Mars is the fourth planet from the Sun in the Solar System. Named after the Roman god of war, Mars, it is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance. Mars is a terrestrial planet currently being terraformed by humanity for permanent colonization; and at present is home to some 30 million human colonists, not including those living in orbital colonies. Mars is the first planet humanity has terraformed, and the lessons learned have contributed to similar action on Venus.
Almost immediately following the end of the War, humanity began studying the potential for terraforming Mars through reversed engineered Ch'rix technology, as well as human inventions. It was quickly found that with the advancements in technology made through the knowledge gained from the Ch'rix, Mars could be feasibly terraformed relatively easily, and within a single human lifetime. Long term habitability would be considerably more difficult, as Mars's moons do not provide enough tidal force to keep the planet's weak magnetosphere powerful enough to sustain a robust atmosphere.
Terraforming began in earnest in 2025 with the Department of Space Exploration and Colonization's (DSEC) de-orbiting of several asteroids and comets to heat up the planet and thereby cause polar melting to thicken the atmosphere. Construction also began on the Surface of several artificial volcanoes, while 4 Pollux and 2 Vesta underwent a process that would allow them to be towed into Martian orbit to provide larger moons. The combination of these events would give Mars a more robust magnetosphere over time, and make the human terraforming efforts permanent.
While the atmosphere thickened from the melting of the polar caps, several species of GMO bacteria, algae, and fungi were spread across the planet's surface to convert the toxic CO2 atmosphere into breathable oxygen while providing the basis for an ecosystem.
As of 2080 Mars has a fully breathable atmosphere and semi-stable biosphere, marked by relatively small areas of sustainable biodiversity, but not yet planet-wide sustainable ecosystems. The planet's magnetosphere, while growing stronger with the help of an expanded Phobos and Demos and artificial Volcano network, is still too weak to significantly hinder solar flare radiation.
After the controlled collision of the original Martian moons, Phobos and Deimos have expanded to a point of being large enough to initiate appropriate tidal forces on the surface of Mars. The Asteroids also feature several bases for processing fuel for spacecraft, as well as providing communications services.