Megacity In Space, The Darkness Beyond

In the year 745870, the United Confederation, a nation which controls the Milky Way galaxy, sends a ship named the UCS Excalibur to explore the closest galaxy, Andromeda. The United Confederation was originally formed by humans who originated on the massive city planet, Earth. They had taken the galaxy either diplomatically or by force. The many species had either breeded into humans or died off. The trip will take millions of years but the passengers will be in a cryogenic sleep. The ship is massive and fits 25 million colonists. 10 million of which are soldiers. There will be many stops on the way, and the end goal is Vusara VII, a planet which seems to be habitable for life and a good place to set up an outpost for further expansion by the United Confederation.