NASA: Hubble's new glasses OK

Corrective lenses cleared of defects

NASA has cleared of defects the new $100 million camera that astronauts plan to install on the optically flawed Hubble Space Telescope this December, a space agency spokesman said Monday.

The orbiting observatory is to be repaired during an 11-day space shuttle mission to lift off Dec. 2. The mission will feature at least five spacewalks.

The 610-pound, wedge-shaped Wide Field/Planetary Camera II, or WFPC II, is one of two large components NASA plans to install on the telescope to correct the optical flaw discovered two months after the observatory was launched in April 1990.

Late last week, space agency officials grew concerned because they had not been able to explain the results of a month-old test at NASA's Goddard Space Flight Center in Greenbelt, Md.

The test showed a small but significant focusing problem with the new camera.

But during the weekend, engineers at Goddard were finally able to pinpoint the 8-millimeter focusing error in faulty test equipment used to check the camera before it was shipped to the Kennedy Space Center in Florida nearly a month ago.

"We were always pretty confident of that," Goddard spokesman Jim Elliott said Monday. "Between Friday and Sunday they were able to come up with the solution to the measurement problem."

Had the efforts by the test team been unsuccessful, the new camera would have been returned to Goddard for further testing. In a worst case scenario, the WFPC II would have been left behind or the flight delayed.

The WFPC II is actually two cameras, one that takes high resolution images of planets and relatively nearby galaxies and a second to take images of the faintest and most distant objects in the universe.

The second major component that astronauts plan to install on the space telescope to correct its optical flaw is the $50 million, 500-pound Corrective Optics Space Telescope Axial Replacement or COSTAR. Its optics and mechanical systems have not been questioned.

A flaw within the Hubble's 94-inch-wide primary mirror was discovered three years ago when an unexpected fuzzy border appeared on the images of the most distant objects the space telescope was aimed at.

The corrective elements within the WFPC II and the COSTAR were carefully designed to remove the distortion from the light stream before it reaches the observatory's cameras and spectrometers, much like eyeglasses correct blurry vision in humans.

In addition to those two large components, the shuttle's spacewalk team also plans to replace the space telescope's electrical power generating solar arrays, three of its six gyroscopes, a magnetometer, a computer processor and a backup power component on the spectrometer.