Shuttle astronomers busy storing stars' secrets

December 05, 1990|By Frank D. Roylance | Frank D. Roylance,Evening Sun Staff

Astronomers on board the space shuttle Columbia were busy today gathering valuable scientific data from their $148 million Astro Observatory, breaking into full stride after two days of hobbling technical failures.

The observatory's troublesome Instrument Pointing System (IPS) was functioning well enough early today to enable night-shift astronomers to do 35 percent of their planned observations, up from 17 percent yesterday. Today's day shift was said to be doing still better.

Mission scientist Ted Gull said the pointing system's performance should continue to improve as engineers require fewer IPS tests. "I'm hopeful we can keep on going, up close to 100 percent," he said.

The astronauts were still resorting to manual pointing for some targets because it was proving faster.

Scientists from Johns Hopkins University, meanwhile, were said to be "all smiles" today following overnight observations by the Hopkins Ultraviolet Telescope, being operated in part by astronaut Samuel T. Durrance, a Hopkins research scientist.

HUT team leader Arthur F. Davidsen said, "It's going great now, but we're not quite there yet. In our last 12-hour shift we got maybe a third of what we could possibly hope for."

Davidsen said he will be satisfied if he accomplishes two-thirds to three-quarters of what was planned for the mission.

HUT's biggest success overnight was an observation of the nearby white dwarf star G191B2B, an extremely hot star that has exhausted its nuclear fuel and collapsed to the size of Earth. Scientists expect the data to teach them more about the death throes of stars like our own sun. They also will use its light to reveal the abundance and temperature of primordial helium in the thin interstellar gas in our region of the galaxy.

"This is a first," said Davidsen. Helium is very difficult to observe and requires a telescope with HUT's unique sensitivity to extreme ultraviolet light.

HUT also obtained the first spectrum ever in the far ultraviolet of a globular star cluster.

Today, Davidsen hopes observations of the brightest quasar in the sky, 3C273, will shed light on a theory that quasars are powered by titanic black holes that are sucking up stars at the center of giant galaxies.

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