Cornell University has been selected by NASA to provide the scientific instruments and lead the science team for the next mission to the surface of Mars. The space agency announced today that a rover mission will be launched on June 4, 2003, and the spacecraft will land on Mars on Jan. 20, 2004. The mission, which will carry a large roving vehicle to the surface of Mars, was chosen by Edward Weiler, NASA associate administrator for space science, after an intensive two-month study of the two competing candidates, the rover and a scientific orbiter.