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 the 2010s. The 1980s era Case for Mars design suggest a medium range rover with two compartments, one which could be depressurized and opened up to the Mars atmosphere, and a driving compartments which could remain pressurized during this time. The same study also suggested a bigger long duration rover with tracks and robotic arms, in addition to other types in that Mars surface human mission concept. Airlock design, especially for EVA is an area of study for pressurized rovers. Design ideas for crewed and/or pressurized rovers: Additional possible technologies: A 2004 analysis of a human Mars surface mission suggested