In a fairly technical chapter, Watney describes in detail the chemical reactions necessary to create water for irrigation. He goes to great lengths to create sparks and maintain a flame, since NASA has designed most parts of the Hab to be fire-resistant. He also portions out very small amounts of hydrazine (essentially, rocket fuel) from the MDV, which he’ll then slowly “burn” in a controlled fashion, to produce water as a waste product. Watney knows the process is a dangerous, combustible one, so he moves carefully. But he realizes, after watching the reaction for some time, that some unburned hydrogen is slipping away from the flame and entering the “atmosphere” of the Hab. Hydrogen is extraordinarily flammable, and Watney moves to one of the rovers, parked outside the Hab, to figure out how to dissipate this flammable substance from his living space without setting it on fire.
Watney is successful in doing this, for a time. He moves the potato plants from the Hab to the rover, so he can begin dissipating some of the oxygen from the Hab and burning off the excess hydrogen, before returning the plants to the Hab, now with extra water from the controlled chemical reaction. But, after burning off part of the hydrogen, he comes to after a large explosion, with a ringing in his ears. Although he hasn’t punctured the Hab or damaged any sensitive equipment, he’s nearly killed himself, and he struggles to figure out why. As it turns out, some small amount of oxygen from his exhalation entered the Hab while Watney was conducting the hydrogen burn-off procedure. This excess oxygen altered the chemical makeup of the Hab enough to render it an explosive environment, and Watney considers himself lucky to have escaped. He still has his stores of potatoes in the rover, and he marvels at NASA’s design for the Hab, which appears to have protected the oxygenator, water reclaimer, and computer systems, even during the explosion.
The narrative switches back to Earth, where Venkat Kapoor, director of the Ares program, has a conversation with Teddy Sanders, the administrator of NASA. Kapoor wants NASA to release satellite images of the Ares 3 site, but Sanders demurs, saying that he can’t risk the bad press that might result from pictures of Watney’s body relayed to Earth. (For weeks, TV shows have been discussing the dust storm on Mars’s surface, the Ares 3 crew’s escape, and Watney’s being left behind, presumed dead.) Mindy Park, a satellite imaging specialist for NASA, is observing scans from the mission, when she realizes that the Ares 3 landing zone has altered somewhat since Watney’s supposed “death.” She calls Kapoor, who forwards this possibility to Sanders. Kapoor, with Park’s help and insistence, realizes that enough movement has occurred in the Ares 3 images to indicate that, indeed, Watney is still alive on the surface of the planet. Kapoor and Sanders (with Park’s input, and in consultation with Annie Montrose, the NASA press secretary) try to figure out what to do next; information about Watney’s survival will soon leak from NASA and become public. NASA also has a public responsibility not to keep secrets from American citizens, as administrators remind each other in Houston.
NASA begins the calculations necessary to formulate a plan to save Watney. They try to figure out if they can communicate with him, if he has enough food, water, and air on the planet, and if they can determine a rendezvous point on Mars, between the Ares 3 and 4 sites. Kapoor and Sanders also realize that Watney’s survival can be useful for NASA, which has received bad press from reports and analysis of his supposed death. The administrators hope that a plan to save Watney will also lead to additional NASA funding from Congress, which can support future Ares missions. Sanders announces in a televised press conference that the rescue of Mark Watney is now NASA’s number one aim. A flurry of publicity attends this announcement, as the whole of the US and much of the world marvels at Watney’s survival thus far in an inhospitable environment.
Although Mark Watney is a human being, his televised presence, on Earth, becomes a metaphor, perhaps a mixed one, for many viewers. Mark seems to embody pure human perseverance, and perhaps, too, American ingenuity in the face of danger. Watney is not able, at this point in the novel, to communicate with Earth, but when he does, he doesn’t pity himself, nor does he blame the crew for leaving him behind. (Indeed, he tells Lewis and his crewmates that this was the correct course of action; they had to save themselves, and they thought he was a goner.)
Watney’s humor in the face of the gravest of odds makes him an easy stand-in for abstract ideas: American heroism, grit, and stick-to-it-iveness. One theme of the novel is the ability of hard-edged scientific rationalism to triumph over seemingly intractable problems. When Watney finds himself without enough water to irrigate his potato crops, he could give up. After all, the Hab wasn’t designed for anything like the project he’s now undertaking. But Watney takes the problem one step at a time, reducing it to smaller problems he does know how to solve. Watney also possesses a preternatural ability not to place the cart in front of the horse: he doesn’t worry about potential problems down the line, but only the task immediately before him. This ability serves him extraordinarily well in space, allowing him to remain calm even in the tightest of scrapes.
Of course, Watney is the protagonist of the novel, the main character around whom the narrative revolves. In this way the novel has no human antagonist, but it does have what we might call an anthropomorphized antagonist, in the form of Mars itself. Watney jokes, throughout, about his frustrations with Mars: the fact that he is the “king” of the entire planet, and that Mars seems to do whatever it can to kill him. Naturally, Mars has no emotion, no desires; but Mars represents, for Watney, an unending series of challenges. It will take every ounce of Watney’s cleverness and skill to compete with Mars and to “win” in their confrontation: to be able to make it back to Earth alive.