The Mars Exploration Rover 2 has been installed on the base petal of the lander and the solar arrays have been stowed for flight.

In the Payload Hazardous Servicing Facility, the Mars Exploration Rover 2 (MER-2) has been installed on the base petal of the lander and the solar arrays have been stowed for flight. The cruise stage is in the background. There are two rovers, identical to each other, and each will land at different regions of Mars. They are designed to cover roughly 110 yards each Martian day over various terrain. Each rover will carry five scientific instruments that will allow it to search for evidence of liquid water that may have been present in the planet's past. The first rover has a launch window opening May 30, and the second rover a window opening June 25.