Year 20XX. The planet Earth, with the pass of time, was running out of resources, and space for humans to live. The solution they got, from decades and centuries in the past, was explore beyond the planet, to answer their questions... "What is outside?", " Is there any other types of life?", "What other planets have to offer?", and much more questions in their mind, being wondered by their selves, as they try to give answers.
From the year 2094, humanity developed spaceships to travel in the cold void of space, as they had to leave their planet, to continue surviving...
Passed months, and even years, after they started travelling within the stars, and studying much efficiently the planets.
They already had information of other planets in the galaxy, as Mars, Jupiter, and other planets in the Solar System, as they named it. Their knowledge was still low, as for what exactly was in each planet, but their ambitious was such, they couldn't stop until dominate with their expansion all the galaxy, and what could be beyond... Deeper in the cold void of space...
Decades after start living in the spaceships, they already had stations for supplies, to can maintain their selves. There were dozens of stations, built in the space, by different groups of humans, from dozens different spaceships. Humanity was covering much of what they got to know of their galaxy, and the Solar System, and develop instruments and artifacts to can create artificial life and oxygen more efficiently in inhabitable planets.
Is unknown what other planets humanity colonized, but we know... Mars was one they took...