The Hubble Space Telescope is old. It’s rapidly approaching its 31st anniversary of being launched on its mission to study the cosmos, and while 31 years might not seem like that long, for a piece of machinery orbiting Earth — and enduring all that comes with being exposed to space — that’s a very long time. It’s worked well for a very long time, returning some incredible images and other observations of structures in space, but it isn’t going to last forever, and this week it showed its age.
On March 7th, Hubble unexpectedly shut down its science observations. The automated systems that keep track of the spacecraft’s health triggered the switch, putting the telescope into “safe mode” due to what is being described as “a software error within the spacecraft’s main computer.” Unfortunately, that was just the beginning of the weirdness that Hubble’s handlers had to deal with over the past week.
As NASA explains in a new blog post, The error occurred at approximately 4 a.m. EST. When the Hubble team checked in on the telescope to see what was going on they discovered that something was amiss in a recent update they did to the spacecraft’s software. The change was supposed to help the telescope remain stable despite one of its gyroscopes not being what it used to be. “[The Hubble team] determined that the enhancement did not have permission to write to a specific location in computer memory, which caused an issue with the main flight computer and subsequently caused the spacecraft to enter a safe mode,” NASA says.
NASA says it is already working on a fix for the software issue and will roll back the changes it made in the meantime so that the telescope can get back to work. However, when the team was taking a nice hard look at the spacecraft’s systems they spotted another problem: Hubble’s auto-closing aperture door was stuck open. The door is designed to close if the telescope accidentally points toward the Sun, as this could damage or destroy some of its most sensitive bits. The team confirmed that commands and power were making it to the door’s motor, but nothing was happening. Thankfully, a backup motor is installed for just such a failure, and NASA will now use the backup motor in place of the primary motor.
Phew! So, that’s it, right? Unfortunately, no. As NASA was preparing to return the telescope to its working mode, an “unexpected error” in the Wide Field Camera 3 popped up. NASA isn’t revealing many details about this but says that it will suspend the use of that instrument until it can figure out what is wrong.
NASA really, really wants Hubble to live on for many more years, and to be honest, the agency really needs it to keep working. With the incredible delays and cost overruns of the James Webb Space Telescope (thanks to the repeated failings and incompetence of contractor Northrop Grumman), NASA depends on Hubble in a big way. Let’s hope that whatever issues arise can be fixed.