What Happened to the Hubble Space Telescope? NASA Update on Failed Gyroscope

NASA's Hubble Space Telescope has brought us images of distant galaxies, comets breaking up, black holes and more during its time in space. On October 5, NASA was made aware that the craft automatically went into safe mode around 6 p.m. EDT. The craft did so because one of the three gyroscopes on the telescope failed, according to NASA.

When the gyroscope failed, the craft immediately went into safe mode to put the craft in a stable configuration. The gyroscope that failed was one of those used to point and steady the telescope, according to NASA. Once in safe mode, the ground control can try to diagnose the problem and solve it to get the telescope back up and normally running.

A week after the failure of the gyroscope, NASA was still working to resume operations on board the Hubble telescope. Part of the delay had to do with the fact that one of the backup gyroscopes, installed with redundancy in mind, also wasn't functioning properly once it was turned on.

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The Hubble Telescope went into safety mode on October 5 after a gyroscope failed. NASA

That backup gyroscope was reporting rotation rates that were higher than they should be. So not only was NASA examining the cause of the first gyroscope's failure, but it is also looking into the malfunction of the second one.

What researchers discovered was that the backup gyroscope is actually tracking the telescope's movement correctly but then reporting the rates falsely, according to NASA. The rates that are being reported are too high for the gyroscope to be able to measure the small movements of the telescope, those measurements of small movements are needed to determine whether the telescope is locked onto a target and remaining still.

Hubble was launched in 1990 out to space from the Discovery space shuttle. Since then it has undergone several servicing missions to upgrade it, including the installation of extra gyroscopes in 2009.

When Hubble captures images of objects, those objects frequently appear faint, and it's imperative that the telescope stays still while capturing such small objects. It's made 1.3 million observations while in low Earth orbit, completing one orbit around the Earth every 95 minutes or so, according to NASA.

Those observations and the science operation of the telescope were suspended while NASA was working to discover the anomaly of the gyroscope and hopefully adjust the operation back to normal. If that is unsuccessful, NASA plans to put the telescope into one-gyroscope operation, which would still allow it to function for years collecting further science.​