|There is more information available on this subject at Mars on the English-language Wikipedia.|
The exact history of Mars prior to 2075 is largely unknown. It is known that as early as the 2000s, a company called the Ultor Corporation may have had plans to start a mining operation on the planet.
A shortage of usable minerals on Earth gave Ultor the perfect opportunity to create mining colonies on Mars without any interference, regulation, or oversight.
By 2075, the Ultor Corporation had established a large number of mining camps on the planet. It was in these camps that Ultor brutally forced miners to work under extremely poor conditions; an Ultor employee known as Dr. Capek also performed nanotechnology experimentation (known as "the Plague") upon miners -- without their consent, and with no provisions taken to ensure their well-being.
In 2078, a miner-led rebellion called the Red Faction fought back. Led by Eos and assisted by Parker, the miners managed to kill Capek, cure the Plague, and create an opportunity for the Earth Defense Force (EDF) to liberate the planet.
During the next fifty years, the EDF restructured the Ultor Corporation. Terra forming of Mars took place, and the planet was reorganized into sectors. Two sectors, Parker and Eos, were named after the greatest heroes of the miner rebellion.
Though they originally came to Mars in order to free the miners, the EDF eventually become tyrannical, taking complete control over the planet, ruling it with an iron fist, and suppressing all dissent. They used their control over the media to constantly air propaganda.
Meanwhile, a mysterious and very violent group of people called the Marauders would form tribal settlements on Mars. They may have descended from the Mutants, part of Capek's legacy. It is also believed they are the descendants of the Ultor Corporation, upon the EDF storming the facility many of the science team hid in the mines, fearful of the EDF. As EDF go room to room gunning people down in the complex, these people fear for their lives and cut off all contact. It is believed the Marauders are the children of those people.
Red Faction: Guerrilla
By 2120, Mars had changed drastically. At least one fairly large area of the planet -- Tharsis -- had been terraformed, albeit unevenly -- some sectors, such as Parker, were less terraformed than others.
A small group of people banded together to revive the Red Faction, with a new goal of defeating the EDF and once again liberating Mars. Led by Hugo Davies and assisted by Dan Mason, Samanya, and Alec Mason, the Red Faction eventually liberated Tharsis one sector at a time, starting with Parker.
The planet's polar icecaps have led some scientists to believe that Mars may have had water; however, others speculate that water cannot exist on the surface due to lack of atmospheric pressure. Many scientists believe it is possible to terraform Mars. The atmosphere of the planet is made of 95% carbon dioxide.
Terraforming mars would be possible, though the planet has a very low average surface temperature. The entire temperature of the planet would have to be raised by several degrees for any plant life to exist.