Hubble Space Telescope is back in the game after NASA fixes gyro glitch

No repair mission required – for now

The Hubble Space Telescope is expected to resume science operations on Friday, after a gyroscope glitch forced NASA to suspend astronomical observations for weeks.

"After analyzing the data, the team has determined science operations can resume under three-gyro control," the US space agency confirmed in its latest update. "Based on the performance observed during the tests, the team has decided to operate the gyros in a higher-precision mode during science observations. Hubble's instruments and the observatory itself remain stable and in good health."

Launched in 1990, the telescope has been serviced multiple times over its decades-long lifetime. In 2009 Hubble was equipped with six new gyros. Only three remain operational.

Gyros measure how fast the telescope turns, and help it stay fixed onto a cosmic target as it orbits in space. One of them began behaving oddly, however, leading to faulty readings – so Hubble automatically entered safe mode on November 19.

NASA initially managed to fix the issue, but the problem returned again and again. By November 23, Hubble had entered and exited safe mode two more times and engineers decided to run more tests to try and come up with a better solution. Subsequently NASA appears to have found a better system and the 'scope is expected to resume operations on December 8 and hopefully keep going for a while longer.

Despite its 30-plus years in space, Hubble should be able to continue observing distant stars and galaxies for the foreseeable future – even if it loses a gyroscope or two.

"To date, three of those gyros remain operational, including the gyro currently experiencing fluctuations. Hubble uses three gyros to maximize efficiency, but could continue to make science observations with only one gyro if required," NASA explained.

The instrument should be able to keep studying stars and galaxies and analyze their light in visible and ultraviolet wavelengths until the end of this decade, and maybe into the early 2030s.

But the telescope is slowly drifting from its intended orbit – currently at about an altitude of 525 kilometers above Earth's atmosphere. It's expected to drop to 500 kilometers by 2025, and at this rate will be drawn down and reenter Earth's atmosphere and be destroyed by the mid 2030s – unless a rescue mission is carried out.

NASA hasn't quite decided on what it will do before then, but has suggested it might attach a propulsion module – either to help the Hubble execute a controlled reentry so it's destroyed over the Pacific Ocean, or boost the telescope higher into orbit so it can continue operating. ®

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