Noticed this when my AI in her Taipan wouldn't respond to orders. Was about to start going on a rant about insubordination when I realised that she was drifting away, spinning ever so slightly. Switched to the fighter to confirm my suspicions that, yes, the thrusters were dead. Tried to reboot/repair, but it turns out fighters don't get that option. Seems a bit odd to be, especially as there's no way to launch another without your first one either dying or redocking, neither of which are happening when you're drifting 6KM outside the conflict zone