The Hubble Space Telescope has been in orbit and helping scientists to learn about the universe for many years now. Hubble has had its share of issues over the years, including one infamous problem with optics that led NASA to send astronauts to repair the telescope. It also suffered another failure earlier this month. This most recent problem had to do with a failed gyro that occurred on October 5.
To make matters worse when NASA tried to switch Hubble to a backup gyro to continue operations, it found that the backup gyro had an issue that caused it to report extremely high rotation rates. NASA says that the rotation rates produced with that backup gyro have reduced since October 5 and are now within an expected range.
That means that Hubble can return to normal science operations with that gyro in use. Hubble’s gyro is a critical component that is needed to help the spacecraft turn and lock onto new targets. On October 16, NASA’s Hubble operations team executed a running restart on the backup gyro. That procedure turned off the gyro for one second and then restarted it before the wheel inside the gyro spun down.
The goal of that operation was to clear any faults that might have occurred when the backup gyro started on October 6, before that startup the backup gyro had been turned off for 7.5 years. Unfortunately, that restart showed no improvement.
On October 18, the Hubble team started the telescope on a series of turns in opposite directions meant to clear blockages that might cause the gyro float to be off-center, producing the high rates the gyro was reporting. After that maneuver, the team noted a significant reduction in the high rates allowing rates to be measured in low mode for periods. On October 19, additional Hubble maneuvers were ordered and appear to have cleared the gyro issue. Rates are now normal in high and low modes. This means Hubble can return to normal operations “soon” according to NASA.