Astronauts on Mars, artwork. Humans will require protection to explore the surface of Mars because the thin atmosphere is nearly all carbon dioxide. Surface temperatures range from -89 to -31 degrees Celsius. Mars has no surface water and is a rocky desert world. The surface area is the same size as Earth's land surface area. The thin crescent moons in the sky are the two satellites of Mars, Deimos (upper left) and Phobos (upper right). The female astronaut (foreground) represents the UK, and the male astronaut (background) represents France in a four-country joint mission that includes Germany and Japan.