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."
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