Grace wakes to Rocky’s watchful “cultural” habit and prepares for their approach to Planet Adrian. After repeated failures, the spectrometer finally analyzes Adrian’s atmosphere: heavily CO2 with significant methane, which Grace flags as anomalous because methane should photodissociate. They schedule orbital insertion, noting the risk if Rocky’s calculations are wrong.

Insertion succeeds using Rocky’s precise data. Rocky then adapts a tactile camera so he can perceive Grace’s visual feed and begins learning about color. With the External Collection Unit already exposed for nearly a day, they prepare to retrieve their Astrophage sample.

Grace performs an EVA, detaches the sampler, and returns inside. In the lab, he separates and rinses the adhesive from both panels and measures heat output to estimate population. To their surprise, Astrophage totals are the same on both sides, contradicting expectations of higher outbound traffic from Adrian to Tau Ceti.

Examining a slide under the microscope, Grace finds a bustling variety of non-Astrophage organisms within the Petrova line samples. Rocky connects the population parity to predation: some Adrian life must eat Astrophage. Grace concludes Adrian is likely the Astrophage homeworld with a full ecosystem, including an Astrophage predator. They celebrate and commit to capturing a predator to bring home as a potential solution.

Flashback: At NASA’s Neutral Buoyancy Lab, Grace tests in-vacuo microbiology equipment for EVA use with a Russian Orlan suit, troubleshooting a delicate clamp tool. Later, he trains Martin DuBois and Annie Shapiro on Astrophage biology; they candidly disclose their sexual relationship before resuming study, underscoring the mission’s stakes and personal costs.