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
SpaceX Red Dragon mission, as originally proposed by NASA Ames Research Center, were: A 2014 study of a potential 2021 NASA-funded "Red Dragon" mission suggested that it could offer a low-cost way for NASA to achieve a Mars sample return. In the concept, the "Red Dragon" capsule would be equipped with the system needed to return samples gathered on Mars, including a Mars Ascent Vehicle (MAV), an Earth Return Vehicle (ERV), and hardware to transfer the sample collected by a previously landed rover mission, such as NASA's planned Mars 2020 rover, to the ERV. The ERV would transfer the samples to high Earth