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
Mars 2020 that were under consideration for Mars 2020. A workshop was held on 8–10 February 2017 in Pasadena, California, to discuss these sites, with the goal of narrowing down the list to three sites for further consideration. The selected sites are: In November 2018, it was announced that Jezero crater was chosen as the planned landing site for Mars 2020 rover. A key mission requirement for this rover is that it must help prepare NASA for its Mars sample-return mission (MSR) campaign, which is needed before any crewed mission takes place. Such effort would require three additional vehicles: an orbiter, a