Jun 05, 2024 11:40:00

Four of the six gyroscopes on the Hubble Space Telescope have failed, and it has been decided to switch to 'attitude control mode with one gyroscope'

NASA has reported that one of the gyroscopes on the Hubble Space Telescope has become unusable, forcing it to temporarily suspend operations. As a result, the Hubble Space Telescope has only two usable gyroscopes remaining, but NASA plans to resume observations in a 'single gyroscope attitude control mode.'

NASA to Change How It Points Hubble Space Telescope - NASA Science

https://science.nasa.gov/missions/hubble/nasa-to-change-how-it-points-hubble-space-telescope/

Operating Hubble with Only One Gyroscope - NASA Science
https://science.nasa.gov/mission/hubble/observatory/design/hubble-one-gyro-mode/

The Hubble Space Telescope is equipped with six gyroscopes, three of which are reserved as spares and the remaining three control its attitude.

The gyroscope looks like this:

The gyroscope contains wires as thin as a human hair that deteriorate over time, and as the wires deteriorate the gyroscope will no longer function properly.

NASA replaced all of the gyroscopes on the Hubble Space Telescope with new ones during a maintenance mission in 2009. In addition, an update was implemented to add a 'mode to control attitude with a single gyroscope' to coincide with the replacement with new ones.

Since then, the Hubble Space Telescope has been operated in 'attitude control mode using three gyroscopes' except for a certain period of time, but the gyroscopes have gradually deteriorated and three of the six gyroscopes have become unusable.

Then, on November 23, 2023, a problem occurred with one of the three gyroscopes, and observations were temporarily suspended. Furthermore, on April 23, 2024, the same gyroscope malfunctioned . NASA managed to reset the gyroscope's electronic system and get it to work, but on May 24, 2024, a problem occurred with the same gyroscope, and observations were temporarily suspended.

NASA has determined that the problematic gyroscope is no longer usable and has decided to keep one of the remaining two gyroscopes as a spare and begin operating in 'single gyroscope attitude control mode.' If the mode transition is successful, the Hubble Space Telescope is scheduled to resume observations by mid-June 2024.

In addition, a short-term experiment in 2008 confirmed that there was no problem with the quality of the observation results even in the 'attitude control mode with one gyroscope'. However, since the time required to change the attitude is longer than when using three gyroscopes, there is a possibility that problems may occur in cases where 'you want to observe at a specific timing'. In addition, it will be impossible to observe 'moving objects closer than Mars', but NASA points out that this is a rare observation target for the Hubble Space Telescope.