One of my dream occupations used to be Paranormal Investigator. The reason being there's no licensing or regulations to the field, no requirements and the main quality looked for is an earnest manner of speaking (I can do that.) I'd go to people's houses or wherever and explain to my clients what was causing their 'haunting', banging pipes, raccoon gang war on their roof or whatever and set their minds at ease. Pondering this I decided against it for a couple of reasons.
The first is that I'm not handy at all. If it can't be fixed with duct tape I'm out of options. So I'd be the last person to be able to explain about pipes banging or electrical wiring. The second reason is that I'm sure a sizable fraction of my clients would want to be told they have a a real 'live' ghost. Third reason was that I might actually run into something paranormal and I'd really feel badly telling my client, "Looks real. I'm gone. I guess you're screwed." That always bothered me about these investigation shows. It's almost like going to a doctor and being told no you aren't crazy, you're sick and being sent away without treatment.
I'm not a firm believer in the supernatural. I firmly believe in the preternatural: things we can't explain yet. Hell meteors were an unexplainable phenomena a few hundred years ago. Rocks falling from the skies? Ditto for rains of frogs or fish and today we have the profitable and enjoyable Sharknado movie franchise! So my approach to an event that seems impossible is usually to say "What can be happening here?" and not thinking someone may be a headcase.
Needless to say ghost stories still scare the crap out of me. I've had a couple of odd things happen to me that were probably just very weird coincidences that couldn't have been timed better if my life was a movie. I retain my skepticism.
My ghost drive idea has some happy fall out (until the psionic in the crew goes nuts and starts playing with the first aid kit in ways that make you rethink re-enlisting.)
Ghosts replace the rule of cool for starfighters (although I think the ghost drive is pretty cool.) You can't have a reactionless drive without a spirit and you sure as hell are not going to trust them to drive a missile bus without a psionic minding them. Life (and death support) both become necessary.
Forget those heat radiators/sinks/glowing thrusters (wait keep the glowing thrusters just make them green.) That sudden chill in the cabin can cool you and your systems down. Your friendly spirits may be able to provide a degree of stealth if you let them roam the ship.
AI may require a very high tech level but if your spirit containment can be made small enough why not let a friendly spirit work your cargo loader or security bot?
If these are spirits of the deceased and they remain rational with intact memories can we install them in robot bodies and continue their physical existence (talk about a prosthetic device!)?
Not me. But someone is going to try it.
Using technomagic is always a slippery slope. I use ghosts or spirits to duck old man Newton and thermodynamics and where will it end? Can spirits communicate with other spirits at FTL speeds? Are they a useful adjunct to conventional sensors? Can they read minds? Can they animate the dead?
I'm one of those people who hate movies where the ghosts can do anything and are godlike. Make it eternal night for the humans. Manipulate time and space to make fleeing flesh bags return to the scene. It's as bad as wantum physics in SF. When you make up the rules you need to tell the story you wind up with no rules and damned little story.