Sometimes referred to as the ?Red Planet? due to its iron oxide rich soil, which gives it red appearance, Mars is a terrestrial planet (consisting primarily of silicate rocks) with a thin atmosphere and slightly more than half the size of Earth. Since the Mariner and Viking missions in the 60s and 70s a multitude of spacecraft have reached and explored Mars including orbiters, landers and rovers. Evidence collected by these unmanned missions suggest that large parts of the Red Planet once were covered with water and that there still are large quantities of water ice on both its poles and at mid-latitudes. These discoveries have reignited the idea that at some point in its history Mars could have sustained life and restarted discussions about manned missions and eventual colonization of the planet. Learn more about the our red neighbor and mankind's past, present and future attempts at its exploration in this book.