Dark Galaxy Box Set
by Brett Fitzpatrick
Over the course of three books (Galaxy Dog, Iron Dart, and Sun Chaser) Altia, the most prominent young scientist in the empire, Knave, a young soldier, and Jay, a humble logistics robot, are sucked ever deeper into this rebellion, and then rise to become its leaders. There are plenty of space battles, unknowable aliens, and galactic power struggles in the series.