The intro to an original space campaign that I never ran. It would have used GURPS Space for the rules.
Mankind has reached the stars only to find Earth. Birds flying through distant skies, fish swimming unknown seas, and dinosaurs ruling unexplored continents. On a hundred worlds are found the children of the Earth; an Earth of sixty-five million years ago.
Man has outgrown his cradle and now wonders who and what scattered the seeds of the Earth throughout the stars. He are forging a new life among the stars but old fears and conflicts still threaten.
The year is 2403 and this is their story.
Basically the premise was that inhabitable planets were discovered around nearby stars and by the 21st century several slower than light colony ships were sent out to colonize. They could reach up to 1/10th light speed. Earth suffered a collapse (the exact nature I never settled) and the colonies were cut off. A hundred years later FTL travel discovered (a warp drive) and the colonies and the new nations of Earth expanded throughout near space. It was going be like GDW's 2300 AD with a bunch of national colonies and outposts. Many were served by the United Colonial Guards. Imagine the US Coast Guard being run by a UN style organization and worked with any nation willing to contribute to it's budget.
The "aliens" I designed were the Barron Consulate who were humans who members of a losing faction during Earth's recovery. They had a psionic society. Unlike Traveller's Zhodani their society was dystopian.
There were the Saurians who were sentient dinosaurs more technologically advanced than humans. First contact was made with fringe colonies of the Saurians which not like mainstream Saurian society. Note these are NOT the dinosaurs that left earth 65 million years ago. Rather a group that evolved intelligence on another world.
There were the N'Dassa which was a virus that joined any creature with a higher order nervous system into a hive mind. It exists because so much of the local space was terraformed by the dinorsaurids 65 million years ago. So there a lot of planets with compatible biosphere. Currently it limited to fringe colonies and easily controlled by standard disease control protocols. Doesn't make it less scary and it has been found on multiple worlds that direction of human space.
The big mystery is who were the ancient dinosaurs that left earth 65 million years ago and terraformed everything for hundreds of light years in every direction. On most worlds 65 millions years have obliterated any artifacts due to geological actions and weathering. Even on airless worlds enough time has passed that much of their stuff has sublimated into nothing. However there are a few sites here and there.
The genesis of this setting came when I was reading SPI's Universe and noticed there was a 100 year gap between effective slower than light interstellar travel and FTL travel. So I used the near star map it came with and wrote up a history of the sub-light colonization of near space.