Lena Voss - Female, 34. Station chief of Halcyon Outpost. Guarded, precise, dryly funny. POV character. Lost her brother in the Kepler disaster and blames herself. Speaks in short, clipped sentences and notices people's hands.

Theo Marsh - Male, 29. Engineer and Lena's second. Warm, talkative, optimistic to a fault. Secretly forging maintenance logs to hide how badly the reactor is failing. Calls everyone "chief."

Dr. Ada Reyes - Female, 51. Station physician. Calm, blunt, keeps everyone honest. The moral center of the crew. Distrusts the corporation that owns Halcyon and says so.

Cole Bryant - Male, 41. Corporate liaison stationed on Halcyon. Polished, evasive, always recording. Wants the reactor failure kept quiet. Not quite a villain — a man following orders he's ashamed of.