DIASPORA came out in 2010 and is based on the FATE v.3 rule set (before Fate Core). [If someone had the oldest printing of the book or .pdf, there is an errata file from vsca.ca] Fate itself is quite a departure from the number/rolling RPG systems of the past, but by careful description of elements which matter to a hard science-fiction story, DIASPORA offers a satisfying framework. Like all FATE-derived games, it dispenses with the uninteresting minutiae of a game.
The rules are well-organized, but those unfamiliar with FATE may want to pick up the FATE Core System because there the rules were EXTREMELY well-organized with side-bar reminders and page-number references throughout, to help people understand the new FATE concepts. Then you can work back to the slightly older version of DIASPORA.
Diaspora incorporates rules to handle Social interactions and Platoon-level engagements (cough ALIENS cough) as mini-games within the overall structure. The star-systems are generated in a "cluster" system postulating that it is more difficult to get to the next cluster of stars than to travel between the home-cluster. Obviously this will not work with the warp-anywhere fiction settings like Star Wars.
The artwork is a little sparse, though, and could have been integrated to be relevant to the rules examples.