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Hubble Space Telescope to switch to backup memory module after instrument computer halts

Imagine the service ticket

Computer scientists at NASA are trying to fix the Hubble Space Telescope’s payload computer after the hardware froze due to what's believed to be a degraded memory module.

“The payload computer has four total memory modules and only requires one,” a NASA spokesperson explained to El Reg.

“You can think of it as being similar to a board of memory chips on a laptop that can be swapped out if there’s a problem. The team is currently working to swap the memory module that appears to have a problem. This was done numerous times during testing of the hardware before launch and the operations procedures for doing this are in place. The rest of Hubble is currently working normal.”

The hardy telescope has temporarily paused all science operations and has been in safe mode since June 13, the space agency said on Wednesday.

Ground control said Hubble's main computer did not receive a keep-alive handshake signal from the payload computer, which controls the onboard instruments. Without that signal, the spacecraft’s main computer automatically put all of the payload computer's instruments into safe mode as a precaution. The NASA team attempted to revive the payload system on Monday, though the main computer shut down the instruments again. After studying the diagnostic data, they reckon the problem lies with a bad memory module exposed to elevated levels of radiation, which is causing the payload computer to halt and stop talking to the main computer.

The plan is to get the telescope running again by switching to a backup memory module in the payload computer and leaving that system on for one day. If the payload and main computers can communicate again as expected, the instruments will be turned back on, they should stay on, and thus it can resume its mission. Degraded memory modules are easy to workaround thanks to spare components NASA installed in the telescope before launch.

Eye in the sky

Hubble has been in operation for more than three decades snapping away at the cosmic wonders in the distant universe. Its payload computer is part of a system, dubbed the NASA Standard Spacecraft Computer-1 (NSSC-1), built in the 1980s.

The machine was replaced in 2009 during a servicing mission during which four astronauts also put in new batteries, gyroscopes, and sensors to keep Hubble ticking over. In March this year, an unexpected error also sent the telescope into safe mode. NASA isn’t expecting to reservice Hubble any time soon.

The space agency is supposed to launch its much-delayed James Webb Space Telescope later this year. The JWST views in the infrared, compared to Hubble's optical and ultraviolet captures, and the two together could be a powerful tool, we’re told.

“The Webb Space Telescope will exceed its capability in the infrared once it is launched at the end of this year," a NASA spokesperson said.

"However, no other current or planned general observing NASA mission covers the ultraviolet wavelengths. Therefore, astronomers hope Hubble will work alongside the Webb Space Telescope so the full spectrum of data can be collected on astronomical objects and phenomena. This gives them a more complete scientific understanding." ®

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