Neutral Buoyancy Lab

The Neutral Buoyancy Lab (NBL) at NASA's Johnson Space Center is a gigantic swimming pool large enough to hold a full-size replica of the International Space Station, used to train astronauts for zero-gravity EVAs. In Project Hail Mary, it becomes the site where Ryland Grace tests the IVME (in vacuo microbiology equipment) kit, a set of custom-designed tools for handling Astrophage in space. The NBL's role in the narrative underscores the immense logistical and engineering effort behind the Hail Mary mission, while also revealing Grace's growing competence and the mission's reliance on off-the-shelf, rigorously tested technology.

Purpose and Design

The NBL is a marvel of engineering, a gigantic swimming pool large enough to fit a full-size replica of the International Space Station. It is used to train astronauts on zero-g maneuvering while in EVA suits. Grace is sent there to test the IVME kit, an acronym for "in vacuo microbiology equipment," which was developed after the microbiology community convinced Eva Stratt that the mission needed custom-designed tools. Stratt agreed only on the condition that none of the tools be mission-critical, insisting that all important equipment be off-the-shelf products with millions of hours of consumer testing. The biggest problem for the IVME kit wasn't making equipment that worked in vacuum—though they had to completely redesign pipettes because there's no suction force in space—but the ham-fisted EVA gloves the user had to wear.

Grace's Training and the IVME Kit

During his training at the NBL, Grace wears a Russian Orlan EVA suit, which Stratt selected after experts agreed it was the safest and most reliable. He stands in one corner of the NBL, with the imposing figure of the ISS replica behind him, while two scuba divers float nearby, ready to rescue him in an emergency. NASA had sunk a metal lab table into the pool for him. The tool in his gloved hand is far from perfect but ingenious: it turns the clumsy pawing of an EVA suit glove into fine manipulation at the other end. Grace squeezes a trigger with his index finger to constrict the clamp by 2 millimeters, a different trigger with his middle finger to rotate it up to 90 degrees clockwise, and his ring and pinkie fingers to tilt it forward up to 90 degrees. During the test, he drops vial number three, and the tool's internal microcable wires become tangled, causing the clamp to release instead of tilting. Forrester, the technician, collects the tool to make changes, noting they can try again in a couple of hours.

Narrative Significance

The NBL sequence serves as a microcosm of the entire Hail Mary project: a massive, global effort where even the most mundane tasks require extraordinary ingenuity and testing. It highlights the tension between Stratt's insistence on reliable, off-the-shelf technology and the need for custom solutions for unprecedented challenges. Grace's struggle with the IVME kit—dropping vials, dealing with tangled cables—foreshadows the many EVA challenges he will face alone in space, from collecting the alien cylinder to retrieving the sampler from Adrian's atmosphere. The scene also reinforces Grace's role as a reluctant but capable test subject, a role that will define his entire mission. After the NBL session, Forrester tells Grace he is needed in Building 30 to train Martin DuBois and Annie Shapiro on Astrophage, a task that underscores Grace's unique position as the world's leading expert on the alien microbe.