A satellite zooming around Mars spotted a lone machine, the Curiosity Rover, exploring the rugged Martian terrain. The car-sized rover, which has traveled almost 13 miles on Mars over the last seven years, is now carefully inching up the base of Mount Sharp, a 3.5-mile tall mountain sitting in the middle of the sprawling Gale Crater. The rover has been busy scouring rock samples in an area that planetary scientists suspect was once blanketed in wet clay."It's just one of many stops the rover has made in an area referred to as the "clay-bearing unit" on the side of Mount Sharp," NASA wrote on Friday.The Curiosity Rover on Mars.Image: NASA / JPL-CaltechA prominent ridge, called the Vera Rubin Ridge, can be seen cutting to the left (or northwest) of the rover, while ripples of dark sand are on found the right of the six-wheeled robot. The rover looks like a shiny speck because the sun glinted off Curiosity at just the right angle as NASA's Mars Reconnaissance Orbiter swooped overhead.SEE ALSO: The secretive lab that built 'the bomb' now scours Mars for signs of lifeNASA plans for the nuclear-powered machine to inch up Mt. Sharp over the coming years to investigate the landscape and improve our understanding of what the now-desert terrain was like billions of years ago, when the Martian planet was a wetter, bluer place. In 2020, a more advanced car-sized rover will join Curiosity on the Martian ground. The new rover will scour the Jezero Crater, a 30 mile-wide bowl about 1,640 feet deep. It's believed to have once held an 800-foot deep lake some 3.5 billion years ago. WATCH: Meet Katie Bouman, one of the scientists who helped capture the first black hole image