For those who've always wanted to be a living member of a starship crew, PULSAR: Lost Colony is a reasonably good pick and it's nearing release.
Just recently, they put out Beta 21 which includes some more end-game content for the Colonial Union faction. They say the next major updates will focus on end-game content for the W.D. Corporation and Alliance of Gentlemen factions.
The rest shouldn't take as long, as while they were building this lot they say they've created a set of tools to allow them to do it quicker which sounds interesting. That's all that's in, there's quite a bit more exciting additions included in Beta 21. They've included new weapons, a new enemy spawning and respawning system to make exploring planets more interesting, a new system is in for special timed missions to add a bit of tension, there's five new creatures to find and so on.
You can see their latest development video below:
I've played it personally a few times and it is quite interesting. It has a lot of fun ideas and a vast amount more content since I last played it properly so it's likely even more fun now. There's really not many games like it supported on Linux!