https://phys.org/news/2018-10-hubble-space-telescope-week-shutdown.html > Hubble's pointing system was compromised earlier this month when an old gyroscope finally failed. The backup did not kick in properly, forcing flight controllers to come up with a fix. Controllers managed to coax the backup gyroscope into operation through a variety of maneuvers and switches. Three gyroscopes need to be working for optimal performance. > Launched in 1990, Hubble has made more than 1.3 million observations of stars, galaxies, black holes and other celestial targets. Some are more than 13 billion light-years away.