Opportunity (rover) Opportunity (rover) Opportunity, also known as MER-B (Mars Exploration Rover – B) or MER-1, is a robotic rover active on Mars since 2004. Launched on July 7, 2003 as part of NASA's Mars Exploration Rover program, it landed in Meridiani Planum on January 25, 2004, three weeks after its twin "Spirit" (MER-A) touched down on the other side of the planet. With a planned 90 sol duration of activity (slightly more than 90 earth days), "Spirit" functioned until getting stuck in 2009 and ceased communications in 2010, while "Opportunity" was active as of June 10, 2018 when a dust storm
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