system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Mars has no GPS system, and it can't be controlled remotely due to radio delay, so how does the mars rover navigate?
gpt
It's controlled remotely.   There is a delay but that's fine.  We just send the instructions to the rover, along with when to start performing it's actions.  The message gets there at some point and then the rover follows the instructions and reports back afterward on what happened.

It's like playing game of chess by mail.