"The gyro that failed had been exhibiting end-of-life behavior for approximately a year, and its failure was not unexpected", the agency said in its statement.
NASA replaced all six of Hubble's gyroscopes in the final 2009 servicing mission.
"Built with multiple redundancies, Hubble had six new gyros installed during Servicing Mission-4 in 2009". The space agency still hopes that it can recover the third enhanced gyroscope and resume normal science operations.
While the telescope is not expected to be at risk of being permanently out of order, two of the four gyroscopes used to direct the telescope towards its targets in the sky have failed.
To operate optimally, Hubble needs three operational gyroscopes.
Only two of those enhanced gyros are now running.
The Hubble Space Telescope has shut down and gone into protective "safe mode" after one of the gyroscopes which keep it in place failed on Sunday, team members said.
But when the telescope's operators switched the instrument to running on all three enhanced gyroscopes, one wasn't working quite as well as it should have been.
NASA scientists are desperately trying to fix the Hubble Space Telescope, which is now pointing the wrong way because of a technical fault. Staff at NASA's Goddard Space Flight Center and the Space Telescope Science Institute are now performing analyses and tests to determine what options are available to recover the gyro to operational performance.
'First step is try to bring back the last gyro, which had been off, and is being problematic'.
While NASA says that reduced-gyro mode would have "relatively limited impact on the overall scientific capabilities", some astronomers are concerned that the reduced-gyro mode could adversely affect some types of observations, such as of solar system objects, that require the precision of three-gyro operations.
"We'll work through the issues and be back", she promised.
Launched into deep space in 1990, the large, long orbit telescope is packed with instruments like cameras, spectrographs and interferometers to clear up mysteries of the universe.