UEPF

The UEPF is the force of spaceships that stands above Terra Nova, and is supposed to make sure that nukes are not used on the ground. They did this in Terra Novas equivalent of the world wars by nuking the 2 of the FSC's cities when they nuked Yammato's cities. In practice at least by the book A Desert called Peace they work with the terrorists and progressive forces to stop the FSC from having as much control as they do. The FSC hates the UEPF, and Earth is afraid that when they get space travel they will go to earth and destroy their class system and rule over them.

They travel from Earth to Terra Nova through a rift in space, that allows instantaneous travel from one point to the next. The fleet itself is in extremely bad repair, becuase Earth either will not or cannot give them the required materials to keep it in working shape.