Problems with the Hubble Space Telescope
The Hubble Space Telescope has been in orbit since 1990. That's incredible for the high-radiation environment it has to work in. After a shaky start, it's been sending mind-boggling photos back to Earth for more than 30 years.
But a few weeks ago the payload computer stopped.
The computer equipment on board the HST has many levels of redundancies: there are backups for their backups. So the first problem is identifying the component that has failed.
But even after they've found the problem, NASA can't just go up there and start soldering. Since the retirement of the Space Shuttle, they have to do it all remotely. What's currently up there is going to have to do.
What's more, while many astronomers on Earth communicate with their equipment at a distance, remote maintenance is difficult when it might be the remote computer that's gone on the fritz!
There are a few suspect parts. Initially, NASA though it may have been a bank of memory modules that had failed. However, subsequent tests indicate that the central processing module (CPM) might be the problem. However, the CPM communicates to other components through a piece of connecting hardware called STINT, and that may be where the problem lies.
The CPM and STINT were both installed at the time of the last Space Shuttle mission in 2009, but were designed in the 1980s. There are backups of both of these on board, and there are no fewer than three layers of backups for the memory modules.
Once NASA diagnoses the actual problem, it'll be up to the creative minds there to figure out a way to work around the area. With luck, it'll be a simple case of rerouting to a backup piece of hardware. After all, the initial architecture of the system was to enable just this sort of solution.
Ultimately, Hubble will be supplanted by the James Webb telescope. That's due for a delayed launch late this year. So even if Hubble can't be fixed, we won't have to wait very long for the march of science to continue.
Update: more than a month later, NASA still hasn't been able to restart the HST's computer. The scientific community is beginning to think it's game over for Hubble. Vale, old friend.
Another update (late July 2021): Finally, NASA has been able to get Hubble back on line! Who knows how long we've got, but James Webb is still grounded, so we'll take every image we can!