On April 23, 2024, just one day before the thirty-fourth anniversary of its launch, the Hubble Space Telescope was launched. entered safe mode, halting scientific operations. NASA announced this a little while ago, explaining that the cause of the safe mode is to be attributed (once again) to a problem with one of his gyroscopes.
Gyroscopes measure the speed of the telescope’s rotation, and are part of the system that determines the direction in which it points. There are currently three active on Hubble.
The telescope automatically entered safe mode when one of them gave erroneous readings. This is the same gyroscope that already in November 2023, three times in a row, had forced Hubble to interrupt its activities. NASA is currently working to resume science operations as soon as possible.
Another safe mode
During the fifth and final Space Shuttle service mission, in 2009, they were installed aboard Hubble six new gyroscopes. These are small cylinders with a float inside, which spins thousands of times per minute. A fluid helps the float spin effortlessly and without interruption. Two tiny wires, each thinner than a human hair, measure any change in rotation and turn it into an electrical signal. The signal is fed into computers, which tell the telescope’s reaction wheels how and when to move.
The gyroscopes therefore act as an ultra-accurate balancing system, which helps the telescope move as precisely as possible. Currently only three of the six installed in 2009 are operational. If it proves necessary, Hubble could continue the observations even using only one.
The gyroscope which is currently malfunctioning had already shown several signs of failure last November. Even then he gave back incorrect readingswhich automatically activated the safe mode.
NASA is currently working to identify potential solutions. One of these could be reconfiguring the entire satellite to work with just one gyroscope, turning off the faulty one and keeping the third still functioning one as a reserve.
