A vague timeline at least, a more intricate examination of events would be better. This is an alien culture, a completely different people to Homo sapiens. In fact, the reason these people have stumbled onto a cluster of viable planets around a cluster of stars is because they were terraformed millenia prior, by humans themselves, who are now a vanished people. Not sure how viable it is, but it might be nice for artifacts or ruins from prior human settlement to come up in the background.
The Great War
The Great War (better name possibly to come) is the inter-system conflict that began as tight policial fighting among a group of more or less equally powerful nations on the home world of Mannon in the Rua system. While its actual beginnings are a little vague and no real start date can be picked out, serious fighting has been happening on and off for the past 30 or so years.