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,
Mars Exploration Rover Mars Exploration Rover NASA's Mars Exploration Rover (MER) mission is an ongoing robotic space mission involving two Mars rovers, Spirit and Opportunity, exploring the planet Mars. It began in 2003 with the launch of the two rovers: MER-A "Spirit" and MER-B "Opportunity"—to explore the Martian surface and geology; both landed on Mars at separate locations in January 2004. Both rovers far outlived their planned missions of 90 Martian solar days: MER-A "Spirit" was active until 2010, while MER-B "Opportunity" is still active in 2018, and holds the record for the longest distance driven by any off-Earth wheeled vehicle. The mission's