With the centrifuge spun up, Grace and Rocky confirm 1 g in the crew compartment and compare gravities; Erid’s is over double Earth’s. Grace explains Earth’s rapid cooling—most humans may die within fourteen years—versus Erid’s slower timeline. Determined to help, Rocky unexpectedly offers two million kilograms of Astrophage, enough for Grace to return to Earth, leaving Grace overwhelmed with relief.

In a flashback on a flight deck, two helicopters deliver six astronauts: prime and backup crews. Stratt’s strict selection rules clash with political realities, but she names Yáo as prime commander, Ilyukhina as prime materials expert, and DuBois as prime science lead, with Shapiro as backup scientist. Stratt assigns Grace to teach DuBois and Shapiro Astrophage biology. DuBois quietly reveals Grace has coma-resistance markers, a fact Stratt hadn’t told him.

Back in the present, three days later, Grace plots a fuel‑conserving transfer to Tau Ceti e, the planet embedded in the widest part of the Petrova line, enabling long-term, repeated immersion for sampling. He details the extreme velocities and minimal fuel needed for the burn, then restores spin for gravity during the coast phase.

Rocky constructs xenonite tunnels and compartments throughout the ship, including an airlock for exchanging items between environments. When asked to name the destination world, Rocky gives the name of his mate; Grace chooses the human stand-in “Adrian.”

Curious about Eridian biology, Grace insists on observing Rocky eat. Rocky privately expels a waste bolus, opens an abdominal orifice to ingest finely shredded food without chewing, then enters an involuntary post-meal sleep. Grace notes the monostome-like system and records the sequence despite the unpleasantness.