In 2020 the major spacefaring companies came together with NASA to form the Mars Corporation, an US Government sponsored conglomerate aimed at the permanent human colonization of Mars. With the collapse of Russia, many former Union State scientists joined the project as well, defecting to their former enemy. The Mars Corporation, as an entity tied to the US Government, could not legally accept non-US Citizens as colonists for fear of technology theft, and as such was limited to an entirely domestic labor pool, which was already overburdened by the population crisis. These purely American companies then proceeded to divide the planet Mars into administrative possessions that would become the colonies, with each colony or territory being tied directly to one of the Mars Corporation's member organizations. NASA could not legally claim ownership to any territory in accordance with the 1967 Outer Space Treaty, but private companies were still free to administer these regions without ceding them directly to the United States. The largest possessions were claimed by SpaceX and Lunar Energy Ltd. (LE), the two largest contributors to the project at the time outside of NASA.
The Mars Corporation organizing with its member organizations, launched the first manned mission to Mars in 2023, organized primarily through NASA as a purely scientific mission. Landing in Terra Meridani, and establishing Meridian Base, Expedition 1, while successful in discovering conclusive proof of ancient life on Mars, largely confined to the seas and rivers, was unable to establish a base that could permanently house colonists without aid from Earth. This was not a terrible setback, as the first privately launched mission by LE. established the first successful base in what is now the city of Bradbury in the Tharsis Territory. NASA, initially hesitant to be tied down by private companies seeking to exploit Mars beyond scientific interest, revised their relationship with the Mars Corporation so that NASA scientists would simply be stationed at MarsCorp bases. Shortly after the success at Bradbury, SpaceX founded the city of Opportunity at the landing site of the famous rover. Much like Bradbury, Opportunity was a domed settlement, constructed entirely from onsite materials to shield the inhabitants from the planet's deadly radiation. Inside the dome a stable habitat could be formed to provide for its occupants. Over the next five years the first colonies were established all over Mars, with smaller research stations and largely unmanned industrial and resource extraction sites. A problem quickly arose in this rapid settlement as food production in many of the cities could not keep up with the nutritional demands of the colonists, save for those in the Tharsis Territory, where LE, the most established off world corporation prior to Mars, focused its efforts away from an immediate return on its investments to instead develop lasting food supplies. With many smaller problems revealing themselves on an almost daily basis, MarsCorp was partially reorganized for more cooperation between the colonies, with the construction of the New Richmond Space Elevator, and the Mars Transit network between the Tharsis and Argyre colonies.
During this time, the colonies had successfully begun the most ambitious of MarsCorp's projects: The Terraforming Program. From the first touchdown at Bradbury, the colonies began spreading a cocktail of genetically modified organisms (GMOs) across the planet via disposable drones. These organisms, little more than bacteria, spread across the planet's surface processing the toxic dust into a usable soil base and extracting greenhouse gasses from the soil. When a given condition of these organisms would be met (O3 levels rising to a certain point, the selenium content of the soil, etc.) a fail-safe in their genome would trigger their demise, depositing more vitamins into the new soil base. Meanwhile orbital mirrors, constructed out of next generation nanoprinters on the moon, were deployed to heat up the surface of the planet. Additionally, the new space elevator allowed asteroid mining firms from Earth via their new Martian colonies to set out for the Asteroid belt and begin peppering Mars with asteroids to generate more heat, and by 2036, even expand the size of Mars's moons by moving several large asteroids to Martian orbit. From this continuous addition of heat and a thicker atmosphere to hold it all in, Mars rapidly developed oceans over the course of the next two decades. The red planet now had a foundation from which to develop a biosphere, and while it would take decades, Mars was now on its way to habitability.
By 2050 Mars's oceans had expanded to cover the northern lowlands of the planet. River beds were dredged, and canals carved via orbital mirror to provide water to the interior. Genetically tailored algae, lichens, fungi, and simple mosses and ferns were added to the planet during the 2040s to build the all important topsoil from the now slightly less toxic dust. By the middle of the 50s the grasses, ferns, clovers, and mosses were being added where the soil base is strongest, and in some cases the shrubs and trees were being given a trial run. The first insects were to arrive shortly thereafter, while the seas were being pumped full of a host of genetically tailored corals and plankton to take advantage of the iron rich seawater. Surface temperatures at the equator hovered around 25 degrees C during the long summer, increased incrementally with the regular nitrogen shipments from Titan. The atmosphere was just dense enough at this point to allow settlers to exit the protective domes without full pressure suits. For Mars WWIII wasn't just a distant event that they could not realistically participate in, as it was for the outer colonies. The emotional weight of the war was still felt, as colonists had old friends and family who fought and died to preserve their safety and freedom from the endless conflicts of Earth.