Black Horizon (The Commonwealth Cycle #1) by Gareth Wood
The Great War of the 22nd century nearly destroyed the Earth. For astronaut Tara Riseman, returning home three hundred and fifty years later, the Earth is not the world she remembers. As she struggles to find some peace in a changed and often hostile environment, Tara becomes embroiled in a conflict that spans the vastness of the solar system itself. From the ocean shores on Earth to the asteroids of the Commonwealth, and the distant icy worlds beyond Neptune, another war is coming.