We all have those moments where we need to have extensive repairs or upgrades that take time, plenty of time for a game that is, so we all need ways to pass the time while engineers do their work. The following is some of the stuff I do to pass time, but UCSE and all previous and future variants of it have almost infinite possibilities of what you can do. So get creative if you want.
One thing I do is take a tour of the galaxy on a shuttle. I get a marine as a pilot, load up a buggy (you can load a tank if it makes you feel safer, more confident, bigger downstairs, etc.)and I go cruising. When in space I usually fly the shuttle myself, but if I have the need to explore a moon or planet, I switch the shuttle to autopilot, turn on Tacops comp, and order the shuttle where I want to be dropped off in my OC and where the shuttle will wait for me. When I hit the ground, drive around and have fun, explore, of even conquer a base if you feel like it.
Another thing I do to pass time is plan massive ground ops if I have control of my launch bay and get rid of an insurgent base (I'm Terran Military usually) or two, depending on how much time I got until my ship is fixed. I might even just go ahead and jack a tank or fighter instead of watching others have fun by teleporting my AE next to any vehicle I choose. I prefer teleporting to a building and sniping any infantry that would kill or bug my marines on ground ops.
The next few ways to pass time are the most productive money wise. First the simple one, get in a fighter and take down some enemy freighters, and use a shuttle to pick up the pods or tow back the disabled ship. The slightly more complicated way is to deploy Mining Drones to the closest moon or planet, then you can raid nearby ships like I said above. Doing these things yourself is more fun than ordering someone else to do it for you, unless you think you need to be aboard just in case of emergencies. Up to you.
So far I was assuming you were playing a commander of a ship, but if you are a planetary defence pilot or marine, check out your surroundings, get in a DJP and check out other bases, essentially keep moving and hope that a battlecruiser will show up and make your day. Nothing much more to do in the enlisted careers (I'm going into the Army, and I hope I don't see action, but this is a game, action is its BLOOD! BRING ON THE PAIN!!) and if you get bored as an enlisted man, be a commander, much more to do.
Any other ideas are welcome.