They got a little harder at 20, but I remember beating those after a few tries, you just have to take out things like turrents and fighters asap. I know people put them down, calling them rail shooters (which they are) but you have to be alert and quick and even dodge on some of these. Just try new tactics, maybe work on taking out more objectives in one pass on easier ones (like cartel listening station) and you will get better. The first time I beat that one where you have to take out stuff on that cap ship, I made it by just the slimest amout of ship health left. I should probably take my own advice now and go beat that lvl 50 space mission that I died on the end on 5 times in a row.