Star Dragon
The American Union's colonization of other worlds starts with leaving earth. During the initial colonization rush this was achieved using the first Star Dragon lifters. These massive, amphibious, rockets carried some of the first starship-grade fusion reactors which were far too large for smaller reusable rockets. The design was sold, improved, and refurbished over the centuries but the fundamental design remained the same.
Though launches from earth have become more rare as space infrastructure has continued to develop, the Star Dragon is still a vital component of getting into space throughout the Human Sphere.