Project Hail Mary

An unnamed man wakes up in a sterile, round room with total amnesia, tended to by a computer and robotic arms. He is connected to tubes in an oval bed alongside two other patients who are long-dead. As he regains physical mobility and cognitive function, he discovers that despite his confinement, his body remains muscular and well-toned. He experiences fragmented memories, including a specific email from a Dr. Irina Petrova regarding a mysterious infrared line in the solar system. After regaining enough strength to explore, he enters an adjacent laboratory filled with scientific equipment. By utilizing his innate scientific knowledge to conduct a gravity experiment with a test tube and stopwatch, he calculates the local acceleration of gravity to be 15 m/s2, leading him to the definitive conclusion that he is not on Earth.

The protagonist awakens with amnesia in a high-gravity environment. Using a makeshift pendulum constructed from nylon thread and a tape measure, he conducts experiments to determine that he is on a spacecraft rather than in a terrestrial centrifuge. As he recovers fragmented memories, he recalls a global crisis known as the 'Petrova problem,' characterized by an exponential decrease in the sun's luminosity. He remembers a dinner with Marissa, a DOE employee, and a NASA broadcast featuring Dr. Browne discussing Project ArcLight, an international mission to Venus to investigate the Petrova line. The broadcast reveals that the ArcLight probe discovered shifting, deforming particles resembling microbes. The protagonist eventually realizes he was part of a crew in suspended animation and is the sole survivor. Amidst these revelations, he recovers personal details about his past, remembering that he lived in a small apartment in San Francisco and worked as a schoolteacher, all while the ship's computer alerts him to an 'angular anomaly.'

Ryland Grace, a former molecular biologist and current junior high science teacher, is recruited by Eva Stratt of the international Petrova Taskforce. Stratt reveals that the sun is dying due to energy-consuming life-forms and leverages Grace's research on non-water-based life to enlist his help. After being forcibly taken to a secret lab, Grace identifies the organisms as 'Astrophage'—single-celled entities from Venus that consume stellar energy and propel themselves using infrared light at the Petrova frequency. In the present, Grace awakens aboard a spaceship called the Hail Mary. After analyzing the ship's velocity, acceleration, and a real-time image of a nearby star, he calculates that the star's sunspots are rotating far too quickly to be the sun, leading him to the shocking realization that he is in a different solar system.

The narrator, identified as Grace, awakens in a spacecraft in another solar system to find himself the sole survivor of his crew. After recovering from initial panic, he methodically analyzes the ship's systems and recalls his previous research on Astrophage, a 'warm-blooded' alien microbe composed mostly of water that maintains a constant temperature of 96.415°C. Grace retrieves uniforms from storage and performs the grim task of dressing and jettisoning the bodies of his deceased crewmates, Commander Yáo Li-Jie and Olesya Ilyukhina, into space. Through memories of his time as a science teacher and his strained professional relationship with the administrator Stratt, Grace recalls the catastrophic threat Astrophage poses to Earth: as a 'space algae' absorbing the sun's energy, it threatens to trigger a mass extinction event by dropping Earth's temperature. Upon analyzing the ship's remaining fuel and acceleration, Grace realizes he is on a one-way suicide mission, with the only means of transmitting his findings back to Earth being four unmanned probes named after the Beatles.

Dr. Ryland Grace conducts a series of experiments to understand the life cycle of Astrophage, discovering that they are attracted to the spectral signature of carbon dioxide and migrate from the sun to Venus to obtain the carbon and oxygen necessary for reproduction. After successfully inducing the cells to divide, Grace is rapidly transported by military forces to a Chinese aircraft carrier. There, he joins an international team led by Stratt, who reveals that the sun's dimming is part of a larger interstellar infection affecting multiple stars in the local cluster. The team identifies Tau Ceti as a critical anomaly because it remains unaffected despite being surrounded by infected stars. Dr. Dimitri Komorov explains that Astrophage can convert energy into mass and vice versa, providing a theoretical basis for an interstellar engine. Consequently, Grace is tasked with designing a large-scale Astrophage-breeding facility, which must be located in the ocean to mitigate the risk of catastrophic explosions.

The protagonist awakens in the Tau Ceti system aboard the Hail Mary, struggling with memory loss and the devastating realization that he is the sole survivor of his crew. Through a series of flashbacks, he recalls meetings with Stratt regarding the mission's extreme psychological risks and the necessity of selecting crew members based on a rare genetic 'coma resistance' required for the long journey. After the ship's engines shut off and he recovers from a panic attack induced by the transition to zero gravity, the protagonist utilizes the ship's scientific instrumentation to investigate Tau Ceti. He confirms the existence of a Petrova line but notices it is being obstructed. Upon switching to visible light, he discovers a fabricated, triangular alien object positioned near his ship, leading to the profound realization that humanity is not alone in the universe.

The narrator discovers an alien spacecraft, which he names 'Blip-A', positioned near the Hail Mary. After establishing a basic communication pattern using engine flashes in the Petrova frequency, the aliens use a hull-mounted robot to launch a cylindrical object toward the narrator's ship. Despite his amnesia and the risks involved, the narrator dons an Orlan-MKS2 EVA suit and exits the airlock to retrieve the object, reflecting on his lost crewmates and his apparent specialized training in EVA procedures. Upon bringing the cylinder inside, he discovers it smells of ammonia and is unexpectedly hot, suggesting an internal heat source. He places the object in the airlock to cool and prepares to analyze it in the ship's lab, while reflecting on the lab's design and his own memory loss.

Ryland Grace recalls a meeting in Geneva where Dr. Lokken convinced Stratt to incorporate a centrifuge into the Hail Mary's design to ensure the reliability of lab equipment in simulated gravity. In the present, Grace activates the centrifuge sequence, creating 1g of gravity, and begins analyzing an alien artifact. Using a spectrometer, he discovers the artifact is made of a solid, reactive xenon-based material. Upon opening the cylinder, Grace finds a star map indicating a Petrova line connecting Tau Ceti to 40 Eridani, leading him to conclude the aliens (whom he names Eridians) are also facing the Astrophage crisis. Grace modifies the map to include Earth's location and returns it to the alien ship, Blip-A. In response, the aliens send a second cylinder containing a model that proposes a physical connection between the two ships for a meeting.

The narrator initiates a communication process with the Eridians by providing a sample of the Hail Mary's hull to assist them in constructing a connecting tunnel. While awaiting their response, the narrator reflects on Eridian biology, concluding that the 'Goldilocks zone' theory is incorrect because the Eridians likely thrive in much higher temperatures. He also recalls a flashback to the development of the spin drive by Dimitri and Stratt, detailing the drive's design using multiple small engines and its immense power. Eventually, the Eridian ship, Blip-A, approaches and attaches a xenonite tunnel to the hull using an adhesive. After carefully managing the pressurization of the tunnel and noting a strong smell of ammonia, the narrator takes a 'leap of faith,' exiting his EVA suit to enter the tunnel. He discovers a hot, multicolored hexagonal divider wall separating him from the Eridians, who signal their presence by knocking.

Ryland Grace establishes first contact with an alien being he names Rocky. After initial communication through tapping and visual models, Grace discovers Rocky's physical appearance—a pentagonally symmetrical, rock-skinned creature with five hands—and realizes they communicate via musical chords. Through the exchange of molecular models, Grace deduces that Rocky's atmosphere consists of ammonia and is approximately twenty-nine times the pressure of Earth's atmosphere. To manage his extreme fatigue, Grace uses an analog clock to negotiate a two-hour nap. In response, Rocky shares an Eridian clock, which allows Grace to deduce that Eridians use a base-six numbering system and read from left to right. By timing the Eridian clock's rotors with a stopwatch, Grace calculates that one Eridian second is approximately 2.366 Earth seconds, establishing a fundamental unit of time to facilitate future scientific communication.

The narrator discovers that Rocky, an Eridian, perceives the environment through passive sonar rather than light, after observing that Rocky cannot see ink markings on a tape measure but can perceive gestures behind an aluminum panel. This realization leads the narrator to use waveform analysis software and Fourier transforms to begin learning the Eridian language. Interspersed with these discoveries is a flashback to Eva Stratt's ruthless acquisition of all human digital knowledge for Project Hail Mary, where she used international immunity and military force to bypass intellectual property laws. In the present, the narrator speculates on Rocky's role as a potential captain and confirms Rocky's unique identity based on physical carapace features. After attempting to communicate via improvised tools like Popsicle sticks, the narrator sets up a makeshift camera monitor in the tunnel and retires to sleep.

The narrator and Rocky work to establish a shared language using waveform analysis software and a spreadsheet to translate Eridian musical chords into English. After developing a basic vocabulary and grammar, they confirm that both their home stars, Sol and Eridani, are plagued by Astrophage. The narrator discovers that Eridians possess photographic memory and a high aptitude for mathematics, contrasting this with the 'mess' of human evolution. To establish a shared understanding of mass, the narrator uses a makeshift centrifuge and water displacement to measure a metal ball provided by Rocky, eventually determining it is iron with a mass of approximately 328 grams. As they bond, Rocky explains Eridian sleep patterns and requests that the narrator observe him while he sleeps. The chapter concludes with a poignant revelation: Rocky was the sole survivor of a crew of twenty-three, and the narrator is the sole survivor of a crew of three, creating a deep emotional bond between the two survivors.

In this chapter, Stratt and Dr. Grace visit Dr. Robert Redell, a convicted felon in New Zealand's maximum-security Auckland Prison. Redell proposes the 'blackpanel' concept—paving a vast portion of the Sahara Desert with specialized panels to mass-produce Astrophage at a scale of a thousand kilograms per day. Stratt, prioritizing pragmatism over morality, agrees to recruit Redell despite his history of embezzlement and culpable homicide. In the present, Dr. Grace and Rocky discuss their shared mission to save their home systems. Their conversation reveals a significant scientific gap: Eridians are unaware of the concept of radiation, which explains why Rocky's crewmates died without apparent cause. Additionally, a flashback depicts Dr. Grace and a Norwegian colleague reviewing a CERN paper. They deduce that Astrophage stores energy as neutrinos, which are Majorana particles that annihilate into photons of the Petrova wavelength. This discovery leads to a proposal to use a one-millimeter layer of Astrophage slurry as radiation shielding for the Hail Mary hull, leveraging the organism's 'super cross-sectionality' to block solar particles and Galactic cosmic rays.

Chapter 14 alternates between a desperate flashback on Earth and the present-day scientific exchange between the narrator and Rocky. On Earth, Stratt recruits climatologist Dr. François Leclerc, who predicts that half of humanity will perish within nineteen years due to Astrophage-induced solar energy reduction and crop failure. To extend human survival to twenty-seven years—the window needed for the Hail Mary mission to succeed—Stratt orders a massive nuclear strike on Western Antarctica to release trapped methane and create a temporary greenhouse effect. Despite his environmentalist beliefs, Leclerc executes the plan, and both he and Stratt accept the likelihood of future imprisonment as a necessary sacrifice. In the present, the narrator explains radiation to Rocky, discovering that Eridians are extremely susceptible to it because their homeworld, Erid, possesses a massive magnetic field and thick atmosphere. Rocky survived the radiation that killed his crew only because he was shielded by Astrophage fuel in his workshop. The two scientists discuss their vastly different biologies—including Eridians' steam-powered physiology and use of liquid mercury as blood—and hypothesize about panspermia. The chapter concludes with Rocky building a xenonite geodesic sphere and life-support system, cooled by Astrophage, to safely visit the narrator's ship.

Dr. Grace and Rocky collaborate to move Rocky and his equipment from the Blip-A to Grace's ship, utilizing a new tunnel with a larger airlock and magnetic strips. After a tour of the ship's facilities, Rocky proposes detaching the tunnel so the ship can rotate to generate gravity. During their interactions, Rocky reveals he has been alone in the system for forty-six Earth years and is 291 Earth years old, noting that the average Eridian lifespan is 689 Earth years. The chapter also features a flashback to Grace's time on Earth, where he worked with Dr. Lamai and Stratt on coma-resistance technology, highlighting the genetic markers required for the Hail Mary mission and the necessity of non-neural network systems for automated care stations.

Ryland Grace and Rocky establish a shared living arrangement on the Hail Mary, utilizing xenonite to separate their incompatible environments. In a significant act of altruism, Rocky offers Grace two million kilograms of Astrophage, providing the fuel necessary for Grace to return to Earth. The narrative shifts to a flashback regarding the selection of the Hail Mary's crew, where Eva Stratt's utilitarian and controversial criteria are revealed, introducing the prime crew members Yáo, Ilyukhina, and Martin DuBois, as well as backup specialist Annie Shapiro. In the present, Grace and Rocky plot a course for Tau Ceti e to study Astrophage, a planet Rocky names after his mate. Additionally, Grace's scientific curiosity leads him to observe Rocky's biological processes, discovering that Eridians are hermaphrodites with a monostome digestive system and a biologically enforced sleep state following meals.

Ryland Grace and Rocky arrive at Planet Adrian, a rocky world with a thick, methane-rich atmosphere. While Grace manages the ship's orbital-insertion burn and analyzes the atmosphere via spectrometry, Rocky develops a device that converts light wavelengths into tactile textures to perceive human-visible light. The narrative intercuts with Grace's memories of training at NASA's Neutral Buoyancy Lab (NBL), where he used Russian Orlan EVA suits and interacted with colleagues Martin DuBois and Annie Shapiro. Upon arriving at Adrian, Grace performs an EVA to retrieve samples using the External Collection Unit. Analysis of these samples reveals a diverse array of translucent cells and organisms alongside Astrophage. Grace and Rocky discover that the population of Astrophage moving toward and away from the planet is equal, leading Rocky to conclude that life on Adrian preys on Astrophage. This discovery suggests that Adrian is the homeworld of Astrophage and that a biological predator could be the key to saving the stars.

Chapter 18 alternates between the present mission and flashbacks to the preparation of Project Hail Mary. In the present, Grace and Rocky attempt to sample a predator from Adrian's atmosphere. After a failed attempt using a glass bulb, Grace identifies the Astrophage breeding altitude at 91.2 kilometers and devises a plan to use a 10-kilometer xenonite chain to 'fish' for the predator while thrusting at a 30-degree angle to avoid vaporization. During this process, Rocky reveals that Eridians produced Astrophage in their hot oceans and shares the details of his journey to Tau Ceti. Grace realizes that Eridians are unaware of relativistic physics, which explains Rocky's confusion regarding his travel time and fuel surplus. Flashbacks depict the crew watching the successful launch of the ship's cockpit, lab, and dormitory modules from an aircraft carrier. Additionally, Grace interacts with Steve Hatch, a Canadian researcher who developed 'beetles'—small, unmanned probes designed to return data from the mission to Earth. While Hatch views Astrophage as a potential gift for a renewable energy future, Grace remains focused on the impending mass extinction and starvation facing humanity.

The narrator and Rocky collaborate to collect an atmospheric sample from the planet Adrian to identify predators of Astrophage. This process involves two weeks of tedious labor to manufacture ten kilometers of xenonite chain, which is then used to lower a sampler probe into the breeding zone. The narrator performs a high-risk EVA in 1.4 g gravity to retrieve the probe, but the mission is interrupted by catastrophic ship movements. Upon returning to the ship, the narrator discovers a hull breach caused by infrared light reflecting off Adrian's atmosphere. This breach exposes the Astrophage fuel, which begins migrating toward the planet, creating uncontrolled thrust. To stop this, the narrator jettisons two fuel bays, which triggers a violent spin. The narrator is pinned by his sheared-off pilot seat and suffers from mechanical suffocation. Rocky risks his own life to enter the narrator's partition and rescue him, but the effort leaves Rocky unconscious and severely overheated.

Following a catastrophic event that left the ship tumbling and the crew compartment upside down, Ryland Grace manages to reduce the centrifugal force by extending the ship's cables. He endures severe chemical burns from ammonia to move an unconscious Rocky into the airlock and return him to his native environment. After recovering from his injuries and stabilizing a sample from Adrian, Grace focuses on saving Rocky, whose carapace radiator was literally on fire due to oxygen passing over hot metal pipes. Grace constructs a specialized device—a steel box equipped with a high-powered air pump, drill, and camera—to clear soot and debris from Rocky's vents. Despite facing extreme physical pain, exhaustion, and technical failures like a melted camera, Grace successfully clears the vents. Throughout the process, he also manages ship maintenance, such as repairing a micro-breach in the bulkhead between the storage bay and Fuel Bay 4, while struggling with the ship's restrictive automated painkiller system.

The narrator manages the grim task of coordinating suicide methods for the Hail Mary crew—Yáo, DuBois, and Ilyukhina—while simultaneously recovering from burns and collaborating with Rocky. Their discussions touch upon evolutionary biology, intelligence, and the universal nature of hearing frequencies. As an administrator in Kazakhstan, the narrator oversees the final preparations for the $10 trillion mission, but the process is interrupted by a catastrophic explosion at the Baikonur research center. The blast vaporizes metal and kills science specialists DuBois and Shapiro. Despite the tragedy, Stratt insists on immediate pragmatism, ordering the narrator to find replacements from a coma-resistant list. Amidst this crisis, the narrator and Rocky discover a microbe from Tau Ceti that preys on Astrophage, which the narrator names 'Taumoeba.' They begin testing the organism's viability in simulated atmospheres of Venus and Threeworld to determine if it can stop the Astrophage infestation, ending the chapter as the lights go out.

The Hail Mary suffers a total power failure after Taumoeba contaminate the fuel supply, consuming the Astrophage and leaving behind methane and waste. After the narrator and Rocky discover the contamination, Rocky restores basic electrical power by sterilizing a generator and using his own limited supply of Astrophage. The narrator realizes that the 'beetles'—small probe ships—contain sealed, uncontaminated fuel. This leads to a series of dangerous EVAs where the narrator, utilizing multiple tethers for safety, retrieves the four beetles (John, Paul, George, and Ringo). Rocky modifies three of the beetles to serve as makeshift engines, which are mounted to the hull using xenonite glue. The narrator then endures extreme g-forces, eventually blacking out at 6 g's, to pull the ship's halves together and stabilize its rotation. Once back in zero gravity, the narrator begins calculating the trajectory to return to Rocky's ship.

Chapter 23 alternates between the present and a flashback to Dr. Grace's recruitment. In the present, Grace and Rocky use modified 'beetle' probes with xenonite struts to accelerate toward Blip-A at 1.5 g's. However, Grace is devastated to discover that his Taumoeba experiments failed to survive simulated Venus and Threeworld environments. The flashback reveals that a catastrophic measurement error at a research center—where a milligram of Astrophage was used instead of a nanogram—killed the primary and backup science specialists. Because Grace is coma-resistant and possesses the necessary training, Stratt attempts to recruit him. When Grace refuses, citing his role as a teacher and his fear of death, Stratt labels him a coward. She ultimately resorts to forced recruitment, ordering Meknikov to restrain him. Stratt reveals her plan to sedate Grace, lie to Commander Yáo and Specialist Ilyukhina about his condition, and use a French DGSE drug to induce retrograde amnesia to ensure his cooperation upon waking at Tau Ceti.

The narrator recovers suppressed memories of his panic and reluctance to join the mission, leading to a period of self-loathing and the realization that he was forced into the role. Despite this emotional turmoil, he and Rocky collaborate on a scientific solution to the Taumoeba threat. After discovering that nitrogen is lethal to Taumoeba, the narrator implements a selective breeding program using ten tanks with incremental nitrogen increases to develop nitrogen-resistant strains. To facilitate this lab work, the pair risks a dangerous spin-up of the ship to create 1 g of gravity. Parallel to these experiments, the narrator and Rocky coordinate a rendezvous with Rocky's ship, the Blip-A. Using the Petrovascope and precise navigational adjustments to yaw and pitch, the narrator locates the distant ship—which is too far for radar detection—and the two agree to accelerate toward it at 15 meters per second per second.

Grace and Rocky achieve a critical scientific breakthrough by breeding Taumoeba-82.5, a strain capable of surviving in both Venusian and Threeworld atmospheres, ensuring the survival of both their home planets. The process is described as a slow, steady progression rather than a single moment of discovery. Parallel to this, Grace faces a logistical crisis when he discovers fuel bays contaminated with Taumoeba; after jettisoning one, he realizes he lacks sufficient food for the return trip. Rocky resolves this by fabricating replacement fuel bays from a 'metal stew' alloy salvaged from the Blip-A. After installing the new bays and fueling the Hail Mary with 2.2 million kilograms of Astrophage, the two celebrate with vodka and special clothing. The chapter concludes with an emotional farewell as Grace and Rocky exchange gifts, including a laptop of human technology, and detach their ships to return to their respective worlds.

The chapter alternates between a flashback to Ryland Grace's final moments on Earth and his current journey back from Tau Ceti. In the flashback, Eva Stratt visits Grace in his cell at the Baikonur facility. She reveals her background as a history major to justify her ruthless pragmatism, arguing that Astrophage is an apocalyptic threat that will lead to global war, famine, and societal collapse over food resources. In the present, Grace is eighteen days into his return trip. He manages his boredom by cataloging the lab, tending to Taumoeba farms, and performing a daily ritual of using the Petrovascope to watch Rocky's ship (Blip-A) recede. He prepares the 'beetle' probes by refueling them and attaching Eridian-steel mini-farms containing Taumoeba to ensure Earth receives the cure. The chapter ends on a cliffhanger when Grace discovers the smell of rotting Astrophage in his main storage container, indicating that Taumoeba have escaped and are consuming his fuel.

The protagonist discovers a Taumoeba infestation in the BOCOA, prompting an immediate emergency response to prevent the organisms from reaching the ship's fuel bays. After identifying life support as the likely transmission vector, he disables the heating system and shuts down the spin-drive engines to prevent the spread of Taumoeba through fuel lines. To eradicate the loose organisms, he utilizes a nitrogen canister to flush the ship's atmosphere, venting the oxygen into space and replacing it with a lethal concentration of nitrogen. Following a three-hour sterilization period, he restores the air and implements a rigorous isolation protocol for all remaining Taumoeba sources, including the breeder farms and the beetles' mini-farms, placing them in overpressurized nitrogen bins to detect any further leaks.

Following a Taumoeba escape into the fuel system, the narrator spends several days conducting a systematic investigation to identify the source of the leak. After ruling out the mini-farms and confirming that the breeder farms are leaking despite being made of xenonite—a material previously thought to be impermeable—the narrator hypothesizes that the microbes are navigating the molecular structure of the material. Through a series of controlled experiments using 'Astrophage sandwiches' made of xenonite and plastic, the narrator discovers that while natural Taumoeba cannot penetrate xenonite, the engineered strain Taumoeba-82.5 can. This unintended evolutionary trait developed because the microbes evolved to hide within the xenonite walls to escape the nitrogen used in the breeder tanks. While the narrator initially believes the problem is easily solvable by switching to metal containers, he suddenly realizes the catastrophic implication: Rocky's ship is constructed almost entirely of xenonite, meaning Rocky's fuel supply is currently vulnerable to the same leak.

The narrator discovers that Rocky's ship, the Blip-A, has gone silent, concluding that Taumoeba consumed its Astrophage fuel. Faced with a choice between returning to Earth as a hero or saving Rocky and the Eridian species, the narrator chooses the latter, knowing he lacks the food to make a return trip. After launching four beetles containing Taumoeba and data toward Earth, he employs an ingenious radar method using the ship's spin drives and Petrovascope to locate the derelict Blip-A. Upon finding the ship on an escape vector from Tau Ceti, the narrator performs a precarious EVA to board the vessel. He finds Rocky alive but injured by a Taumoeba-82.5 infestation that penetrated the xenonite hull. While the narrator resigns himself to dying after reaching Erid, Rocky suggests that Taumoeba might be a viable food source for humans, offering a glimmer of hope for the narrator's survival.

Set sixteen years after the events of the main narrative, Grace Miller now lives on the planet Erid in a specialized dome environment. He has aged significantly, suffering from bone degeneration and arthritis due to Erid's high gravity, and relies on a cane. The Eridians have provided him with a high standard of care, including synthesized vitamins and lab-grown human muscle tissue for food. Grace maintains a close friendship with Rocky and has become a teacher for Eridian children, using a specialized organ to communicate. The emotional climax of the chapter occurs when Rocky informs Grace that Sol has returned to full luminance, confirming that the Astrophage threat has been neutralized and Earth has been saved. While Grace contemplates returning home via the Hail Mary, he decides to stay on Erid for the time being, finding meaning in his current life and his role as an educator.