The Hubble Space Telescope entered safe mode over the weekend after a mechanical failure. The glitch makes it harder to aim the telescope.
The orbiting observatory detected an anomaly in one of its gyroscopes Friday and put itself into safe mode, giving ground controllers the opportunity to figure out what’s wrong.
"Very stressful weekend," said Rachel Osten, Deputy Mission Head for Hubble Space Telescope. "Right now [Hubble] is in safe mode while we figure out what to do."
The telescope, launched in 1990 at a cost of about $4.7 billion, uses a series of spinning gyroscopes to help orient Hubble to make observations of the universe and beam that data back to Earth. There are six gyroscopes on the spacecraft, but as the mission progressed, some failed.
Ideally, managers want three operational gyroscopes. Florida Tech’s head of physics Dan Batcheldor said the telescope can continue to make observations with less. “The observatory will still be able to continue to point itself but except you will lose a little bit of choice, for example, the orientation of the observatory in what we call the roll direction.”
NASA said mission experts are working on a solution to the problem. The gyroscope that failed has been examining "end-of-life" behavior for about a year. NASA said its failure was not unexpected.
Batcheldor has worked on about half a dozen Hubble programs. During HST Cycle 15, conducted from 2006-2007, the team only had two operating gyroscopes.
"The way we got around that is carefully designing the observatory program and then essentially waiting the observatory to achieve a particular roll naturally before taking those observations,” said Batcheldor.
Hubble remains in safe mode as mission managers analyze possible solutions. If the team can't get the gyro up and running again, the telescope will remain in a "reduced-gyro" mode, according to NASA, which offers less sky coverage but has a limited impact on the overall scientific capabilities.
NASA’s next large orbiting observatory, the James Webb Space Telescope, is facing cost overruns and launch delays.
