Another component of the Mars Exploration Rover-1 mission is moved into KSC's Multi-Payload Processing Facility. While at KSC, the rovers, aeroshells and landers will undergo a full mission simulation. All of these flight elements will then be integrated together. After spin balance testing, each spacecraft will be mated to a solid propellant upper stage booster that will propel the spacecraft out of Earth orbit. Approximately 10 days before launch they will be transported to the launch pad for mating with their respective Boeing Delta II rockets. The rovers will serve as robotic geologists to seek answers about the evolution of Mars, particularly for a history of water. The rovers will be identical to each other, but will land at different regions of Mars. Launch of the MER-1 is scheduled for May 30. MER-2 will follow June 25.