"In the Universal Century timeline, space colonies are placed at five gravitationally stable points in space, known as Lagrangian points. In most cases, a Lagrangian Point is home to more than one group of space colonies. A group of colonies that occupy a Lagrangian Point are known collectively as a "Side". Because Sides sometimes share a single Lagrangian Point, it is possible to have two Sides in close orbit to one another. All colonies in the Universal Century are O'Neill "Island 3" type colony cylinders.

The first 50 years of the Universal Century were spent building the various colonies and placing them in the Lagrangian Points, as well as colonizing the moon. By U.C. 0050 9 billion of the 11 billion people in the Earth Federation live in space colonies or on the moon. In U.C. 0051 the Federation froze plans for additional colony development, and in U.C. 0084 reorganized the remaining Sides into different Lagrangian Points. With the re-organization of the Sides completed, the Federation announced that the status quo would be maintained. In the latter half of the Second Universal Century the construction of new colonies was restarted."