Curiosity (rover) arm operations were cleared to continue, but drilling remained suspended indefinitely. The "Curiosity" team continued to perform diagnostics and testing on the drill mechanism throughout 2017. "Curiosity" has an advanced payload of scientific equipment on Mars. It is the fourth NASA unmanned surface rover sent to Mars since 1996. Previous successful Mars rovers are "Sojourner" from the Mars Pathfinder mission (1997), and "Spirit" (2004–2010) and "Opportunity" (2004–present) rovers from the Mars Exploration Rover mission. "Curiosity" is long by wide by in height, larger than Mars Exploration Rovers, which are long and have a mass of including of scientific instruments. In
Mars Exploration Rover "Opportunity" marked six years on Mars, respectively. On January 26, NASA announced that "Spirit" will be used as a stationary research platform after several months of unsuccessful attempts to free the rover from soft sand. NASA announced on March 24, 2010, that "Opportunity", which has an estimated remaining drive distance of 12 km to Endeavour Crater, has traveled over 20 km since the start of its mission. Each rover was designed with a mission driving distance goal of just 600 meters. One week later, they announced that "Spirit" may have gone into hibernation for the Martian winter and might not