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 Crewed Mars rover Crewed Mars rovers are vehicles for transporting people on the planet Mars, and have been conceptualized as part of human mission to that planet. Two types of crewed Mars rovers are pressurized and unpressurizedunpressurized designs may have open seating for a crew in Mars space suits, and another style has a pressurized interior for people to work without a space suit. Pressurized rovers have been envisioned for short trips from a Mars base, or they may be equipped to be more of a mobile base or laboratory. They are also called "manned Mars rovers" Crewed Mars rovers