NASA selected Meridiani Planum as a landing site because of extensive deposits of a mineral called crystalline hematite, which usually forms in the presence of liquid water. Scientists had hoped for a specific landing site where they could examine both the surface layer that's rich in hematite and an underlying geological feature of light-colored layered rock. The small crater in which Opportunity alighted appears to have exposures of both, with soil that could be the hematite unit and an exposed outcropping of the lighter rock layer.
Challenger's 10th flight was to have been a six-day mission dedicated to research and education, as well as the deployment of the Tracking and Data Relay Satellite-B communications satellite.
Challenger's commander was Francis R. Scobee and the mission pilot was Michael J. Smith. Mission specialists included Judith A. Resnik, Ellison S. Onizuka and Ronald E. McNair. The mission also carried two payload specialists, Gregory B. Jarvis and Sharon Christa McAuliffe, who was the agency's first teacher in space.
Opportunity successfully landed on Mars January 25 (Eastern and Universal Time; January 24 Pacific Time). It will spend the next three months exploring the region surrounding what is now known as Challenger Memorial Station to determine if Mars was ever watery and suitable to sustain life.
Opportunity's twin, Spirit, is trailblazing a similar path on the other side of the planet, in a Connecticut-sized feature called Gusev Crater.
A composite image depicting the location of the Challenger Memorial Station can be found on the Web at:
NASA's Jet Propulsion Laboratory, Pasadena, Calif., is a division of the California Institute of Technology, also in Pasadena. JPL manages the Mars Exploration Rover mission for NASA's Office of Space Science in Washington, D.C.
Additional information about the project is available from NASA, JPL and Cornell University, Ithaca, N.Y., on the Internet at: http://www.nasa.gov/, http://marsrovers.jpl.nasa.gov and http://athena.cornell.edu.