The Hubble Space Telescope has been expanding the bounds of human knowledge for more than three decades. That’s not bad for an orbiting installation built in the 1980s that hasn’t gotten a service mission in 12 years. Still, the hardware failures are piling up. After losing several vital gyroscopes several years back, NASA now reports that the observatory is in safe mode after a computer failure.
On June 13th, Hubble’s payload computer stopped working after analyzing a batch of data. This system is separate from the main computer, designed specifically to control and coordinate the science instruments on Hubble. It relays a “keep alive” signal to the main computer when operating normally, but that signal halted on Sunday. In response, the main computer automatically placed all the telescope’s systems into safe mode. It was previously in safe mode for several days in March 2021.
NASA’s first attempt to fix the issue was probably the same thing you would do: They turned it off and on. However, the payload computer soon experienced the same error. The team is currently assessing whether a degrading memory module is the cause of the system failure. The computer is a NASA Standard Spacecraft Computer-1 built in the 1980s, but the current payload computer was replaced during the last Hubble servicing mission in 2009. Luckily, it has several layers of redundancy built-in.
Following the failed restart, NASA activated a backup module. The plan is to let that system run for about a day and then reassess. If everything is still working, NASA will flip the switch to reboot Hubble’s science instruments. Given the robustness of the “Standard” computer, NASA is confident that Hubble will be operational again soon. Hubble is still the only large space telescope humanity has at its disposal, but help is on the way. We’re finally on the verge of launching the massively delayed James Webb Space Telescope.
The Webb telescope will have a much larger segmented reflector, allowing it to see objects with much more detail than Hubble. However, after 20 years of work, the team wants to make certain the spacecraft is in perfect working order before launch. Webb will be heading to the Earth-Sun L2 Lagrange point, almost a million miles from Earth. Hubble is in low-Earth orbit, making service missions possible. NASA recently pushed the Webb launch back yet again. It’s currently on the books for November or December of this year.