PASADENA, CA—After initial transmissions from the Mars rover Curiosity provided multiple images of the Red Planet, officials from NASA's Jet Propulsion Laboratory confirmed Monday that scientists are now pretty sure the surface of Mars is rocky. "There are still a lot more tests to conduct, and many additional research projects that will take quite some time to complete, but we are now more certain than ever that Mars is covered in rocks, and that those rocks are red in color," said JPL director Charles Elachi, explaining that Curiosity had already transmitted several high-resolution photographs of "a whole bunch of rocks" from its landing spot in Mars' Gale Crater. "We are only one day into our two-year expedition, but we feel confident in our hypothesis that the surface of Mars contains many kinds rocks—not just ordinary-sized rocks, but perhaps also very large ones. I would say we’ll need to send several more rovers up there, and eventually a manned mission, to prove once and for all that Mars has rocks on it." Elachi also told reporters that he is optimistic the $2.5-billion mission will be a stepping stone toward one day concluding that Mars is big, cold, and completely uninhabitable.