Curiosity (rover) conditions favorable for microbial life, including investigation of the role of water; and planetary habitability studies in preparation for human exploration. In December 2012, "Curiosity" two-year mission was extended indefinitely. On August 5, 2017, NASA celebrated the fifth anniversary of the "Curiosity" rover landing and related exploratory accomplishments on the planet Mars. The rover is still operational, and as of , "Curiosity" has been on Mars for sols ( total days) since landing on August 6, 2012. "(See current status.)" "Curiosity" design will serve as the basis for the planned Mars 2020 rover. As established by the Mars Exploration Program,
Opportunity mission timeline Opportunity mission timeline Opportunity, MER-B (Mars Exploration Rover – B), is a robotic rover active on the planet Mars since 2004. Launched on July 7, 2003, "Opportunity" landed on Mars' Meridiani Planum on January 25, 2004 at 05:05 Ground UTC (about 13:15 Mars local time), three weeks after its twin "Spirit" (MER-A), also part of NASA's Mars Exploration Rover Mission, touched down on the other side of the planet. While "Spirit" became immobile in 2009 and ceased communications in 2010, "Opportunity" remains active as of December 11, 2017, having already exceeded its planned 90 sol (Martian days) duration of activity