NASA's Hubble Space Telescope has entered safe mode, following the failure of another gyroscope, but its science operations have been suspended, the US space agency said.
Hubble entered safe mode after one of the three gyroscopes (gyros) being used to point and steady the telescope failed last week.
Safe mode puts the telescope into a stable configuration until ground control can correct the issue and return the mission to normal operation.
Scientists are currently performing analyses and tests to determine what options are available to recover the gyro to operational performance.
Till then science operations with Hubble have been suspended.
"If the outcome of this investigation results in recovery of the malfunctioning gyro, Hubble will resume science operations in its standard three-gyro configuration," NASA said in a statement on Monday.
"If the outcome indicates that the gyro is not usable, Hubble will resume science operations in an already defined "reduced-gyro" mode that uses only one gyro."
Although Hubble uses three gyros at a time for maximum efficiency, it can still continue to make scientific observations with just one, NASA said.
Built with multiple redundancies, Hubble had six new gyros installed during Servicing Mission-4 in 2009.
The gyro that failed had been exhibiting end-of-life behaviour for approximately a year, and its failure was not unexpected; two other gyros of the same type had already failed.
The remaining three gyros available for use are technically enhanced and therefore expected to have significantly longer operational lives.
Two of those enhanced gyros are currently running. Upon powering on the third enhanced gyro that had been held in reserve, analysis of spacecraft telemetry indicated that it was not performing at the level required for operations.
As a result, Hubble remains in safe mode.