The court-martial of Bronze Age is held at a fleet base in geosynchronous orbit because Earth International is intensely interested in the case. Captain Neil Scott tries to take sole responsibility for the attack on Quantum, but the prosecution reveals that the crew voted on the decision. Under pressure from the judge, Scott admits that 1,670 crew members, ninety-four percent of the ship, voted to attack, though Scott insists the final order was still his.

Lieutenant Commander Sebastian Schneider, who could have prevented or terminated the attack through the targeting systems, explains that the crew’s realization that they would never return home transformed them. Schneider says that in deep space the individual self collapsed into a survival-driven collective, comparing the ship’s rapid turn toward totalitarianism to Ron Jones’s classroom experiment, The Third Wave. Schneider argues that when humans are truly cut off from Earth, they become psychologically alien to Earthbound humanity.

Commander Boris Rovinski testifies about boarding Quantum after the attack and finding no survivors. Rovinski reveals that the bodies of Quantum’s crew were recycled into Bronze Age’s food supply because the damaged ship could not feed everyone otherwise. The courtroom reacts with horror, but Rovinski explains that, in the moral logic of a doomed ship facing an endless voyage, wasting protein would have seemed unconscionable.

In his final statement, Scott warns that just as fish ceased to be fish when they came onto land, humans who truly enter space and leave Earth behind cease to be human. Scott and six senior officers are sentenced to life imprisonment; most of the remaining crew receive long prison terms, while only 138 are declared innocent. The prisoners are sent toward a fleet prison in the asteroid belt, leaving Earth again despite having come within thirty thousand kilometers of home.

Before departure, Schneider, Rovinski, and other officers return under guard to Bronze Age to help transfer the ship to a new crew. They find that the gardens, holograms, fountains, and other signs of their life aboard have been erased, returning the vessel to a cold warship. During a technical handover, Schneider traps the officers and guard on the other side of a divided cabin and activates the interstellar communications antenna.

Schneider sends a warning to Blue Space: “Don’t come back. This is no longer your home!” A military policeman shoots Schneider dead, but the message reaches Blue Space, which stops decelerating and flees at full acceleration. Earth and Trisolaris, now sharing fear of Blue Space, send Gravity in pursuit with two Trisolaran droplets as escorts; because of distance and acceleration limits, the chase will take about fifty years.