The Martian

Six sols into Ares 3's planned thirty-one-sol surface stay, a storm with 175 kph winds threatens the Mars ascent vehicle (MAV), exceeding the mission's 150 kph design limit. NASA orders an abort. While the crew moves from the Hab to the MAV, the main communications dish tears loose and an antenna pierces Mark Watney's flight suit and side. Johanssen reaches toward him, but he is blown away. Damage to his biomonitor and a nearly complete suit depressurization make his crewmates believe he is dead, and they depart.

Watney awakens after the storm, partly buried in sand. His fall bent the antenna against the suit breach, and dried blood helped seal the leak. His suit maintained pressure using nitrogen and eventually pure oxygen when the carbon-dioxide filters and nitrogen reserves were exhausted. At risk from excessive oxygen, he removes the antenna, applies a breach patch, and returns to the intact Hab. He closes his wound with nine stitches and takes antibiotics.

The MAV is gone, and the primary communications dish and receiving antennas are destroyed. The Hab's other radios rely on the now-absent MAV; Watney expects Hermes to leave Mars orbit within twenty-four hours of the abort. He explains the mission's prepositioned supplies, the Hermes ion drive, and the MAV's lengthy fuel-production process. Stranded without a working link to Earth or his crew, he has a Hab designed for a thirty-one-sol mission. Failure of the oxygenator, water reclaimer, or Hab pressure would kill him, and even if those systems endure, he will run out of food.

On Sol 7, Watney inventories what the storm left behind. Food intended to feed six people for fifty more sols gives him 300 days at full rations, or about 400 if he eats three-quarter portions. The Hab, its oxygenator and water reclaimer, six EVA suits, two rovers, and a cleaned solar array remain usable. The oxygenator has a temporary carbon-dioxide-filter backup, but the water reclaimer does not. The MDV is damaged, the MAV's ascent stage and main radio dish are gone, and his expendable EVA filters provide approximately 1,500 hours outdoors.

Watney is both a botanist and a mechanical engineer. He searches unsuccessfully for the dish and considers contacting Earth or the returning Hermes. Ares 4 is expected to land in Schiaparelli crater, about 3,200 kilometers away, on Sol 1412, but he cannot currently reach it or live that long. He instead tries to grow food. He brings Martian soil into the Hab, combines it with a small supply of living Earth soil, and uses preserved crew waste and his own waste to establish bacteria and nutrients. Edible potatoes and other food supplies might serve as seed crops.

Water restricts his intended 92-square-meter, ten-centimeter-deep soil bed: it would require 368 liters, while he can spare only 250 of the Hab's 300-liter reserve. He therefore plans about 62.5 square meters, waters an initial five-square-meter patch, and begins multiplying the living soil. Thinking of his family's grief over his presumed death also weighs on him. His potato calculation is discouraging: an estimated 150 kilograms would provide about 115,500 calories, enough for roughly seventy-six days, with subsequent cultivation adding about fifteen more. Farming would push starvation from approximately Sol 400 to Sol 490, still far short of Sol 1412. He ends the chapter without a way to close that food deficit.

By Sol 25, Watney calculates that he needs approximately 1,425 Earth days of food until Ares 4 and about 1,100 additional calories per day from farming. His current 62-square-meter cultivation plan would produce only about 288 calories daily. He identifies a potential 126 square meters by using the Hab floor, unused bunks, two laboratory tables, and both rovers' emergency pop-tents. Intensive tending and replanting might raise potato yield by 50 percent, giving an estimated 850 calories daily, still short of his target. Expanding the growing area also requires about 250 additional liters of water beyond what he can spare.

Watney transfers more dry soil into the Hab, prepares bunks and tables, and deploys the pop-tents as additional planting spaces. Their airlocks cannot mate directly with the larger Hab airlocks, so he uses compatible air-feed connections to replace air lost on entry. He cuts twelve refrigerated Thanksgiving potatoes into forty-eight seed pieces and plants them in an already prepared corner. Warmer conditions and controlled lighting may produce sproutable tubers in about forty days, but this is a seed crop, not a completed food harvest. He distracts himself with television shows from Commander Lewis's data-stick.

To supply water for the remaining soil, Watney proposes generating oxygen from carbon dioxide collected by the abandoned MAV fuel plant and processed through the Hab oxygenator. The plant could collect enough carbon dioxide over ten sols for the oxygen needed to make 250 liters of water. He also finds 292 liters of hydrazine in the damaged MDV and proposes decomposing it over an engine catalyst to obtain hydrogen. The hot reaction could explode in an oxygen atmosphere, and he has not solved how to control the decomposition or safely collect the hydrogen. The chapter ends with that problem unresolved, while he turns back to television.

On Sol 32, Watney works out how to manufacture water without enough high-pressure tanks to store the required gases. His larger goal is 600 liters of water, but collecting oxygen from Martian carbon dioxide through the abandoned MAV fuel plant and the Hab oxygenator will take time. He connects the fuel plant to power and devises a dangerous continuous process: drip hydrazine from the damaged descent vehicle over an iridium catalyst to release hydrogen, direct it through a makeshift chimney, and ignite it inside the Hab. The water reclaimer should collect the resulting moisture.

Watney extracts the MDV's hydrazine tanks and reaction chamber, assembles the apparatus from hoses, sample bags, duct tape, and a space-suit air line, and uses splinters from Martinez's wooden cross to maintain a pilot flame. Wearing improvised protection against toxic hydrazine, he controls the flow and watches the chamber temperature. The procedure apparently produces about 50 liters of water, leaving the Hab hot and humid. He stores recovered water in a spare space suit and, encouraged, continues producing water over several days.

An accounting discrepancy then undermines his confidence. He estimates having made 130 liters but has recovered only 70 liters in containers, with additional moisture in the soil and air. Oxygen has been accumulating in a reserve tank, suggesting he has burned less hydrogen than assumed. Watney concludes that unburned hydrogen is building up in the Hab. An atmospheric sample analyzed in a rover reads 64 percent hydrogen, 22 percent nitrogen, and 9 percent oxygen. He retreats to Rover 2. Its carbon-dioxide filters give him only a day or two to decide what to do, and the chapter ends before he has a solution.

Still sheltering in Rover 2, Watney reasons that he can burn off the hydrogen safely if he first removes nearly all oxygen from the Hab. He plans to cool the habitat to 1°C to slow the soil bacteria and preserve them at about 1 percent oxygen, while moving the unsprouted potato plants into a heated rover. The atmospheric regulator refuses to lower oxygen below 15 percent because of its safety controls. Watney instead blocks eight of its nine sampling intakes and supplies the remaining sensor with pure oxygen, causing the regulator to withdraw oxygen from the Hab. Wearing a medical breathing mask, he monitors the real oxygen level with an EVA suit sensor and switches off the regulator at 1 percent.

Watney uses a spark and small, controlled oxygen releases to burn the hydrogen. The process works until an explosion throws him across the Hab and tears away his breathing mask, leaving him briefly breathing an oxygen-poor atmosphere. He reaches the oxygen supply of Lewis's spare suit, turns the regulator back on, and survives. After sleeping in the rover, he returns to inspect the Hab. Its pressure boundary, oxygenator, regulator, water reclaimer, storage tanks, and other essential systems still function. Microscope samples show the soil bacteria survived.

Watney proposes, rather than proves, that his exhaled breath gradually reintroduced oxygen from the loosely fitting mask until the remaining hydrogen ignited. The explosion did not rupture the Hab. He accounts for the missing 60 liters of water as 50 liters captured by the water reclaimer and 10 absorbed by dry soil. He calls Lewis's water-filled suit the Cistern and returns the sprouting potato seedlings to the Hab. Only 130 of the intended 600 liters have been produced, leaving 470 liters to make. He plans continued hydrazine processing with more frequent hydrogen cleanings, and ends by watching television.

Two months after Watney's presumed death, Venkat Kapoor requests new satellite images of the Ares 3 landing site, hoping the surviving supplies could support a proposed Ares 6 mission. NASA administrator Teddy Sanders initially refuses because images might show Watney's body and renew damaging publicity. Once the images are authorized, satellite technician Mindy Park notices an intact Hab, clean solar panels, and two deployed pop-tents absent from the evacuation logs. She also cannot find a body. Venkat examines other evidence: Rover 2 has moved since its last recorded charging position, the damaged Mars descent vehicle (MDV) has been dismantled, and the remaining MAV fuel plant has been removed. He concludes that Watney is almost certainly alive.

Teddy, Venkat, and media director Annie Montrose decide not to tell the Ares 3 crew, who still have ten months of return travel aboard Hermes, for fear of endangering their concentration. Teddy goes to Chicago to tell Watney's parents before the public announcement. NASA then announces the discovery, drawing global media attention. Venkat's specialists determine that Watney's Hab dish was the only independent surface link: the other three communications systems were aboard the departing MAV, and an orbiting satellite cannot transmit a usable signal to him without the dish. NASA has no means of contacting him yet.

Nine days after the announcement, Teddy publicly commits NASA to the rescue effort. NASA redirects satellite observation time and asks the SETI network to look for weak signals, without success. Venkat relays a preliminary JPL plan for the Ares 4 crew to land at the Ares 3 site in a stripped-down MDV and make a hazardous lateral flight to the Ares 4 MAV. Teddy rejects the danger to another crew, while Venkat acknowledges there is still no way to keep Watney alive until Ares 4 arrives. Teddy wonders what Watney is thinking; the chapter's final line abruptly turns to Watney's complaint about Aquaman controlling whales.

With water production completed and his potatoes growing, Watney starts planning for a possible journey from Acidalia Planitia to the Ares 4 site, about 3,200 kilometers away. The Ares 4 Mars ascent vehicle (MAV) has already landed there, and he saw Martinez pilot its remote descent. Watney calculates that Rover 2 needs more energy and equipment than a normal short-range rover. He transfers Rover 1's 9,000-watt-hour battery to a canvas-and-resin harness on Rover 2, bringing total capacity to 18,000 watt-hours, with manual cable changes during EVAs. He also mounts fourteen Hab solar panels, covering 28 square meters, on the roof. His theoretical travel range is about 90 kilometers per charge, less over rough ground, followed by hours of solar recharging.

Watney digs up his first small potato seed crop after thirty-nine sols and replants cut tubers to expand production. He names his rover experiments Sirius. Sirius 1 fails after an hour because he has disabled the electric heater to conserve energy and becomes too cold to continue. For Sirius 2, he retrieves the radioisotope thermoelectric generator (RTG) that Lewis buried four kilometers south of the Hab. The sealed unit produces about 1,500 watts of heat, compared with only 100 watts of electricity. It overheats the rover to 37°C in ten minutes, so Watney removes some insulation to balance heat loss. Sirius 2 also verifies that the battery sling and solar panels survive travel.

Sirius 3 covers 81 kilometers in three hours and twenty-seven minutes on two batteries and requires twelve hours of charging, assisted by the RTG's electrical output. Watney reserves power for essential life support while charging and acknowledges the test uses relatively flat terrain. He then prepares a twenty-day Sirius 4 trial. An additional Hab oxygen tank would extend his oxygen supply to about forty-nine days, and he has 2,089 hours of carbon-dioxide filters available. Before leaving he plans to water the potatoes heavily, supply carbon dioxide from the MAV fuel plant, and shut down the Hab's atmospheric regulator and oxygenator. The chapter ends with Sirius 4 planned for the following day, not yet begun.

NASA's regular satellite coverage reveals Watney's Rover 2 battery and solar-panel modifications and his short test journeys. On CNN, Venkat Kapoor worries that Watney may try to reach the Ares 4 MAV, 3,200 kilometers away, without enough life support. JPL is still considering an alternative in which a modified descent vehicle can land at the Ares 3 site and then travel toward Ares 4. At a NASA leadership meeting, JPL director Bruce Ng describes a revised approach involving detachable heat shielding and outer hull. Teddy Sanders orders satellite technician Mindy Park to reduce surveillance gaps from seventeen to four minutes. Ares 3 flight director Mitch Henderson argues the returning crew should be told Watney is alive, but Teddy refuses until NASA has a credible rescue plan.

Keeping Watney alive until a later rescue requires a food presupply. NASA estimates a nine-month Mars transit at the current planetary positions, leaving only about three months to build a probe that normally takes six. Teddy agrees to divert the only suitable Delta IX booster from the EagleEye 3 Saturn mission if JPL can prepare the payload. JPL also considers how to alert Watney after the probe lands: a powerful radio broadcast on rover frequencies and conspicuous green ribbons advising him to turn on his receiver. These remain proposals, not equipment already launched. In media interviews, flight psychologist Irene Shields discusses Watney's resourcefulness but cautiously raises the possibility that his preparations could reflect a wish to contact people before dying, not necessarily a viable escape plan.

Mindy reports that Watney has gone seventy-six kilometers from the Hab, then 156 kilometers, traveling south-southwest instead of toward Ares 4 to the southeast. Venkat plots his positions on a Mars map and finds the projected route passes through the Pathfinder landing site. He infers Watney is trying to recover Pathfinder and its Sojourner rover, potentially restoring radio contact if the old hardware can be restarted. Venkat calls Bruce to assemble former Pathfinder staff at JPL. No communications link has yet been established.

During Sirius 4, Watney travels to the old Pathfinder site in Ares Vallis, managing Rover 2's oxygen and carbon dioxide, stored waste, RTG heating, batteries, and roof-mounted solar panels. At each day's stop he must lay out the panels for roughly twelve hours of charging. Beyond the forty-kilometer range of the Hab's navigation beacon, he steers by the Martian moon Phobos and later by visible features he names Lewis Valley and the Lighthouse crater, then Hamelin crater. As he approaches Pathfinder, the terrain grows rocky. He reflects on his isolation and his need to talk to another human, the reason he wants to recover a communications system.

On Sol 82, Watney finds the Pathfinder lander near the Twin Peaks hills and retrieves its smaller Sojourner rover. The lander, not Sojourner, contains the equipment capable of communicating directly with Earth. He pries away the outer panels, tows them aside with Rover 2, and digs out the central lander assembly from sand-filled descent balloons. The approximately 200-kilogram assembly is too heavy to lift safely in an EVA suit. He also considers a future two-way message system: he could display writing to the lander's camera, while NASA might control Sojourner's six wheels marked with letters. This remains hypothetical because Pathfinder is not yet operating.

On Sol 83, Watney builds a nearly four-meter-long ramp of rocks and sand at a thirty-degree grade, drags the lander up onto Rover 2's roof, and secures it beside the solar panels, now stacked in one tall pile. To avoid driving over fallen rocks, he takes the ramp apart. With both spacecraft components recovered but unrepaired, he plans to drive back to the Hab the next day.

On the return from Pathfinder, Watney follows his earlier tire tracks through Lewis Valley, then navigates the featureless Acidalia Planitia by Phobos after the tracks disappear. He collects rock and soil samples during EVAs, enjoying work that makes him feel like an astronaut again. He briefly picks up the Hab's navigation beacon, then on the following sol receives a reliable signal placing him 24,718 meters from home. After twenty-two sols in the rover, he reaches the Hab on Sol 94. Watney misses his crewmate Beck, whose medical advice might relieve his aching back, and recalls how closely the crew lived during training.

Back at the Hab he restarts the oxygenator and atmospheric regulator, confirms the potato plants are healthy, deposits his stored waste for recycling, checks systems exposed to the humid air, and returns the portable solar panels to the Hab's electrical grid. He unloads the Pathfinder lander using a salvaged MAV strut as a ramp. Because the Hab's shielding would block its transmission, he leaves the lander outside. He drives the RTG back to the original burial site four kilometers away, then starts working on the spacecraft. Cleaning Sojourner's solar panels and illuminating them produces no visible response; its original nonrechargeable battery is dead.

Watney also finds Pathfinder's dead silver-zinc battery and replaces its 1.5-volt supply using a controller connected to the Hab's power. He places a salvaged Rover 1 heater inside the lander to warm the electronics. When there is initially no movement of the high-gain antenna, he considers whether the thin Martian atmosphere is delaying warming and whether Earth's position has prevented contact. He does not yet know what the lander is doing. The chapter then switches from Watney's logs to Pathfinder's own reboot transcript: its hardware diagnostic finishes, the probe broadcasts its status, waits for telemetry, and finally reports 'SIGNAL ACQUIRED'. This establishes that a signal has been received, but does not yet show a two-way conversation with Watney.

At JPL, Venkat Kapoor and Bruce Ng celebrate the first Pathfinder telemetry received through an improvised control center that has taken engineers twenty days to rebuild. Pathfinder responds to commands after an approximately twenty-two-minute Earth-to-Mars round trip. Watney sees the high-gain antenna point toward Earth and, realizing the probe has contacted NASA, returns to the Hab and cries with relief. Initially Watney communicates by posting handwritten cards in front of the lander's camera, while NASA turns its camera to point to an answer. He then places sixteen hexadecimal cards around the lander so NASA can spell ASCII text with camera rotations, an extremely slow procedure subject to transmission delays.

Watney reports his health, the circumstances of the storm, his cultivated potatoes and intention to reach Ares 4. He emphasizes that his crew was not responsible for abandoning him. Sojourner does not respond, making wheel-based communication unavailable. JPL software engineer Jack Trevor proposes using Pathfinder's separate rover link to transmit software to Rover 2. Because the rover cannot initially accept arbitrary updates, Watney must manually edit its code so it logs incoming beacon bytes. NASA sends a 141-byte modification via the camera alphabet; a regular laptop fails outdoors, so Watney records the digits with a Mars-rated camera and enters the patch in the rover. JPL remotely updates Pathfinder, transmits the larger rover patch, and Watney executes it. Text communication becomes available through the rover's computer, though the interplanetary delay remains.

In the first text exchange, NASA explains plans for a food presupply and a modified Ares 4 descent vehicle. Watney says his existing potatoes may extend food supplies to around Sol 900, but he cannot sustain himself indefinitely. He is angry to learn NASA has withheld his survival from the Ares 3 crew, and NASA asks him to watch his language because the exchange is broadcast live. Separately, Annie Montrose obtains an EVA-suit photograph of Watney making a television-reference gesture. At the chapter's end, flight director Mitch Henderson insists that NASA's agreement to tell the crew once there is a credible rescue plan must now be honored. Teddy Sanders gives permission. The chapter does not yet depict the crew receiving the news.

The chapter returns to Sol 6 and narrates the Ares 3 evacuation from the crew's perspective. Before the storm, Commander Lewis assigns normal sample collection and laboratory duties. Houston's worsening forecast forces the crew into their flight suits, and wind above the 150 kph abort threshold threatens to tip the Mars ascent vehicle (MAV). While the six walk toward it, flying wreckage strikes Watney and carries him west. Johanssen loses sight of him, his suit telemetry goes offline, and Beck reports an incomplete biomonitor packet indicating zero pulse and blood pressure. Lewis sends Martinez ahead to ready the MAV while the others attempt to locate Watney.

With visibility near zero, Lewis orders the other crew members to board but remains outside, searching with rock-drill bits dragged through the sand. The MAV begins tipping toward its 12.3-degree stability limit, then passes thirteen degrees. Martinez uses the nose-cone orbital maneuvering system thrusters to push it upright, preserving the vehicle but reducing the remaining OMS fuel to 22 percent and damaging the nose ports. He and the others urge Lewis to return before the vehicle tips again. Believing Watney dead, she boards and orders launch. Despite turbulence from the open thruster ports, the MAV reaches a Hermes-intercept orbit in eight minutes and fourteen seconds. The crew is silent at Watney's apparent loss.

Four months later aboard the rotating Hermes, the crew opens a routine data transmission. Mitch Henderson's voice message tells them Watney is alive. NASA identified his survival two months earlier but suppressed the information and censored personal communications, intending to wait until a rescue plan and contact were established. Mitch says Watney is healthy, that a modified Ares 4 descent vehicle offers a rescue plan, and that Watney repeatedly says the crew was not at fault. The others react with astonished relief, but Lewis says she personally left Watney behind despite his defense of her decision, then leaves the bridge. The chapter ends with her unresolved guilt.

Now in regular text contact with NASA, Watney receives frequent crop and systems instructions and messages from Earth, particularly a letter from his mother. NASA reports that engineering work on the modified Ares 4 descent vehicle is progressing: the plan is to discard the heat shield, life-support equipment and empty tanks before flying from the Ares 3 site to Schiaparelli. Watney learns Morse code as an emergency one-way backup, using stones visible to satellites if Pathfinder fails. NASA accepts his potato estimates and revises the food-presupply mission to launch during a later transfer window, targeting arrival around Sol 856, before his projected food shortage at Sol 900. Watney and Commander Lewis exchange messages, each insisting the commander made the correct decision on Sol 6.

Between Watney's logs, the narration traces the manufacturing, inspection, delivery and original installation of Hab canvas sheet AL102 at Airlock 1. The sheet passes its tests, but an earlier violent storm causes it to stretch against the comparatively rigid airlock seal-strip. Later, repeated pressure cycling through Watney's frequent use of Airlock 1 gradually weakens already separated carbon fibers. Neither the original inspection nor Watney's later checks reveal the concealed weakness. On Mars, Watney's water reclaimer slows from its normal twenty-liter daily capacity to about ten because minerals from his newly cultivated soil have clogged internal tubing. Despite NASA's objections, he opens the unit, cleans the blockage, and restores normal operation.

A later, relatively moderate fifty-kilometer-per-hour storm prompts Watney to prepare to inspect the solar farm and check Pathfinder. On Sol 119, during a routine airlock depressurization, the weakened AL102 sheet finally tears around Airlock 1. The Hab loses pressure and collapses as its atmosphere propels the detached airlock across the ground with Watney inside. The force breaks his faceplate, injures his head and leaves a small air leak in the detached airlock. He regains awareness looking toward the ruined Hab; the chapter ends before he repairs anything.

Watney survives the sudden Hab rupture inside the detached Airlock 1, now lying about fifty meters from the collapsed habitat. His faceplate is shattered, and air is escaping through a small crack in the airlock. He removes the damaged suit, uses smoke from burned arm hair to locate the tiny leak, and seals it with duct tape. He preserves his only resin patch kit for a more urgent repair. To replace the broken faceplate, he cuts away the left forearm of his EVA suit, applies the suit material over the helmet opening, and seals the shortened sleeve with the remaining resin. The repair holds pressure poorly: at the measured leak rate, his suit can survive only about four minutes outside the airlock.

Watney needs a working suit to return to the Hab and repair its breach, but his spare suits are in the collapsed habitat. Over an exhausting night, he repeatedly throws himself against Airlock 1's inner wall to roll it toward the Hab, stopping about ten meters away. He crosses the surface and finds Martinez's EVA suit pinned under a table and fallen canvas. Unable to remove it with his one useful arm and little air remaining, he takes only Martinez's spare helmet and patch kit. He reaches Rover 2 just before his suit loses pressure. After sleeping, he installs the intact helmet, reseals the suit's shortened arm, refills its gas tanks from the rover, then returns with a lever to recover Martinez's entire suit. The Hab remains unrepaired, and Pathfinder has stopped answering because it was powered from the Hab.

Watney arranges rocks spelling 'A-okay' for NASA's satellites, then inspects the structure. The support poles survived, and he believes he can reseal and reinflate the Hab, but a more serious problem emerges. Depressurization and freezing have killed the potatoes and soil bacteria, including crops in the interconnected pop-tents. The food crop cannot be restarted. Watney estimates that intact ration packs will last to Sol 400 and harvested potatoes might supply another 200 sols, leaving him with food only until about Sol 600. The planned Sol 856 supply delivery is no longer soon enough. The chapter ends with that unresolved deficit.

After repairing and repressurizing the Hab, Watney resumes text contact with NASA and confirms that his farm is dead. He has recovered 1,841 usable potatoes, enough for 184 sols, and expects his combined rations to run out by Sol 584. The water reclaimer initially fails because frozen water burst its hoses; Watney replaces them and restores it. He reports 620 liters of stored water remain after losing nearly 300 liters during decompression. With the former Sol 856 resupply no longer viable, JPL creates a new emergency probe called Iris. On Sol 122, Bruce Ng explains that the shortest Mars transit is 414 days, mounting and inspections take thirteen more, and the factory has just forty-eight days to build a lander. Iris will carry durable food and a radio rather than delicate life-support equipment, with the diverted EagleEye 3 Delta IX booster providing launch capacity.

Iris falls fifteen days behind schedule. NASA administrator Teddy Sanders decides to accelerate booster mounting and omit the usual ten days of inspections despite an estimated 2.5-percent risk that an undetected defect could cause mission failure. NASA cannot safely extend Watney's starvation timeline much further. Meanwhile, astrodynamicist Rich Purnell calculates twenty-five possible 414-day trajectories for uncertain Iris launch dates and notices a possible alternative, but the chapter does not yet explain it. After sixty-three days of round-the-clock work, JPL finishes Iris. Its launch attracts worldwide attention; the flight plan calls for several hours in Earth orbit before a trans-Mars injection.

Shortly after launch, a minor fuel-mixture imbalance causes a lateral vibration. Under extreme acceleration, the contents of protein-food cubes compress and behave as a mobile slurry, shifting Iris's center of mass. When the stages separate and the second stage fires, the resulting impact shears a payload restraint bolt. A second bolt has an unnoticed manufacturing defect that standard inspections could have detected; the remaining restraints fail and Iris strikes its aeroshell. The booster spins, telemetry is lost, and falling debris is reported over the Atlantic. Mission Control initiates failure procedures and Teddy prepares a contingency statement. The chapter ends as Venkat receives a delayed message from Watney asking how the launch went, before NASA answers him.

After the failure of Iris, Guo Ming and Zhu Tao of the China National Space Administration recognize that the booster for China's planned Taiyang Shen solar probe could instead send up to 941 kilograms toward Mars in 419 days. They propose giving NASA the booster in exchange for a Chinese astronaut participating in a future Ares 5 mission. With this option, JPL starts an even faster food-probe project: a twenty-eight-day build for a vehicle with essentially no controlled landing system, intended to crash on Mars at up to 300 meters per second. Its arrival around Sol 624 would be roughly six weeks after Watney's estimated food runs out, requiring ration extensions and a payload that survives impact.

Meanwhile, astrodynamicist Rich Purnell gives Venkat Kapoor an alternative. At a secret NASA meeting called Project Elrond, Venkat explains that Hermes could accelerate instead of continuing its normal deceleration toward Earth, execute an Earth gravity assist, collect a Taiyang Shen-launched resupply package near Earth, then fly past Mars on Sol 549. Watney would have to drive 3,235 kilometers to the Ares 4 Mars ascent vehicle (MAV) at Schiaparelli; the MAV would need major mass reductions to intercept Hermes because the spacecraft would not enter Mars orbit. The flyby would return Hermes to Earth 211 days later, extending the crew's mission by 533 days. Venkat estimates only about a 30-percent chance of success for the Mars crash-lander, while Hermes's near-Earth resupply would be more controllable. But both options require the single Chinese booster. Teddy Sanders rejects the Rich Purnell Maneuver because it endangers all six Hermes astronauts rather than only Watney, despite objections from Mitch Henderson and Annie Montrose.

Watney also writes personal messages for his crewmates in case he dies. On Hermes, Vogel receives a disguised image attachment apparently from his wife. Johanssen identifies it as an ASCII text file containing the Rich Purnell flight calculations. Vogel verifies the course and shows Lewis and the crew. Lewis will proceed only if everyone agrees, allowing twenty-four hours to reconsider the risks and possible consequences for disobeying NASA. The crew chooses the maneuver. Johanssen disables the priority remote-override mechanism across the redundant flight computers and radio systems, and Hermes deliberately changes course. Mission Control detects the 27.812-degree rotation and receives a message praising Rich Purnell. Teddy confronts Mitch, suspecting that he leaked the information but lacking proof. With Hermes already committed, NASA must organize the near-Earth resupply and Watney's trip to the MAV. The chapter ends with Mitch defending the crew's decision and criticizing Teddy.

On Sol 192, Watney learns that Hermes will return for a flyby rather than enter Mars orbit. He must reach the Ares 4 Mars ascent vehicle (MAV) at Schiaparelli, about 3,200 kilometers away, then launch while Hermes passes. He estimates forty to fifty sols of driving and up to forty-five more for MAV modifications, so he plans to survive for about one hundred sols away from the Hab. With the Hermes flyby scheduled for Sol 549, he must depart by Sol 449. The Ares 4 MAV's air tanks are empty, and he has 257 sols to prepare. NASA proposes towing Rover 1 as a pressurized trailer behind his modified Rover 2. The trailer must house the atmospheric regulator, oxygenator, and water reclaimer, all of which require continuous power, while the rovers also carry his supplies and Pathfinder.

NASA's plan calls for removing a section of the trailer roof, at least 2.5 by 2 meters, by drilling 760 closely spaced holes along an 11.4-meter cut and then chiseling out the material between them. Each hole takes about 160 seconds, but the normal rock-drill batteries last only 240 seconds and require lengthy recharging. Watney adapts one drill to use a rover's 36-volt charging cable, stepping the voltage down to 28.8 volts and combining three three-amp breakers to provide the needed nine-amp protection. He marks the proposed cut with string from Martinez's cot, lets NASA inspect it through Pathfinder's camera, and begins drilling. The work is tiring and requires occasional cooling. By the end of Sol 196 he has drilled 488 of the planned 760 holes; he has not yet removed the roof section or installed the life-support equipment. During this period, tests on the Hab soil also reveal that some bacteria survived the decompression, though Watney's explanation involving protected pockets of ice is only a hypothesis.

On Sol 196, the drill briefly stops and trips his breakers. Watney resets them and finishes his day's work, but NASA no longer answers his messages. Rover diagnostics show Pathfinder stopped responding at approximately 13:30, when the drill failed. Inspecting Pathfinder, Watney finds its power lead detached and its insulation melted. He reconstructs the accident: with its protective cowling removed, the powered drill touched his metal workbench; electricity traveled through conductive Mylar from Pathfinder's landing balloons into the probe's hull and sensitive electronics, then out its negative power lead. Pathfinder, designed for 50 milliamps, received about 9,000 milliamps before the breakers tripped. It is destroyed, and the chapter ends with Watney again unable to communicate with Earth.

After Pathfinder's electrical destruction, Watney spells a Morse-code message with rocks saying the probe is dead and he will continue toward the Ares 4 MAV. He cannot receive a reply and pauses trailer construction while designing the mobile life-support system himself. The three Hab systems would consume 69.2 kilowatt-hours per sol at their rated load, while the rover batteries store only 18 kilowatt-hours. He decides he can leave the water reclaimer behind: his remaining 620 liters at three liters per sol would last 206 sols, longer than the planned one-hundred-sol absence. The oxygenator also uses far less power for one person than its six-person design rating. Rather than run it continuously, he plans to store carbon dioxide removed by the atmospheric regulator and periodically stop to generate more oxygen. His two tanks hold 50 liters of liquid oxygen, enough for about eighty-five sols if used continuously.

The atmospheric regulator ordinarily draws 21.5 kilowatt-hours per sol, largely to warm the frigid air returning from its separation cycle. With that heater off, its measured draw falls to one kilowatt-hour per sol. Watney proposes using the radioisotope thermoelectric generator (RTG), which produces approximately 1,400 watts of excess heat, to reheat the air through a buffered hot-water system. He retrieves the RTG and successfully tests water heating, but does not yet install a complete rover heating system. To evaluate towing, he loads the trailer with roughly 1,200 kilograms of rocks; the rovers travel just 57 kilometers on a full 18-kilowatt-hour charge. At a conservative 50 kilometers per travel sol, stopping every two or three sols to run the oxygenator would extend the 3,200-kilometer journey to roughly ninety-two sols. While moving the rocks, he injures his back and spends time recuperating, including taking hot baths warmed by the RTG.

To improve the energy budget, Watney experiments with carrying twenty-eight solar panels rather than the fourteen used on his Pathfinder trip. Roof storage alone is inadequate, so he restores the trailer's battery, removes the rover's saddlebags, and builds side brackets from spare MAV landing struts. He successfully tests a stowage arrangement for twenty-eight panels, with space for a twenty-ninth, but returns the panels to the farm afterward. He also strips redundant seats, trailer controls and trailer life-support components while keeping the trailer computer as a spare. Two nine-kilowatt-hour Hab batteries fit inside the cleared trailer, raising available storage to 36 kilowatt-hours; the wiring tests successfully. He estimates this could allow up to 100 kilometers of driving on four of every five sols, reserving the fifth for oxygen production. The chapter ends with Watney worried about the Chinese launch of the Hermes resupply probe, scheduled in two days if there are no delays. He cannot learn its outcome until reaching Schiaparelli.

As Hermes approaches Earth for its gravity-assist resupply, the ship stops rotating so it can dock with the incoming probe. Lewis speaks with her husband Robert over a nearly real-time video connection, while the other crew members have brief calls with relatives. Teddy Sanders and Venkat Kapoor arrive in China, where CNSA employee Su Bin Bao helps them travel to Jiuquan. Chinese director Guo Ming reports successful collaboration between American and Chinese engineers, although Mitch Henderson has made himself unpopular. Vogel speaks with his wife Helena about their children and his ailing mother, whose memory is failing. Beck tells his sister Amy that he will wait in a suit in case the probe cannot dock. Martinez's wife Marissa is upset that he volunteered to extend the mission by 533 days, leaving her to raise their young son David without him for much longer.

During a televised interview, Venkat explains why the Taiyang Shen booster is necessary: Hermes will not enter Earth orbit and moves too fast for an ordinary launch vehicle to match. JPL's resupply probe was assembled in only thirty days and carries food and other necessities, a small maneuvering system, and no automated guidance system. Martinez must steer it to Hermes remotely. If it cannot dock, Beck may have to retrieve it by EVA and, as a final backup, carry its supplies aboard in several trips. In a separate call, Johanssen tells her father that Lewis has selected her as the sole survivor if the resupply fails because she is young, small, and qualified to get home. The other five crew members would take lethal pills immediately to preserve food. Even on reduced rations, the remaining provisions could last Johanssen only about nine months, against a seventeen-month return. Her father realizes she intends to rely on the bodies of the dead for additional food. Johanssen says she does not believe NASA knows about the contingency plan.

At Jiuquan, the Chinese booster successfully launches the American-built Hermes resupply probe. Zhu Tao, however, laments that the original Taiyang Shen scientific probe will remain in storage after years of development, even though the cooperation has earned China an Ares 5 crew seat. Later, the probe approaches Hermes at 2.3 meters per second. With Beck ready in Airlock 3 and Vogel standing by as his backup, Martinez remotely reduces its speed to 0.9 meters per second and guides it to Docking Port A. The automated capture system secures the probe and confirms a tight seal; neither EVA specialist needs to intervene. Lewis orders the crew to unload and inspect the supplies. The chapter ends with Martinez teasing Johanssen about the grim survival plan she discussed with her father.

By Sol 376, Watney finishes the roof opening in the trailer and installs a flexible canvas enclosure cut from a pop-tent. He prepares valve passages and an external-component shelf for the atmospheric regulator, though the actual equipment transfer remains ahead. He builds a thermal reservoir with the radioisotope generator submerged in twenty liters of water and passes the regulator's cold return air through perforated tubing. The test works. He also develops a route to Schiaparelli through Acidalia Planitia, Mawrth Vallis and Arabia Terra, accounting for substantial elevation changes and roughly 1,850 kilometers of difficult terrain. He jokingly argues that commandeering the Ares 4 MAV without permission would make him a space pirate. This is his own interpretation, not an established legal finding.

For a more comfortable place to live while the batteries charge, Watney expands the remaining pop-tent into a collapsible bedroom attached to the rover airlock. It needs thirty square meters of canvas, so he deliberately depressurizes the Hab and removes material from the dome, then shortens and reseals the remaining structure. His first low-pressure test reveals leaks, which he traces with fine Martian dust and seals. The Hab subsequently holds full pressure for an hour and remains airtight overnight. Inside it, he assembles the larger bedroom from two tent floors and new canvas, pressure-testing it with an EVA suit at 1.2 atmospheres. A separate hour-long test succeeds after attachment to the rover. Because the bedroom occupies the rover's sole airlock, he cannot test it overnight without remaining inside.

On Sol 390, he regards the rover's structural preparations as complete, but still needs to transfer and verify equipment, select cargo and finish route planning. His inventory includes 1,692 potatoes; 620 liters of water; fourteen liters each of liquid oxygen and nitrogen; 418 hours of emergency carbon-dioxide filters; 36 kilowatt-hours of battery storage; capacity for twenty-nine solar cells; and an RTG heating reservoir. He plans to leave on Sol 449, giving him fifty-nine sols for final preparation. Although he has wanted to leave Mars since Sol 6, he is apprehensive about leaving the Hab. The chapter ends with a joke about Apollo astronauts, not with his departure.

Preparing the two-rover convoy, Watney puts critical equipment and the full 620-liter water supply in the driving rover because a breach in the trailer can be isolated. The trailer holds the atmospheric regulator, oxygenator, Hab batteries and RTG heat reservoir; most potatoes remain frozen outside in the saddlebags. On Earth, Venkat reassigns Mindy Park to monitor Watney exclusively by satellite, even though she regards it as a demotion. Watney moves the disassembled regulator and oxygenator from the Hab to the trailer, installs the external atmospheric regulator component (AREC), and successfully tests carbon-dioxide removal. The Hab, temporarily without its normal processing equipment, retains enough air for his short stay. He leaves the rover's life support running overnight for another test.

The first full deployment of Watney's enlarged bedroom fails when a wall-to-ceiling seam ruptures and empties the rover's air. He survives because he is wearing an EVA suit. After reinforcing the failed seam with additional canvas and sealing resin, he repeats the test and the bedroom holds pressure for eight hours. Meanwhile, Martian meteorologist Randall Carter informs NASA of a slowly moving dust storm in Arabia Terra. Its winds are not the principal danger. Dense suspended dust has reduced sunlight there to about 20 percent of normal. The rover could require five times as long to recharge, turning the estimated forty-five-sol journey into approximately 225 sols and making Watney miss Hermes. NASA cannot warn him without Pathfinder, and its satellites will lose sight of him inside the storm. On Hermes, the crew reports declining reactor cooling efficiency, worn life-support filters, and an overheated bunk room. Lewis rearranges the sleeping quarters while the crew continues managing systems well beyond the ship's intended service interval.

Watney loads the convoy for a five-sol trial close to the Hab, substituting 600 kilograms of rock ballast for most of the water. He averages 93 kilometers of travel per sol on the favorable local terrain. When the bedroom proves too cold, he repurposes the rover heater's fan to circulate RTG-warmed air. He develops a routine for deflating and stowing the bedroom, driving about four hours, deploying the solar panels, and then using a stationary fifth 'Air Day' to run the oxygenator on stored carbon dioxide. This integrated test succeeds, but does not establish how the rover will perform on difficult terrain or in the unseen dust storm.

On Sol 449, Watney finishes packing his water and potatoes, which he has cooked and refrozen to make them more digestible, and checks the vehicle systems. He shuts down the stripped Hab, following the intended final-mission shutdown procedure as a personal acknowledgment of the Ares 3 mission he lost. He then enters the rover with fully charged batteries and leaves for Schiaparelli. The final entry states he has forty-five sols of driving ahead; his route and survival remain uncertain.

By Sol 458, Watney reaches Mawrth Vallis after ten sols on the road. His equipment is functioning, and an Air Day every fifth sol gives him time to run the oxygenator and rest while the solar panels charge. He crosses Mawrth Vallis's relatively flat floor and leaves Acidalia Planitia behind. In an interview, Venkat Kapoor tells Cathy Warner that a widespread dust storm in Arabia Terra has reduced sunlight to 20 percent of normal. NASA cannot warn Watney after the loss of Pathfinder, and the slowly increasing dust may be too subtle for him to notice before he is far inside the storm. NASA estimates that he will enter its edge around Sol 471. Meanwhile Watney, unaware of the storm, navigates using a homemade sextant and sightings of Deneb to determine latitude, and the predictable setting of Phobos and a clock to calculate longitude. Mindy Park decodes his rock message forecasting an arrival around Sol 494 and notes the approaching storm.

Watney climbs out of Mawrth Vallis and into Arabia Terra, where crater rims and elevation changes complicate his route. He passes between Rutherford and Trouvelot craters, reports 1,440 kilometers traveled on his fourth Air Day, and continues collecting geological samples that he acknowledges may have to be abandoned because the modified Ares 4 ascent vehicle has limited mass allowance. On Hermes, Lewis worries that entering the storm could prevent his arrival; Martinez insists Watney is capable of surviving but offers no technical rescue. As Watney approaches Marth Crater, he reports 1,435 kilometers still to travel and notices that his solar panels are producing progressively less energy. He initially assumes an equipment issue and checks their connections and cleanliness.

On Sol 474, Watney navigates into the rim of Marth Crater and stops early rather than attempt the dangerous slopes. After obtaining another position fix from Phobos and Deneb, he realizes he has reached the crater nearly head-on. From a walk to the rim, he observes that the eastern horizon is substantially hazier than the west, and he connects that asymmetry with his declining solar output. He concludes that he has already been inside a dust storm for several sols and that conditions worsen eastward toward Schiaparelli. He does not know its boundaries or movement, so he has not chosen an escape direction by the chapter's end. Mindy discovers that he has stopped and decodes his new Morse-code message, 'DUST STORM. MAKING PLAN.' She immediately calls Venkat.

On Sol 476, Watney treats the dust storm as a measurable reduction in solar power rather than a wind hazard. He needs sufficient electricity to travel and replenish oxygen, so entering a dense part of the storm could strand or kill him. He plans to leave solar panels and time-stamped recording devices at points along an eighty-kilometer north-south line, then compare their midday power output. He builds two loggers from spare EVA-suit cameras, meters, batteries and resistors. After a day of measurements, he finds that efficiency at his camp has fallen from 97 to 92.5 percent, indicating that the storm is moving west. The three simultaneous readings show power losses of 12.3 percent in the north, 9.5 percent at the midpoint, and 6.4 percent farther south. He therefore drives south to avoid the denser portion of the storm, repeatedly checking his charging efficiency. The detour costs travel time, but he preserves his planned oxygen-production days rather than risk running short of air.

By Sol 484 Watney measures 100 percent solar efficiency, concluding that he has passed south of the storm. He has traveled about 540 kilometers due south and is in Terra Meridiani, about 1,030 kilometers from Schiaparelli. He recalculates his arrival for approximately Sol 498, a four-sol delay that would leave forty-four sols for MAV modifications before the Sol 549 Hermes flyby. Opportunity is about 300 kilometers away and might allow him to restore contact with Earth, but he rejects that diversion because the functioning MAV communications system is closer in time. He also plans to move the atmospheric regulator and oxygenator into his sealable temporary bedroom after arrival, using the trailer as a permanent living area and workshop. This reconfiguration has not yet happened.

Approaching the Schiaparelli Basin, Watney identifies a smaller 'Entrance Crater' marking a route down the northwest rim. He estimates the Entrance Ramp drops about 1.5 kilometers over at least 45 kilometers and assumes its average gentle slope will be manageable. The narrative then leaves his log-entry perspective to explain that wind deposition and differential compaction have made the ramp irregular, with hard and very soft material hidden beneath surface dust. On Sol 497, while he carefully descends, the rover's wheel sinks at an unseen transition and the vehicle rolls. The roof-mounted solar panels scatter, the towing clamp and connecting hoses snap, and the trailer overturns onto its balloon roof. The rover tumbles farther before stopping on its side. Its automatic valves close, preserving rover cabin pressure. The chapter ends with Watney still alive, but the condition of the overturned trailer and life-support equipment has not yet been assessed.

NASA sees the overturned rover, inverted trailer and scattered solar panels in satellite images but cannot initially determine Watney's condition. He reports from inside the rover that he is uninjured and the cabin still holds pressure. The damaged link has automatically isolated the trailer, leaving him with about forty sols of stored oxygen and 483 hours of carbon-dioxide filtering across the rover and EVA suits. Outside, he finds that three of his twenty-nine solar cells are cracked beneath the rover, the rover's tow hook is broken, and the trailer rests on its flexible inflated roof. The trailer balloon has not ruptured. He spells 'ROLLED. FIXING NOW.' in rocks so Mindy can relay that he is active, although NASA has no detailed assessment.

Watney initially prioritizes the trailer, but decides he needs the rover upright to recover it. He anchors a long power cable to a drill bit driven into rock, attaches the other end to the rover's upper frame and pulls the cable sideways for enough leverage to tip the vehicle back onto its wheels. Rover diagnostics pass. The next day he digs a large hole near the inverted trailer's nose, then tows the trailer with the rover so the nose drops into the hole and the vehicle turns back onto its wheels. Early shadows from the Schiaparelli crater wall limit his working time. Inside the trailer, Watney discovers the atmospheric regulator and oxygenator remain functional. Without the rover's carbon dioxide to process, the regulator stopped sending cold air through the RTG water-heating reservoir, leaving the trailer extremely hot. The reservoir has spilled its water but is refillable. The separation hoses released without damage; he reconnects them, transfers the intact trailer tow hook to the rover, and restores shared life support and towing. The recovery has cost four sols.

To avoid another rollover on the irregular Entrance Ramp, Watney cuts his driving speed from 25 to five kilometers per hour. NASA receives his 'ALL BETTER NOW' message while engineers are still preparing the MAV modifications. After eight cautious driving hours, he reaches the level Schiaparelli Basin, where the crater wall no longer shortens his charging day. He eats his reserved recovery meal. On Sol 503 a shortened drive leaves him 148 kilometers from the MAV. On Sol 504 he travels another 90 kilometers, estimates about fifty kilometers remain, and detects a weak homing beacon that NASA has configured to imitate the Ares 3 Hab signal. He reports 'GOT BEACON SIGNAL.' On the following sol, narration shifts away from his log to show the rover arriving twenty meters from the Ares 4 MAV. Watney exits, celebrates and climbs into its airlock, sealing the door. The chapter ends there; communication through the MAV and its subsequent modification have not yet been depicted.

On Sol 505, Watney reaches the Ares 4 Mars ascent vehicle (MAV), checks its systems and supplies it with oxygen and nitrogen from his rover. The MAV has no onboard air supply until connected to surface equipment. Over a fourteen-minute one-way communication delay, he tells Houston his life-support machinery still works, he has 550 liters of water and enough food to reach the Sol 549 Hermes flyby. NASA asks him to conserve water and keep the rover radio operating. Bruce Ng explains to Venkat Kapoor that the MAV's normal 4.1-kilometer-per-second orbital capability cannot meet Hermes's approximately 5.8-kilometer-per-second flyby. To increase fuel, Watney must electrolyze water and eventually urine. NASA calculates that sixty kilograms of hydrogen will produce 780 additional kilograms of fuel, but the MAV must also fall from more than 12,600 kilograms to about 7,300 kilograms.

JPL's procedures strip the MAV of most equipment and redundancy: five unused acceleration seats, cargo allowances, life-support equipment, control panels, most batteries, backup communications, thrusters, an auxiliary fuel pump and one first-stage engine. Martinez will pilot remotely from Hermes while Watney wears his EVA suit. Watney also removes the nose airlock, windows and Hull Panel 19, to be replaced by Hab canvas, and a removable rear panel. Bruce estimates a roughly four-percent chance of failure. Watney rejects a proposed trailer-to-workshop conversion and instead uses the rover's inflatable bedroom and the still-sealed MAV as workspaces. He carries out tests of his aging rover and fully functional MAV before dismantling the latter.

Watney extracts hydrogen using electrolysis inside the trailer: he fills it with low-pressure oxygen, splits water, uses the regulator to remove oxygen, collects the remaining hydrogen through the rover airlock holding tank, and transfers it to the MAV fuel plant. Aboard Hermes, Martinez repeatedly practices remote ascent, while Beck prepares a 214-meter tether and maneuvering unit to retrieve Watney if their relative velocity is low enough. Direct communication between Watney and Hermes becomes available when they are approximately thirty-five light-seconds apart. Six sols before launch, Watney finishes the alterations; subsequent checks cannot reproduce the first-stage ascent conditions. Hermes's crew rehearses the intercept and NASA prepares to observe, but Houston's transmission delays prevent useful real-time intervention.

Four hours before launch, Watney is strapped into his EVA suit inside the radically lightened MAV. He has eaten his last packaged meal, left behind geological samples, and has only forty-one potatoes remaining. There is no delay or abort option because Hermes cannot wait. The chapter ends with Watney acknowledging that he will leave Mars that day, whether or not he survives the ascent; the launch itself has not occurred.

As people around the world watch, the modified MAV launches from Mars with Martinez remotely piloting and Watney strapped into an acceleration couch. High acceleration prevents Watney from responding, and the canvas covering the removed forward hull tears during ascent. Atmospheric drag leaves the MAV below its planned course; Watney loses consciousness under approximately twelve g's. The vehicle reaches orbit, but Johanssen calculates an intercept miss of sixty-eight kilometers, even though the initial relative velocity would be eleven meters per second. The MAV no longer has maneuvering thrusters. With just thirty-nine minutes until closest approach, Lewis orders Hermes to use 75.5 percent of its remaining attitude-control fuel to correct the intercept distance. This brings the projected separation to zero but raises relative velocity to forty-two meters per second, too fast for Beck to retrieve Watney.

Johanssen detects Watney's biomonitor, and he regains consciousness with chest pain. He proposes puncturing his EVA glove to propel himself toward Hermes, but Lewis refuses the uncontrolled maneuver. She instead proposes intentionally venting Hermes through its forward vehicular airlock (VAL). Calculations suggest an impulse of about twenty-nine meters per second, leaving roughly thirteen meters per second of relative velocity. Vogel prepares a small explosive charge to open the inner VAL door. Johanssen arranges remote detonation through an electrical panel, Martinez seals the reactor compartment and maneuvers the ship, and Beck secures the outer VAL door open before returning across the hull to Airlock 2. The bridge is sealed to preserve breathable air.

The venting maneuver works. Hermes is projected to pass within twenty-two meters of the MAV at twelve meters per second relative velocity. Beck launches himself from Airlock 2, uses his maneuvering unit (MMU) to reach the tattered MAV canvas, and clips himself to Watney. As the tether nears its limit, they push away from the MAV and Beck uses the last of his MMU fuel, reducing their velocity relative to Hermes to five meters per second. Vogel then applies controlled friction to the tether, allowing Hermes to bring them to matching velocity without tearing the line or suit attachments. He reels them into Airlock 2, and Lewis confirms all six crew members safely aboard. The successful rescue triggers celebrations on Earth.

Watney's final entry is dated Mission Day 687 on Hermes, corresponding to Mars Sol 549. He has two broken ribs from the ascent and receives medical care after the crew repressurizes the ship. He reflects on the efforts of his crewmates, NASA, JPL, the Chinese space program and the global public that made his survival possible. He attributes those efforts partly to a human impulse to help people in danger. The mission still has 211 days until Earth return, which is not depicted. Despite his injuries and the long journey ahead, Watney closes by calling this the happiest day of his life.