Hubble's Stellar Images A Year after the Repair Mission, the Space Telescope's Clear Pictures of Distant Galaxies Have Redeemed the Expensive Project in Scientists' Eyes

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With shades of yellow, orange, and blue -- and ever-dwindling shades of dollar-bill green -- astronomers are using the Hubble Space Telescope to paint breathtaking pictures of the universe.

In the year since the shuttle Endeavour and its crew salvaged Hubble, the $1.5 billion orbiting observatory has been giving humanity an unprecedented look at the heavens, peering ever deeper into the past and providing scientists who try to explain the cosmos with more questions than answers.

With new instruments scheduled to be added in 1997, the telescope is expected to push the limits of the observable universe out even farther.

"I'm trying to think of how to phrase this without sounding hyperbolic, but this has been the most spectacular year in my professional career," says David Leckrone, the Space Telescope's senior project scientist at the National Aeronautics and Space Administration's (NASA's) Goddard Space Flight Center in Greenbelt, Md.

"There certainly is much more excitement now than there was a year ago," agrees Boston University astronomer Ken Janes.

In December 1993, the world watched with fascination as shuttle astronauts danced a delicate minuet with the bus-sized observatory. Placed in orbit in April 1990, it was to be one of the cornerstones of NASA's "Great Observatories" series of astronomical satellites. It had been billed as the telescope that would gaze with exceptional clarity from above the atmosphere to the very edge of the known universe. It was to help answer the most basic questions: How old is the universe, and what is its future? What is it made of? How do galaxies, the universe's basic building blocks, evolve? Are there other planets around other stars? Can we observe black holes?

Hubble Telescope Finds Redemption in the Stars

Initial images of a star cluster that was 1,260 light years away seemed to be harbingers of discoveries to come: The image quality was said to be 10 times better than Earth-bound telescopes could deliver. But two months after the shuttle delivered Hubble to space, engineers trying to align the telescope discovered a significant flaw in its mirror that sent hopes plummeting. Subsequent investigations found fault with NASA's oversight and management. Meanwhile, ground-based telescopes were being planned to take advantage of new technologies to compensate for the blurring effects of Earth's atmosphere -- approaching, at least on paper, some of Hubble's capabilities for roughly a tenth of Hubble's cost.

By August 1990 hopes began to rise again as astronomers reported views of the core of Galaxy NGC 7457, again, with 10 times the quality of ground-based observations. The mirror's flaw had its greatest impact on Hubble's ability to resolve very faint objects, such as very distant, early galaxies.

Astronomers were further encouraged in 1992 as Hubble images allowed them to study candidates for black holes and to make observations that would allow them to refine distance measurements that in turn could be used to refine estimates of the age of the universe.

Meanwhile, NASA had begun planning the repair mission, which would replace the wide-field and planetary camera with one using newer technology and corrective lenses, as well as give three other critical instruments "glasses" to compensate for the mirror's flaw.

On that mission, "manned and unmanned spaceflight came together," Dr. Leckrone says. "The mission itself went splendidly. We began getting images four to five weeks earlier than expected." And the performance of the refurbished Hubble exceed even the original design specifications, he says.

The mission "blew me away," agrees Anne Kinney, an astronomer and director of educational programs with the Space Telescope Science Institute (STScI) in Baltimore. "I would have been delighted if it had been 75 percent successful, but it was 100 percent successful. …


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