Hubble rebounding from computer glitch

The Hubble Space Telescope is rebounding from its first technical scare since astronauts last month completed a successful final repair mission and released the observatory from space shuttle Atlantis.

Early Monday, a computer installed by the Atlantis crew had a hiccup.

The Science Instrument Control and Data Handling unit, or SIC&DH, which routes commands to Hubble's science instruments and relays their data, stopped sending a "keep alive" signal to Hubble's main computer.

As a result, the main computer put the data handling unit and all of the telescope's science instruments into safe mode.

Engineers at Goddard Space Flight Center in Maryland were unable to communicate with the SIC&DH for a period of time, a potentially alarming development.

It was a failure by the same device last fall that prompted NASA to postpone the final mission to Hubble. It was delayed about seven months until a backup unit could be prepared for delivery to orbit.

A worst case outcome would have required switching operations from the B side to the A side of the unit and losing critical redundancy, like the older computer. Preserving that redundancy was the reason for replacing the hardware.

But by Monday afternoon, engineers had succeeded in powering the SIC&DH down and back up, and regained communication.

"There was relief when we had it back up and running," said Edward Ruitberg, deputy associate director of Goddard's Astrophysics Projects Division Office.

"Now we have things operating back to normal," he said. "We're getting engineering data from it and it's responding to commands perfectly."

The science instruments won't be brought back online until next week to ensure they are safe while the problem is studied further.

Ruitberg said all the other repairs and replacements made by the Atlantis crew are performing well.

The science instruments are undergoing a months-long period of tests and calibrations before the first new images are released to the public, and scientists around the world resume their galactic observations.

The only setback from this week's computer glitch is to delay that process by about a week, Ruitberg said.

"Everything was right on track up until Monday," he said.

NASA is expected to unveil new images from the refurbished Hubble by September.

Atlantis' crew of seven, led by commander Scott Altman, during five spacewalks installed state-of-the-art cameras and spectrometers, and completed complex in-orbit repairs two older instruments.

They also replaced Hubble's original batteries, launched 19 years ago, plus gyroscopes, thermal blankets and the SIC&DH.

NASA believed Atlantis left the iconic four-story observatory in its best condition ever and added at least another five years to Hubble's life.

IMAGE NOTE: On May 19, an STS-125 crew member aboard the Space Shuttle Atlantis captured this still image of the Hubble Space Telescope as the two spacecraft continue their relative separation, after having been linked together for the better part of a week. During the week five spacewalks were performed to complete the final servicing mission for the orbital observatory.