Iron Psalter of the Starborn Legion

When a newly discovered pulsar corridor makes the outer worlds reachable in weeks, rival houses on a feudalized Earth-and-orbit empire race to raise a disciplined legion for a campaign that will decide who controls humanity’s future. Bound by an oath-recorded “psalter” that logs every order and casualty with unforgiving precision, a brutal commander and a skeptical astrodynamicist uncover a conspiracy that could turn the expedition into an engineered martyrdom.