If you don't mind something more OSR, Stars Without Number is a good sandbox space game. I've played it a couple of times and enjoyed it.

get into space RPGs. Anyone got any recommendations?

I played a lot of Fading Suns at the start of the century, we're closer from Dune/Babylon 5 than from Star wars or Star treck in term of concept. The game isn't new (well there was a 4E released recently), and Is a game from the late 90's whose authors worked on Werewolf the Apocalypse this simple sentence tells a lot about the game (Faction who hate each other, imminent doom and more) if it's your stuff go for it.

I played a couple of one shots of Alien and Coriolis, worked fine but I don't know enough the game to have a hard advise on it

and as I said, I plan a Mecha campaign, Lancer seems to combat/crunch heavy so I plan to try Beam saber soon