system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do engineers remotely repair satellites and spaceships without physically being there?

I've seen a few news articles of a satellite or spaceship malfunctioning and then days later it is fixed - how?
gpt
You aren't typically looking at physical repairs (although the Space Shuttle did famously repair the Hubble Space Telescope).  Most malfunctions are worked around by changing the control software or invoking backup or alternate control paths.  Sometimes it is as simple as a reboot of the system.

Since engineers on the ground can establish radio communications with the satellite or spacecraft, they can receive information that will help them diagnose the problem.  They then do extensive reviews and meetings to use the data they have and the knowledge they have about the systems and software onboard to figure out likely failure scenarios and mechanisms to work around them (in many cases these scenarios were already planned out and mechanisms incorporated into the satellite or spacecraft at the design phase).

Then they will try out the solutions until one works (or, sadly, until they lose comms or have the satellite/spaceship just stop listening/working).