How does Mark prepare for the MAV's ascent to reunite with Hermes?

Mark drives one of the Ares 3 rovers 3,200km across rough terrain and Martian craters to the preselected Ares 4 site, in order to board the MAV that had been delivered in an earlier drop. The MAV would lift him into orbit so that the crew on the Hermes could make contact with him and pull him safely on board where he would reunite with his crew head home.