Hellas Planitia, often called Hellas or Hades, is an industrial center and the largest Martian city, and was the site for some humanity’s earliest sustained settlements on Mars.
History
Although further away and in a different sector to Earth during the Khan Solar Storm, the regolith covering of the early outposts such as Jezero Crater was not sufficient to prevent the first explorers from receiving a lifetime radiation dose over the course of several hours. In 173 BFC a consortium of companies and the United States government began detailed imagining of the lava tubes at the northern rim of Hellas Basin, and later that year the Dao Vallis Outpost was established in the largest tube system. The deepest tubes were excavated for the living quarters, and featured polyethylene water tank lined walls to further reduce the radiation risk. Early infrastructure was characterized by electrolysis-based oxygen generation, heavily algae-based food systems along with limited hydroponics, the development of metal-sequestering microbes, and significant challenges posed by perchlorate contamination in Martian soil and ice and prolonged dust storms sometimes limiting the available power to the outpost's small fission reactors.
Initially the site of robotic underground farms supplementing the Dao Vallis Outpost food supply, the Orcus Colony on the floor of the basin began to house colonists once advancements such as better pykrete and biopolymer bound regolith bricks (along with the thicker atmosphere on the basin floor) reduced the radiation risk sufficiently. The first of the iconic diamond triangle graphene domes was erected here for above ground farming and light for the colonists. Water for the colony was initially obtained from the basins ice deposits until the later convoy system of polar crawlers was established. Orcus University was the first tertiary education established on Mars, and was responsible for developing the Martian lichen which famously absorbs water from the air and uses it to excretes desiccation-proof insulating materials. The colony was also the site of the first large scale MarsNet deployment, and was heavily affected by the Stillborn Harvest terrorist attack.
Due to the higher atmospheric pressure the basin became the largest fuel manufacturing center on Mars, and the early Martian creole culture can be seen in some recorded interactions between colonists with crew from this time. The later mining of rare earth elements cemented its position as the largest industrial center on Mars, by which time the colony filled the entire basin and became officially known as Hellas Planitia.