Kevin Burke checks the closure of the lander petals and rover egress hardware around the Mars Exploration Rover 2 (MER-A.

Kevin Burke, with the Jet Propulsion Laboratory, Pasadena, Calif., checks the closure of the lander petals and rover egress hardware around the Mars Exploration Rover 2 (MER-A). The lander and rover will subsequently be enclosed within an aeroshell for launch. The MER Mission consists of two identical rovers 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. Identical to each other, the rovers will land at different regions of Mars. Launch date for this first of NASA's two Mars Exploration Rover missions is scheduled no earlier than June 6.