Hubble set to resume work

The ailing Hubble Space Telescope could be snapping pictures of the heavens again as early as Saturday after engineers fixed one of the problems that has largely shut down the instrument for the last three weeks.

“We spent the last week reviewing,” said Art Whipple, manager of the Hubble Systems Management Office at the Goddard Space Flight Center in Greenbelt, Md.

“Now we’re ready to resume recovery.”

Scientists took the first step Thursday, powering up an instrument that packages and delivers data from the telescope, orbiting 350 miles above Earth, to the ground.

Last week when they did that, two glitches occurred that caused NASA to suspend the recovery operation.

One was a software problem that led to an automatic shutdown.

The other was an electrical short in the power tray.

Goddard engineers have since reconfigured the software.

As for the short, they are hoping it was nothing more than a simple anomaly that occurred because that portion of the tray had sat unused for 18 years in space.

“There does not appear to be any permanent damage” to the instruments, Whipple said in a news briefing from NASA headquarters in Washington.

With the latest adjustments from the ground, the telescope’s wide-field planetary camera should be sending data back to Earth as early as Saturday morning.

This is the second time in a month that problems developed in the data-formatting system.

Previously, the entire system went down.

Engineers were attempting to switch to the redundant Side B of the system when the two new anomalies occurred last week.

Whipple said Hubble scientists were optimistic that they now understand the latest anomalies. On the other hand, “having had this occur, we recognize it could occur again. This is the first time this equipment has been turned on in 18 years.”

All these problems cropped up just as NASA was preparing to launch a repair mission to the telescope.

That mission has now been delayed until at least February.

In five spacewalks, astronauts from the space shuttle Atlantis were scheduled to install an instrument to measure ultraviolet light, as well as a new wide-field camera, and repair failed electronics on the Advanced Camera for Surveys. A new set of gyroscopes to keep the telescope properly positioned in space were also to be installed.

NASA Administrator Michael Griffin has said repeatedly that this will be the final repair mission for Hubble, which has already outlived its expected useful life.

It had been scheduled for termination, but the outcry from Congress and the public, which have been awed again and again by its spectacular pictures, caused NASA to reverse course and approve one more repair.

Pointing out the age of the instruments, however, Whipple said the chip in the main onboard flight computer is an Intel 486, now long out of date in even the simplest home computers.

If all the repairs succeed, Hubble could gain six more years of life.

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john.johnson@latimes.com