Star Citizen is Chris Roberts' new game. Chris Roberts is the guy behind Wing Commander, Starlancer, and Freelancer. He had huge ambitions for Freelancer and the game was completely failing to get made so Microsoft kicked him out and got the game done without him. That cannot happen with Star Citizen, because he is self-publishing it based on money people spend on spaceships, so likely the game will never get finished. The single player campaign is called "Squadron 42" and the plan was for that to have come out many years ago, so chances are that will never get finished either.
The ambitions are very high: Star Citizen is an open world MMO where you play as the pilot, rather than the ship, meaning everything from docking stations to cargo to medical evacuations to mining to piracy to bounty hunting to transportation to planet colonization to system exploration is all entirely simulated and immersive.