Terminus Cycle: Andlios Legends (Andlios Science Fiction #0.5):

They traversed the cosmos in search of a new home. They found more than they looked for... Two generations lived and died aboard the Omega Destiny and now, after eighty years, home was on the horizon. Everything is going according to plan until Jonah discovers a strange object in space shrouded in mystery, the only clue being a missing cosmonaut. What he discovers not just changes their mission, but human history itself. Time is running out, and it's too late to turn back. Jonah and everyon...