The Lost Stars #1:Tarnished Knight by Jack Campbell

The authority of the Syndicate Worlds’ government is crumbling, and civil war and rebellion are breaking out, despite brutal attempts to suppress disorder. In the Midway Star System, leaders must decide whether to remain loyal to the old order or fight for something new. Betrayed by his government, CEO Artur Drakon launches a battle for control of Midway. He is assisted by an ally he’s unsure he can trust, CEO Gwen Iceni. While she controls the mobile fleet, she has no choice but to rely on “General” Drakon’s ground forces to keep the peace planet-side. If their coup is to succeed, Drakon and Iceni must put their differences aside to defend Midway against the alien threat of the enigma race — and to ferret out saboteurs determined to re-establish Syndic rule…