KENNEDY SPACE CENTER, Fla. - In the Payload Hazardous Servicing Facility, workers check alignment of the Rover Equipment Deck (RED) on one of the Mars Exploration Rovers (MER) with the Warm Electronics Box (WEB). Processing of the rovers, plus cruise stage, lander and heat shield elements, is ongoing. Set to launch in 2003, the MER Mission will consist of two identical rovers designed to cover roughly 110 yards each Martian day. 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 rovers will be identical to each other, but will land at different regions of Mars. The first rover has a launch window opening May 30, and the second rover a window opening June 25, 2003.