Chapter 25

Chapter 25 — "Taumoeba-82.5 / Goodbye Rocky"

TL;DR: Grace breeds Taumoeba-82.5 — the Erid-survivable strain — and the two ships finally part: Rocky's vessel turning for 40 Eridani, the Hail Mary setting course for Earth.

Summary: Months of work later, Grace pushes Taumoeba past the 8%-nitrogen threshold and produces Taumoeba-82.5 — the strain that will save Erid. He hands its cultures to Rocky in sealed canisters; Rocky reciprocates with the last of his own gifts: a refilled Astrophage tank for the Hail Mary's long voyage home, plus a small carved Eridian token of friendship. They prep the four Beetles for launch toward Earth (each carrying redundant Taumoeba-35 payloads). They program Rocky's ship for 40 Eridani. They say goodbye in the way two engineers say goodbye — a slow tap-rhythm against the hex-wall, holding for a long time. Then the docking tube retracts, the ships drift apart, and each turns toward home.

Key scenes:

• The Taumoeba-82.5 dish glowing in its lab corner — twin to the Taumoeba-35 dish, now both successes
• The handoff: Rocky's manipulator arm sliding a sealed canister through a transfer port to Grace
• The four Beetles racked in their launch cradles, fueled and waiting
• The two ships separating in deep space, gold thrust plumes against black, a slow farewell

Characters present: Ryland Grace, Rocky

Locations / settings:

• The Hail Mary lab and launch bay
• The docking tube, retracting
• Deep space between Tau Ceti's planets

Visual motifs: two ship silhouettes drifting apart with gold thrust gestures behind each (the cover's gold-on-black DNA in pure form), the four Beetles as a row of small armored shapes, the carved Eridian token as a hard small object on Grace's gloved palm, the docking tube retracting like a closing iris

Emotional tone: triumphant, mournful, mission-completing, full

Confidence: high — Taumoeba-82.5 and the goodbye between Rocky and Grace are pivotal beats.