Try, try again

New(ish) fix for the Hubble Space Telescope

NASA’s Hubble Space Telescope had a rough month. In an on-again, off-again saga of cosmic proportions, engineers encountered more problems while trying to fix an original malfunction. But don’t give up on Hubble yet.

Engineers announced October 23 that the problems were not serious, and that the team will attempt to revive Hubble’s scientific operations once again. The assessment is based on an exhaustive review of the data collected from Hubble as it was faltering on October 16. The Hubble team has received the go-ahead from NASA headquarters to reactivate the science tools through a backup “B” side computer, and the reactivation may take place over the weekend.

“Currently we’re looking at early Saturday morning to be up,” Art Whipple, manager of the Hubble Systems Management Office at NASA Goddard Space Flight Center in Greenbelt, Md., told reporters during an Oct. 23 conference call.

Over the last 18 years, Hubble, from its orbit of Earth, has provided unparalleled views of far-off galaxies, black holes and other cosmic mysteries; the data it sends back have transformed our view of the universe.

Hubble’s observational tools have been silent since September 27 due to a hardware failure that left almost all scientific equipment on board unable to communicate with Earth. Engineers attempted October 15 to circumvent the faulty “A” side science computer, which was responsible for packaging and transmitting data from Hubble’s powerful telescope back to Earth, by switching to a backup “B” side computer.

But the Hubble team ran into some problems after the switch. Although several key scientific instruments, including the Advanced Camera for Surveys, the Wide Field Planetary Camera 2 and the Near Infrared Camera and Multi-Object Spectrometer, briefly functioned through the “B” side after the switch, engineers encountered two anomalies — one in a power supply to the Solar Blind Camera and another in the science computer — during the last stages of reactivation. The glitches sent Hubble’s science equipment back into the dormant safe mode in which they have been since the original failure in late September.

After careful assessment and pouring over what Whipple described last week as mountains of data, engineers concluded that neither anomaly represented damage in the “B” side equipment. The ACS power supply failed because of a solvable timing issue, and the science computer shut down likely because of a short or an open circuit. Whipple points out that these types of electrical glitches are not unexpected when an 18-year-old piece of equipment is activated for the first time. As far as the Hubble team can tell, the malfunctions did not seem to cause damage to any other parts of Hubble either.

In an important first step to resuming science functions, engineers started the science computer aboard Hubble on October 23, although the science equipment remains dormant. As for a planned service mission to Hubble originally slated for October, it has been pushed to February of 2009. “We’re still in assessment of that mission date,” says Whipple.

Laura Sanders is the neuroscience writer. She holds a Ph.D. in molecular biology from the University of Southern California.

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