NASA has successfully fully restored Hubble to full operation, and all four of its active instruments are back online and collecting science observations.
Hubble went down for the second time in 2021 in late October. Scientists discovered a loss of specific data synchronization messages, which prompted them to take the legendary telescope offline and into “Safe Mode” so engineers could investigate what went wrong. The team was focusing its efforts on isolating the exact problem on hardware that commands the instruments, specifically the circuitry of the Control Unit which generates synchronization messages and passes them onto the instruments.
The team was able to revive Hubble’s most heavily used camera — Wide Field Camera 3 — in late November. The camera represented more than a third of the spacecraft’s total observation time, and its successful revival made a full recovery of the telescope look promising.
Today, NASA announced that it was able to fully activate all four of its instruments on December 6 and the team has not detected any further synchronization message issues since monitoring began November 1.
NASA says that the team will continue to work on developing and testing changes to Hubble’s software that will allow them to continue operations even if they were to encounter lost synchronization messages in the future. The first of these changes is scheduled to be installed on the Cosmic Origins Spectrograph in mid-December. The other instruments will receive similar updates in the coming months.
Hubble is challenging to maintain because it is no longer possible to work on the telescope directly. The shuttles that used to fly periodically to the telescope to perform repairs were retired in 2011, and now the only way for NASA engineers to troubleshoot and repair the telescope is through remote software fixes.
Hubble had been operating continuously for 31 years before its two hiccups in 2021. In June, Hubble went offline for almost a month due to a glitch in its payload computer, which could have taken the telescope down for good. This second issue lasted just over a month, but it two managed to be resolved remotely. For now, Hubble is back to work observing the cosmos. Hubble’s successor, the James Webb Space Telescope, is scheduled to be launched no earlier than December 22.