a background value when later observations are made in deep space.

And Dr. Durrance, 47, received a welcome message from home in the morning, from his wife, Becky, waiting at the Johnson Space Center in Houston with the couple's two children after the "wonderful, unbelievable, spectacular" launch Sunday.

"I told him he looked beautiful on TV," Mrs. Durrance said by phone. "And I was happy his dream had finally come true."

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