Saturday, July 17, 2021

WHY ITS CALLED 'BACKUP' HARDWARE
It Lives! 
NASA restores Hubble with a switch to backup hardware
July 17, 2021 

The much-beloved Hubble Space Telescope looks like it will be able to resume operations soon, after a month of nail-biting issues with its hardware which caused all of its science instruments to switch into safe mode. NASA engineers were able to switch to backup hardware onboard the telescope and are hopeful that Hubble should be able to resume its science operations shortly.

The problems began when the instruments switched to safe mode on June 13, due to a failure of the computer which controls them. Identifying the particular component which was causing the problem took some time, but eventually the issue was tracked to a piece of hardware called the Science Instrument Command and Data Handling (SI C&DH) unit and its power unit, the Power Control Unit.
The Hubble Space Telescope is deployed on April 25, 1990, from the space shuttle Discovery. Avoiding distortions of the atmosphere, Hubble has an unobstructed view peering to planets, stars, and galaxies, some more than 13.4 billion light-years away. NASA/Smithsonian Institution/Lockheed Corporation

This week, the engineers switched from the original hardware of these two units to the backup hardware. Most of the hardware in Hubble includes backup versions, in case a problem should occur as it did in this case. However, switching between the two isn’t as simple as flicking a switch, as it requires powering down other components as well and ensuring that the changeover can be made without causing any further problems.


The good news is that the switch to backup hardware was successful, as NASA described: “The switch included bringing online the backup Power Control Unit (PCU) and the backup Command Unit/Science Data Formatter (CU/SDF) on the other side of the Science Instrument and Command & Data Handling (SI C&DH) unit. The PCU distributes power to the SI C&DH components, and the CU/SDF sends and formats commands and data.”

With the main changeover made, the engineers also made changes to other pieces of hardware as well: “In addition, other pieces of hardware onboard Hubble were switched to their alternate interfaces to connect to this backup side of the SI C&DH. Once these steps were completed, the backup payload computer on this same unit was turned on and loaded with flight software and brought up to normal operations mode.”

Now, the team just needs to check that everything is working as it should, and then they can bring the science instruments out of safe mode and calibrate them before Hubble can resume its scientific operations. This is estimated to take a few days, so hopefully, Hubble will be back up and running next week.

NASA says Hubble telescope is back after computer glitch fixed


On April 25, 1990, the Hubble Space Telescope was deployed from the cargo bay of space shuttle Discovery. Hubble, pictured here during its release, has one of its two solar array panels deployed while still in the grasp of Discovery's remote manipulator system. NASA/UPI | License Photo


July 17 (UPI) -- Engineers at NASA say they have fixed a computer problem that had sidelined the Hubble Space Telescope for more than a month.

The space agency said in an update issued Friday it had repaired a payload computer problem by successfully switching to backup hardware on the aging telescope and have re-established communications with all of its instruments.

"The switch was performed to compensate for a problem with the original payload computer tat occurred on June 13 when the computer halted, suspending science data collection," NASA said.

The Hubble team "is now monitoring the hardware to ensure that everything is working properly," it added.

Meanwhile, engineers are also seeking to switch Hubble's science instruments out of their "safe mode" configuration -- a process expected to last into Saturday "as the team runs various procedures and ensures the instruments are at stable temperatures."

Scientists will then carry out initial calibrations before resuming normal science operations.

The payload computer, part of Hubble's Science Instrument Command and Data Handling unit, or SI C&DH unit, controls the telescope's many scientific instruments. When it froze, Hubble's instruments automatically halted operations and went into "safe mode."

After weeks of investigation, engineers at NASA traced the problem to Hubble's Power Control Unit, or PCU, which is also located in the SI C&DH unit.


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