I don't expect ME/CFS to ever be included in that.

Maybe if said astronaut has others in there helping them and they aren't doing much work at all but I agree with this condition I would not even want to be flying when I'm the one paying for it. Long car rides in for me in general aren't a great experience. I can't drive myself because I can't handle all the tasks on the road at once while paying attention to it properly. I know everyone isn't this severe in the cognitive department but even so I can't imagine piloting a ship is going to be anything but even harder than a car.

People underestimate how bad brain fog can get, if I pace well and avoid enough immune triggers and stay under my PEM load my brain fog is manageable enough to hold a job but I get confused or a little lost in the middle of tasks even so occasionally. If I for example though completely expose myself to all my common triggers, exhaust myself, and throw myself into any stimulating environment with a specific task to do my brain will do things like mix up moving my left and right hand as well as coordinate those movements with connected motor tasks and forget chaining tasks together properly and communication. I'll also frequently just blank out and take too long to know what to do next. I wouldn't last too long if I didn't keep it in line.