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
Opportunity (rover) early June 2018, a large global-scale dust storm developed and within a few days the rover's solar panels were not generating enough power to maintain communications, with last contact on June 10, 2018. NASA stated they did not expect to resume communication until after the global dust storm subsided, but the rover kept silent even after the storm ended in early-October, suggesting either a catastrophic failure or a layer of dust covered its solar panels. The team remains hopeful that a windy period between November 2018 and January 2019 may clear the dust from its solar panels, as has happened