The Hubble Space Telescope is headed for recovery due to an error it switched to safe mode in late October. Three of its four (active) devices are now back up and running as of last week, and no new problems have arisen since the first error was detected.
The problem began on October 25, when an error occurred that resulted in the loss of some data synchronization messages. To keep instruments safe from potentially dangerous mis-commands, the telescope automatically switches itself to safe mode. This is just a mode of basic operation in which all the equipment is turned off.
When the error was discovered, NASA engineers began to analyze the problem and slowly turn on the instruments, one by one, to make sure they could do it safely. In our last update on Hubble, we described how the team had turned on Hubble’s advanced camera for the survey and how they plan to turn on other instruments. Since then, the team also turned on the Wide Field Camera 3 instrument on November 21, which captures the many space images for which Hubble is famous.
“The team chose to restore the most commonly used Hubble instrument, Wide Field Camera 3, which represents more than a third of the spacecraft’s observation time,” NASA wrote in a statement. Update, “Engineers also began preparing for changes in equipment parameters, testing the changes on the ground simulators. These changes will allow devices to handle multiple missed synchronization messages, while continuing to operate normally if they occur in the future. These changes will first be applied to another instrument, the Cosmic Origins Spectrograph, to protect its sensitive far-ultraviolet detector. It will take the team several weeks to complete the test and upload the changes to the spacecraft. ,
This week, the team put their plan into action and also retrieved the Cosmic Origins Spectrograph, which showed no further synchronization problems. That means the only instrument to be turned back on is the Space Telescope Imaging Spectrograph, although NASA has yet to share when it plans to try to get it back online. NASA also announced that it is considering making software changes that will allow the devices to continue working despite some lost synchronization messages, to prevent this problem from happening again in the future.