NASA Curiosity rover completes 2,000 days on Mars
NASA's nuclear-powered Mars Curiosity rover has completed 2,000 Martian days on the Red Planet. Called "sol", a Martian day lasts 40 minutes longer than a day on Earth. Curiosity landed in 2012 and has travelled 18.7 km since then. The $2.5-billion mission has found evidence of an ancient freshwater-lake environment on Mars that offered all chemical ingredients for microbial life.