How The Trouble Began
On June 13th, things weren’t looking good for the Hubble space telescope. The payload computer just went kaput, leading to the main computer and telescope being on safe mode. Though the telescope and other equipment seem to be in working order, carrying out science operations isn’t possible until the payload computer is working again. The team has stopped collecting science data due to the very cause.
NASA has tried almost everything to get back the payload computer working by looking into the command unit, Formatter, and power control unit to check if these components could be the reason for the computer not working. The scientists have been working on tracing the components to switch to the backup modules.
Having a payload computer enables data handling and being responsible for controlling and coordinating all the scientific instruments on the spacecraft. NASA realized something wrong when they got the signal ‘keep alive’ from the payload computer.
Identifying The Cause
Nasa was able to conduct multi-day tests, which included restarting and reconfiguring the computer as well as the backup. The initial tests done by the team showed that those various combinations of the hardware pieces concerning the primary and backup happen to have the same error commands. The team wasn’t able to read or write into the memory and was not successful.
Since individual hardware will face problem like this, the team need to find another culprit. These didn’t yield the expected results, and they had to go back to the drawing board again to check on various other factors, such as the power regulator, which has to provide the constant five volts for it to run successfully. This is usually detected by the secondary protection circuit, which senses the voltage levels when leaving the power regulator. Hence, the team analysed that either the voltage level is low, which may not be acceptable enough, causing the secondary protection circuit to trip or the protection circuit itself has degraded over time and isn’t working has gone into inhibiting state.
Triumph at Last!
Finally, the team could get the backup running again, including the hardware and the payload computer. The halt had caused a major inconvenience to the scientists because it suspended major science data collection useful for research.
The power control unit, the back command unit, and other science equipment that handled data and command and other hardware pieces were switched to alternate interfaces to create a backup. This helped the scientists to take the necessary measures and then work on starting the backup payload computer. There was an additional fight software that was brought to operations mode.
With repair done successfully, the Hubble team has kept a close watch on the hardware, which needs monitoring. They have also started working on retrieving the science equipment, which no longer functions in the safe mode configuration. It may take more time as the team will be working on several procedures to know that the instruments are at stable temperatures to be recalled back. They will also see whether some of them can be recalibrated so that normal operations can happen, and scientists continue with their research.
