Sol 197. Watney writes that he keeps endangering himself through his own “stupidity.” He decides he’ll continue with the trip to the Ares 4 MAV and do the rover modifications without NASA’s help. Once he’s at the MAV, he’ll be able to communicate with them again. To run the “Big Three” he will need energy: 69.2 kilowatt-hours per sol. Watney decides he’ll refer to kilowatt-hours per sol as “pirate-ninjas.” Since he has enough water to last through the trip, he can cut that back on energy by not using the water-reclaimer to process urine.
Watney’s comment highlights how taking his surroundings for granted frequently puts him at risk. He can no longer afford to be careless. Yet his decision to proceed with the rover modifications and the trip to Ares 3 shows that he is far from losing hope. In inventing the new unit of measurement, “pirate-ninjas,” Watney once again uses humor to cope with a stressful situation.
Sol 198. Watney realizes that because he is one person, not six, the oxygenator is only working one-sixth as hard as it’s supposed to and doesn't require as much energy as he’d thought. Most of the 21.5 “pirate-ninjas” that the atmospheric regulator uses is spent heating the Hab’s air. Sol 199. Watney decides he’ll conserve energy by running the oxygenator only on designated rest days—not while driving. He’ll use the RTG to heat the Hab’s air so that the atmospheric regulator doesn’t work as hard.
Once again, Watney finds a way to use the fact that he is the only person on Mars to his advantage: the tactic of running the oxygenator only on rest days wouldn’t work if all six members of the Ares 3 crew had been stranded. Watney’s decision to use the RTG again shows that he is as willing as ever to take risks in order to make it back to Earth.
Sol 200. Watney loads the rover and “trailer” with rocks and tests how much weight they can haul and how many pirate-ninjas they use. He calculates that it will take him 92 sols to get to the Ares 4 MAV. Sol 201. Watney has pulled something in his back, but takes Vicodin and drives out to retrieve the RTG. Back in the Hab, he experiments with wrapping plastic tubing around the RTG and running water through it—it heats the water to a consistent temperature. Watney uses the hot water to take a bath.
The first time Watney dug up the RTG, he was fairly cautious about using it (after all, he returned it to the place where Lewis had buried it). Now, Watney is a bit more cavalier—or, perhaps, months on Mars have made him more pragmatic. He has little to lose and everything to gain from using the RTG—why not use it to take a bath?
Sol 207. Watney has spent a week resting his back. He figures out that if he can take 28 solar panels and two of the Hab’s batteries on the trip, he can make it to Schiaparelli in just 45 days. Sol 208. Watney experiments with different ways to carry the panels, and decides he’ll build “shelves” attached to the Rover’s undercarriage, then stack and tie down the panels. Sol 209. Watney successfully builds the shelves.
While Watney has become less cautious in some ways, he has become more cautious in others—it’ll be hard for him to do anything if he’s injured, so he takes the time to let his back heal. Yet even while he’s resting, Watney’s mind is at work, finding new ways to solve problems and modify the rovers.
Sol 211. Watney cleans out the rovers, removing everything he won’t need on the trip, then moves in two of the Hab’s batteries. Watney knows the Hermes resupply probe will be launched in two days, and he hopes that it goes smoothly—he’ll feel to blame if his crewmates die in their attempt to rescue him.
Watney worries about his crewmates, but the reader knows that if this probe launch fails, Watney won’t know unti he reaches the Ares 4 MAV site. Weir once again builds suspense using dramatic irony, and this time, Watney is the one in the dark.