Hubble, despite flaws, supplies useful pictures

October 05, 1990|By Luther Young

NASA unveiled a smorgasbord of color photographs from the Hubble Space Telescope yesterday, polishing the image of the $1.5 billion orbiting observatory despite its serious mirror flaw and continuing stability problems caused by a jitter from its solar panels.

The photos -- including the closest view ever of Pluto and its moon, Charon, plus some of the first visual evidence that black holes may exist -- have been taken recently as NASA engineers and scientists get the feel of Hubble and learn to make the most of its reduced capabilities.

"I'm cheerfully depressed," said Riccardo Giacconi, director of the Space Telescope Science Institute, located on the campus of the Johns Hopkins University. He spoke of the "glory and excitement of finally doing first-class science with Hubble."

The depression comes from knowing that "for three years, we won't be able to do what we wanted to do," Dr. Giacconi said at a media workshop on Hubble science results at the institute.

The National Aeronautics and Space Administration has scheduled a shuttle launch in June 1993 to replace the observatory's main camera with a new instrument fitted with a prescription lens to correct for the focusing flaw in the 8-foot main mirror. And space agency officials revealed yesterday that the repair mission may also replace the two 40-foot solar panels, which have been temporarily "shuddering" whenever they pass between day and night.

"We're leaning toward a replacement" of the extremely thin, electricity-generating arrays of solar cells, said Douglas Broome, Hubble program manager at NASA headquarters.

The panels, built for the European Space Agency, apparently twist slightly under intense heating and cooling in space and impart a vibration to the telescope that interferes with precise pointing at stars.

NASA is hoping to compensate for the problem with a computer software fix now scheduled to be beamed up to Hubble as early as Oct. 15. Originally set for installation in late August, it has been sidetracked by frenetic activity to "characterize" the mirror flaw.

The better the flaw on the huge reflecting mirror can be determined, the better the prescription for the new camera, known as the wide-field/planetary camera, said Christopher Burrows, institute telescope scientist.

In the meantime, upbeat Hubble engineers and scientists are continuing to check out or "verify" the observatory's five instruments, a process that should be complete by Nov. 15.

And they are proving that the two cameras aboard -- WF/PC and the Faint Object Camera, also provided by ESA -- are capable of discovery, if not the discovery originally promised and still expected after 1993.

Among the new releases was an unprecedented image of the outermost planet, Pluto, and its moon, and a stunning view of Saturn and its rings, although with less detail than provided by the close-up photos from the Voyager spacecraft.

But scientists point out that Voyager only briefly glimpsed Saturn, while Hubble can track from day to day such atmospheric features as a mysterious "white spot" now traversing the surface, the brightest and biggest spot to appear since 1933, said astronomer William Baum.

The institute's Holland Ford reported on detailed observations with the WF/PC into the bright core of an active galaxy 30 million light years away, where glowing, gaseous clouds apparently define a "cone" of influence with a likely black hole at its vortex.

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