Hubble Enters Unexpected Safe Mode After Gyroscope Anomaly

NASA’s iconic Hubble Space Telescope unexpectedly entered ‘safe mode’ in November due to faults with one of its gyroscopes. After numerous reengagements, engineers on the ground have placed Hubble back into service twice, but their efforts have been curtailed when the gyroscope has continued to fail. 

NASA said their team is working to conjure solutions for the malfunction, but highlighted that “Hubble’s instruments are stable, and the telescope is in good health”. The gyroscopes calculate Hubbles ‘turn rate’ and identifies which way the telescope is facing. Whilst these systems are in safe mode, all scientific observations are stagnated and Hubble awaits prompts from operators.  

Hubble has been an iconic space observation telescope for over 33 years and has played an integral role in discovering what’s out there in the universe. Both NASA and the European Space Agency delivered Hubble and launched it in 1990, with many discoveries arising as a result. For example, Hubble monitored the outcome of the DART mission, locating 37 boulders that burst from the wreckage. 

What Happened To Hubble?

On 19th November, NASA identified that Hubble had placed itself into safe mode after one of its gyroscopes “gave faulty readings”. The telescope’s instruments are still in working order and there is no immediate threat. After being reactivated by NASA’s operations team, they “successfully recovered the spacecraft” and it recommenced observations the next day. 

However, for a second time, Hubble reentered safe mode and ceased all operations on 21st November. Operators were able to recover the telescope but the unstable gyroscope caused a third shutdown to occur on 23rd November. 

NASA said: “to date, three of those gyros remain operational, including the gyro currently experiencing fluctuations. Hubble uses three gyros to maximise efficiency, but could continue to make science observations with only one gyro if required.”

Fixing Hubble’s Gyroscope

NASA said its operations team are currently running a series of tests to ascertain and “characterise the issues”. They are also developing solutions to underpin the faulty gyroscope so that it does not continuously break down after recovery. 

Nonetheless, NASA said Hubble can – after being reconfigured – operate with a single gyroscope versus its three in current operation. During the telescope’s 2009 final ‘space shuttle servicing mission’, Hubble was configured with a set of six new gyroscopes. Therefore, it’s able to adapt should NASA need to offload the faulty gyroscope. 

Previous Issues With Hubble Falling Out Of Orbit

In May this year, NASA asked space organisations to provide a proposal for pushing Hubble back into optimal orbit. This was due to the space telescope experiencing orbital decay as a result of Earth’s atmospheric drag. To ensure Hubble doesn’t fall out of orbit and come crashing down to Earth, both Astroscale and Momentus hatched a plan to use a mounting vehicle to lift Hubble back into its preferred orbit.