Mars was the fourth planet from the Sun and the second smallest planet in the Solar System, after Mercury. Named after the Roman god of war, it was often described as the "Red Planet" because the iron oxide prevalent on its surface gave it a reddish appearance. Mars was a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts, and polar ice caps of Earth. The rotational period and seasonal cycles of Mars were likewise similar to those of Earth, as was the tilt that produces the seasons. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Martian trojan asteroid.
After the discovery of Robotechnology, Mars became one of the first sites chosen to build the off-world colony, Base Sara. The site was abandoned during the Global War, due to acts of terrorism, and then later was destroyed completed during the First Robotech War. The planet has since then become an off-world outpost for the United Earth Forces well until the end of the Second Robotech War. The planet has since been repurposed into a Staging Ground and rearming depot for returning Robotech Expeditionary Forces from deep space, in preparation for the coming Invid Invasion.