Chapter 9

On Sol 79, Mark Watney details his road routine: conserving water, collecting and deploying solar panels, swapping rover batteries, and enduring cramped conditions. He contemplates the future 3,200-kilometer journey to Ares 4 and the need to relocate major Hab systems to survive such a trek.

By Sol 80, navigation by landmarks fails on the featureless plains, so Watney uses Phobos’s motion and later a valley he dubs Lewis Valley. A small crater he calls the Lighthouse provides a reliable reference point, and Hamelin crater will guide him onward. On Sol 81 he enters rougher Ares Vallis terrain, slows to avoid larger rocks, reflects on his isolation, and steels himself to recover Pathfinder.

On Sol 82, guided by Twin Peaks, he finds Pathfinder and the nearby Sojourner rover. He stows Sojourner, then dismantles the lander by popping hinges and cutting sand-filled balloon remnants. Unable to lift the heavy central panel in his suit, he drags it to the rover and plans to mount it on the roof with a single tall stack of solar panels. He also devises a two-way comms plan using Sojourner’s wheels to spell messages if the lander’s radio works.

On Sol 83, Watney builds a four-meter, 30-degree rock-and-sand ramp to haul the 200-kilogram lander panel onto the rover roof, increasing his oxygen mix to endure the exertion. After lashing the payload and restacking the solar panels, he dismantles the ramp to protect the rover’s undercarriage and prepares to return to the Hab with the recovered probe.