Sol 90. Watney has followed his rover tracks back through Lewis Valley, but now that he is in Acidalia Planitia, his outgoing tracks have been blown away. He plans to navigate by Phobos until he picks up the Hab’s beacon signal. Watney is feeling positive, and he’s begun taking soil and rock samples in case he makes it back to Earth. Collecting the samples makes him feel like a true astronaut again—he’s not just surviving, he’s doing his job.
Watney’s decision to start collecting rock samples shows that, unlike Dr. Shields feared, he has not given up hope of rescue. Up until this point, all of his energy has been focused on surviving on Mars, but in collecting samples (and, in Chapter 9, naming places) he’s doing the work of exploring a new land.
On Sol 92, Watney gets the Hab’s signal for a moment, then loses it. He notes that he’s still watching Lewis’ 1970s TV shows. On Sol 93, he gets a steady signal—he’s 24,718 m away, which puts him within a day’s travel. Watney’s back is aching, and he imagines Beck heckling him for not stretching and doing exercises. The cramped conditions of the rover remind Watney of a simulation in which the Ares 3 flight crew spent three days in an MAV. Watney wishes he were with his crewmates now.
Watney continues to maintain a sense of connection to life on earth by watching TV shows. Now, as he reminisces about the Ares 3 trainings and Beck’s insistence on proper exercise, Watney reveals a sense of nostalgia for his crewmates’ company and even for the less-than-ideal moments of the Ares 3 mission.
Sol 94. Watney is thrilled to be back in the Hab, where he has room to move around. The potatoes are growing well, and he adds his “manure” to them. Watney turns the Hab oxygenator and atmospheric regulator back on, adds his urine to the water reclaimer, and returns the cells to the solar array. He checks on the Hab’s electrical equipment. Watney removes the Pathfinder from the rover and leaves it outside, where it can communicate with NASA. Then he returns the RTG to the place where Lewis had buried it.
Back at the Hab, Watney goes from one set of routines to another—instead of driving and recharging the battery, he is now tending potatoes and checking the Hab life support. Though Watney earlier scoffed at NASA’s caution around using the RTG, he returns it to the place where Lewis buried it, suggesting that his apparent lack of concern about using a nuclear core may have been bravado.
Sol 95. Watney spends the day cleaning and repairing Pathfinder and Sojourner. He suspects NASA lost contact with them because Pathfinder’s solar panels became covered with dust and its battery ran down. Watney hooks the lander up to Hab power and uses Rover 1’s heater to warm up the lander’s electronics. When he wakes up the on Sol 96, the lander isn’t yet working—when it is, the antenna will change its angle to pick up signals from Earth. Sojourner also isn’t working. Watney tries not to worry. Then, the novel switches to a new format: the old Pathfinder Log, which is accessible since, unbeknownst to Watney, the battery has filled, and the lander acquired a signal.
So far, Watney has successfully solved every problem he’s faced, so when he starts cleaning Pathfinder, Weir has set up the reader to expect that dusting off the solar cells and recharging the battery will be enough to fix it. When it isn’t working the morning of Sol 96, the reader worries along with Watney—is this the one problem he won’t be able to solve? Then, with the change in structure, Weir creates a sense of dramatic irony and suspense: we know Pathfinder is working, but does Watney?