Water-ice clouds, polar ice, polar regions, and geological features can be seen in this full-disk image of Mars. Mars is a cold desert world. It is half the diameter of Earth and has the same amount of dry land. Like Earth, Mars has seasons, polar ice caps, volcanoes, canyons and weather, but its atmosphere is too thin for liquid water to exist for long on the surface. There are signs of ancient floods on Mars, but evidence for water now exists mainly in icy soil and thin clouds. Featured Mission: Mars Science Laboratory/Curiosity Curiosity, a robotic rover about the size of a small SUV, is designed to find whether the Red Planet ever was -- or is still today -- an environment suitable for life. The rover landed on Mars in August 2012. Read More About Mars  305

Just the Facts Metric | English | Scientific Notation Orbit Size (semi-major axis):  227,943,824 km Mean Radius:  3,389.5 km Volume:  163,115,609,799 km3 Mass:  641,693,000,000,000,000,000,000 kg More Facts  Resources Missions to Mars Images of Mars Videos about Mars Power to Explore: Radioisotope Power Mars Exploration (Jet Propulsion Laboratory) Power to Explore: Radioisotope Power Curiosity Rover Landing Toolkit On Mars: Early Exploration of the Red Planet (1958-1978) What Time is it on Mars? (JAVA Application) Mars Exploration: Is There Water on Mars? (materials for teachers) Exploring the Planets - Mars Mars Classroom The Great Mars Debate NASA Mars Lithograph NASA Planetary Photojournal - Mars Mars: NASA Explores the Red Planet Compare Mars to other Planets/Moons More Resources  Calendar 19 Jan 2013:  Mars Science Laboratory/Curiosity: AIAA Educator Academy -- San Antonio (9 a.m. - 5 p.m.) 23 Feb 2013:  Mars Science Laboratory/Curiosity: AIAA Educator Academy -- Phoenix (8:00 a.m. - 5 p.m.) Sep 2014:  MAVEN: Mars Orbit Insertion Oct 2016:  ExoMars/Trace Gas Orbiter: Mars Orbit Insertion Oct 2016:  ExoMars/Trace Gas Orbiter: ExoMars Demonstration Landing