Rover (space exploration) it landed on the Martian Meridiani Planum on January 25, 2004 at 05:05 Ground UTC (about 13:15 local time), three weeks after its twin "Spirit" (MER-A) touched down on the other side of the planet. On July 28, 2014, NASA announced that "Opportunity", after having traveled over on the planet Mars, has set a new "off-world" record as the rover having driven the greatest distance, surpassing the previous record held by the Soviet Union's Lunokhod 2 rover that had traveled . () On 26 November 2011, NASA's Mars Science Laboratory mission was successfully launched for Mars. The mission successfully landed
Curiosity (rover) ("Mount Sharp"), at the center of the wide crater. Thus, it is believed that the rover may have the opportunity to study two billion years of Martian history in the sediments exposed in the mountain. Additionally, its landing site is near an alluvial fan, which is hypothesized to be the result of a flow of ground water, either before the deposition of the eroded sediments or else in relatively recent geologic history. According to NASA, an estimated 20,000 to 40,000 heat-resistant bacterial spores were on "Curiosity" at launch, and as much as 1,000 times that number may not have been