Back at NASA, Venkat and Mindy are looking at the most recent satellite imagery from Mars. After checking out Mark's latest progress, Venkat tells Mindy that her "sole responsibility is watching Mark Watney" (21.24).
Meanwhile, Mark has just run his final, successful test of the rover. Granted, the pop-tent does pop, but it's nothing that a few patch-kits won't fix.
If Mark was still in contact with NASA, however, he'd be getting worried around now. The scientists have just noticed a "low-velocity dust storm" currently plowing through his planned route (21.84). It won't be windy enough to cause damage, but it will certainly prevent light from reaching his solar cells.
The Hermes crew is preparing for their moment of truth, as well. As a side-note, Beck and Johanssen are now officially a couple. Adorable.
After exhaustively testing every system and cooking a ton of potatoes, Mark finally sets off on his journey. The moment of truth is here.