Hubble Trouble May Postpone Shuttle Visit Until 2009

Anne Minard
for National Geographic News

September 30, 2008

A mechanical failure on the Hubble Space Telescope this weekend caused the orbiting instrument to suddenly clam up, according to NASA officials.

The glitch sent mission managers into repair mode just days before the space shuttle Atlantis was meant to make the final servicing trip to the 18-year-old space telescope.

NASA officials now say the mission and its planned upgrades will be delayed and might not happen until at least next January.

Previously slated for October 10, the flight had already been postponed until the 14th to let astronauts recoup training days they missed when Hurricane Ike barreled through Houston, Texas, on September 13.

But just after 8 p.m. EST on Saturday, Hubble put its data-storage computer and science instruments into "safe mode" when it detected errors with its onboard science data formatter, which beams information to Earth.

Mission scientists have not yet pinpointed the cause of the failure, and they were unable to reset the formatter or obtain a memory dump from its computer.

"We've done a fair amount of onboard trouble-shooting," Preston Burch, Hubble manager at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said during a press briefing yesterday.

"All of the testing and all the efforts have indicated that [the formatter] has totally failed."

Temporary Fix

To resume operations quickly, the scientists are leaning toward switching controls to a duplicate data formatter, called side B, already on board Hubble.

The move should get things working again within two weeks, NASA officials said.

But making the switch would leave Hubble without the kind of mechanical redundancy that guards against such failures, noted Ed Weiler, associate administrator of the Science Mission Directorate at NASA Headquarters in Washington, D.C.

Although this is the first time the data formatter's so-called side A has failed, scientists worry that side B has been exposed to the same cyclic heat stress over the telescope's life that may have ruined side A.

Because NASA is retiring the current space shuttle fleet in coming years, anything that breaks on Hubble after this servicing mission will stay broken.

Meanwhile, a complete replica of the entire formatting system has been safely tucked away in storage on the ground since the days when Hubble was designed.

Weiler advocates putting the spare unit through ground-based tests and shipping it to Hubble as soon as it's ready.

"If we could put that in there, we would have an instrument that is fully redundant," he said.

Regardless of whether they use Hubble's backup formatter before the next servicing mission, the scientists are likely to prepare the replica and teach the astronauts how to swap it out.

Switching the units during a spacewalk would take only two hours, leaving astronauts plenty of time to carry out other planned upgrades to the space telescope.

But the soonest the new formatter could be tested and delivered to launch pads at Kennedy Space Center in Florida is early next year, Goddard's Burch said, forcing Hubble to wait at least three months for its upgrades.

Good Timing?

Even as they scrambled to find a solution, Hubble scientists were eager to point out the silver lining.

"If this had to happen, it couldn't have happened at a better time," Weiler said.

"Think about if this failure happened just after the servicing mission. We could have lost the mission."

And despite Hubble's early years plagued with mechanical hang-ups, the space telescope has stayed alive—and sent back data—for 18 years.

"This whole program was declared dead in 1990," Weiler said. "Hubble has a pattern of coming back from adversity."