Project Hail Mary

Back in the present, Grace activates the Hail Mary’s navigation system and learns that the journey will be complete in five days. Once the Astrophage-powered engine is turned off, Grace will be able to use the “Petrovascope” to search for the signature infrared light emission of Astrophage around Tau Ceti. Grace does the math and realizes that, because of relativity, he has been traveling for three years while at least 13 years have passed on Earth. If Grace is able to successfully send the Beetle probes back, Earth will still have to survive a total of 26 years with a dimming sun. Grieving his crewmates and struggling with the psychological burden of bearing responsibility for the survival of the human race, Grace decides to familiarize himself as much as possible with the ship as a distraction.

In flashback, Grace builds an Astrophage breeding device. Stratt asks Grace his opinion on the dilemma of staffing the three Hail Mary crew members. The cramped quarters and psychological stress of certain death are likely to lead to severe depression and a high risk of suicide. The astronauts could be put into four-year comas, but the health risks are too high. Stratt has research from a failed company in Thailand that attempted to induce comas in chemotherapy patients for the duration of their treatment. The research identifies a genetic sequence that causes coma resistance in humans, but only one in every 7,000 people has the DNA marker, meaning the applicant pool is severely limited. Grace tells Stratt she just wants him to confirm what she already knows: She can’t mitigate the risks of leaving the crew awake, but humans do have time to develop coma technology, and she should only select applicants with the coma-resistant genetic marker.

Back in the present, Grace’s memory is improving. He catalogs the lab, explores the extensive reference materials in the lab computer, and learns how he will eventually launch the Beetle probes. As the Hail Mary reaches its destination point, the engines shut off, and Grace adjusts poorly to zero gravity. He is finally able to turn on the Petrovascope, which was useless while the Astrophage-powered engine was on.

Grace uses the Petrovascope to identify a Petrova line stretching from Tau Ceti to one of the star’s planets, but an unidentified object partially obscures his view. There is an alien spaceship within a few hundred meters of the Hail Mary.

Grace names the alien spaceship “Blip-A” after the readout on the monitor and calculates that the Blip-A is roughly three times larger than the Hail Mary and constructed from broad, flat faces like a many-faceted diamond—a poor shape for efficient flight or containing atmospheric pressure. The Blip-A is also Astrophage powered, displaying a steady glow on the Petrovascope. Grace flashes his engines to signal to Blip-A, which signals back, indicating that there is intelligent life aboard.

The Blip-A pulls alongside the Hail Mary, and Grace makes out a hull robot mounted on the alien ship. The robot tosses a cylinder to the Hail Mary, and Grace determines it will reach him in 40 minutes, giving him just enough time to prepare for a spacewalk to retrieve it. Grace speculates on whether the aliens will be friendly but feels reassured by the efforts the aliens are taking to communicate.

Grace finds that he is very comfortable on the spacewalk, or EVA, and assumes he must have some astronaut training. He retrieves the cylinder sent from the Blip-A, which is the same mottled tan color as the Blip-A’s hull and about the size and shape of a coffee can. Back inside the Hail Mary, the cylinder is too hot to handle despite having traveled through freezing cold space and reeks of ammonia. Grace leaves the cylinder in the airlock to cool and let the ammonia smell dissipate and tries to remember how to use the lab equipment on the ship, which will only work in Earth’s gravity.

In flashback, Grace travels with Stratt to Geneva, Switzerland, to meet Dr. Lokken, a Norwegian climatologist. Lokken and Grace are initially combative, as Lokken has a poor opinion of Grace from his controversial paper, and Grace and Lokken argue about whether Earth life and Astrophage share a common biological ancestor.

Lokken has been trying to reach Stratt after hearing that Stratt intended to develop special lab equipment to work in zero gravity. Knowing that the rushed development of specialized equipment is likely to fail or have inaccurate results, Lokken proposes that the Hail Mary be designed to divide in half and transform into a giant centrifuge, creating the gravity necessary for the more reliable, existing lab equipment to function properly. Grace agrees that Lokken’s transforming centrifuge ship design is better than risking poorly designed zero-gravity versions of very sensitive equipment. Stratt drafts Lokken to design the Hail Mary, despite her protests.

In the present aboard the Hail Mary, Grace locates the controls for transforming the ship into a centrifuge to achieve Earth gravity, or 1 G. After transformation, Grace notices that the Blip-A is mimicking the Hail Mary’s spinning and jokes that he is glad to be a part of the “first miscommunication” with intelligent extraterrestrials.

In the lab, Grace determines that the alien cylinder is made of pure xenon, which should be physically impossible as xenon is a gas at room temperature. The xenon cylinder is impenetrable, but Grace notices a seam and is able to unscrew the lid, albeit in the opposite direction he expects. Inside the cylinder is a tiny scale model of the local star system, with one star and a planet having a Petrova line arcing between them. Grace determines from the model that the aliens are from a planet near the star 40 Eridani, which is also experiencing an Astrophage infestation. Grace names the alien race “Eridians” and the solid xenon material “xenonite.”

Grace solders a line between Tau Ceti and Sol (Earth’s sun) on the model and adds a paraffin wax Petrova line arcing toward Venus, hoping to communicate that he and the Eridians are at Tau Ceti for the same reason. Grace transitions the Hail Mary out of centrifuge mode and suits up to do another EVA and throw the cylinder back to the Blip-A. Several hours pass before the Blip-A tosses back a new cylinder, this time aiming the delivery right into the Hail Mary’s airlock, making things easier on Grace, who waves to the Blip-A’s hull robot. Inside the new cylinder is a model of the Blip-A and the Hail Mary connected by a tube. Grace realizes that the aliens want to meet.