Utahn James Fletcher - who twice headed the National Aeronautics and Space Administration - says the flawed manufacture of the Hubble Space Telescope was one of NASA's largest foul-ups ever.
But scientists using innovation and computer wizardry have compensated for most of the flaws, have the telescope "working fairly well now," and plan repairs by astronauts in 1993 that should make it operate as well as originally hoped.Fletcher made the remarks over the weekend to the Brigham Young University Management Society - a group of BYU alumni and friends in Washington - as it toured the Goddard Space Flight Center in Greenbelt, Md. The center which oversees operation of the telescope.
The major problem with the telescope is that its main concave mirror was not ground as precisely as needed. Portions of the mirror nearest its center were all right, but the farther from the center the more incorrect the mirror grinding was. That produces fuzzy objects and a halo effect.
"It's not bad, it's just not as great as it should be," said John Klineberg, Goddard center director, who addressed the group with Fletcher.
Fletcher - a former University of Utah president who is now a distinguished professor at the University of Pittsburgh - admitted problems that led to the telescope flaw may have come during the end of his first tour as NASA administrator.
"We divided responsibility for that darn program between two centers, which was a terrible mistake. It was one of the worst-managed programs that NASA had ever done because of that and other things," Fletcher said.
"It wasn't a terrible screw-up, but it was the largest screw-up I think that NASA ever had. But fortunately, it works fairly well now."
Scientists have learned to take the digital information provided by the telescope and "sharpen" its focus by using computers to discard poor information coming from incorrectly ground parts of the mirror.
Klineberg said, "We have developed means by which we can deconvolute certain images and actually make it look like that image is much more precise. You can't do that when you're looking at a crowded field (of stars). But if you are looking at something isolated like Saturn, you can actually do that precisely."
With that, the Hubble is providing study of a previously undiscovered storm on Saturn similar to the great red spot on Jupiter. It has also discovered binary stars existing where Earth-based telescopes had seen only single stars.
"We have learned to live with it," Klineberg said of the flawed telescope.
But the flaws in the telescope still leave it unable to carry out its primary mission: determining the rate the universe is expanding by observing distant objects. But Klineberg said repairs scheduled for 1993 by space shuttle astronauts should fix that, too.
Among those repairs is replacing a wide-field planetary camera with optics that will correct for flaws in the mirror, which have been measured precisely through the months.
Also in planning is possibly installing a telephone-booth-size packet of other corrective optics for other scientific instruments aboard the telescope, replacing a failed gyro and possibly replacing solar-power panels.
"It should bring it back to original condition," Klineberg said.