During the initial human expansion from Earth, chimpanzees were uplifted for use in the space programs that required fairly complex tasks, beyond the brain of a baseline chimpanzee, to be performed, but had an unacceptably high failure/fatality rate for a human crew. Due to their similarities to their older cousins, chimpanzees are the most accepted uplift genome in modern society and mix freely with the human populations of the outer settlements like Saturn.