One of the three working gyroscopes (three have already failed0 on the Hubble Space Telescope experienced repeated problems in mid-November, and has now put the telescope in safe mode while engineers trouble-shoot the problem.
Hubble first went into safe mode Nov. 19. Although the operations team successfully recovered the spacecraft to resume observations the following day, the unstable gyro caused the observatory to suspend science operations once again Nov. 21. Following a successful recovery, Hubble entered safe mode again Nov. 23.
The team is now running tests to characterize the issue and develop solutions. If necessary, the spacecraft can be re-configured to operate with only one gyro. The spacecraft had six new gyros installed during the fifth and final space shuttle servicing mission in 2009. To date, three of those gyros remain operational, including the gyro currently experiencing fluctuations. Hubble uses three gyros to maximize efficiency, but could continue to make science observations with only one gyro if required.
The long term plan when the telescope only has two working gyros, assuming no improvised maintenance mission is flown to Hubble to give it new gyroscopes, is to work with only one (treating the second as a back-up) in order to extend the telescope’s life as long as possible.
And though it is true that Hubble could continue to do science with only one gyro, images from that point will likely not be as sharp, and thus will end more than three decades of imagery that changed our perception of the universe.
The Chinese 2-meter Xuntian optical space telescope, now scheduled for launch in 2025, will likely then replace Hubble as the world’s top optical telescope. American astronomers better start learning Chinese, assuming China even allows them access. They will not have a right to complain, however, as it was their decision to not build a Hubble replacement, in their 2000, 2010, and 2020 decadal reports.
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