Complex sentence: In the distant future, Mankind has colonized space (with clusters of space colonies at each of the five Earth-Moon Lagrange points), and, down on the Earth, the nations have united as the United Earth Sphere Alliance.
Split into simpler sentences: In the distant future, Mankind has colonized space, with clusters of space colonies at each of the five Earth-Moon Lagrange points. Down on the Earth, the nations have come together to form the United Earth Sphere Alliance.