Mars rover to regain contact. Mars 2, Mars 3 were physically tethered probes; "Sojourner" was dependent on the Mars Pathfinder base station for communication with Earth; MER-A & B and "Curiosity" were on their own. Of these "Curiosity" is still active, and "Spirit", "Opportunity" and "Sojourner" completed their missions before losing contact. Seven rovers have been dispatched to Mars: "Examples Landed instrumentation" (Rovers) Mars rovers in development include: One experimental design, not proposed for any actual mission, is: NASA distinguishes between "mission" objectives and "science" objectives. Mission objectives are related to progress in space technology and development processes. Science objectives are met
Crewed Mars rover called MOLAB. One of the ideas for Molab was for it touch down on its wheels, what was called a "rover first" concept. MOLAB had a pressurized cylinder for crews to operate in a shirt-sleeve environment even on an extraterrestrial surface. For options for keeping track of location as the rover moves around Mars include: Navigation on Mars is noted as important issue for human missions to the planet. Celestial navigation, used for over 500 years on Earth, may provide a way of locating on the Mars surface to within about 100 meters (109 yards). Navigation is especially relevant to