In 1957 the Department of Defense (DoD) released a set of requirements for a new heavy-lift booster for missions starting in the early 1960s. At the time, all three branches of the US military were in the process of developing their own rockets, which led to considerable in-fighting between them on the priority of future developments. In 1956 the US Air Force won the concession that long range rocketry was its domain, including all ground-to-ground missiles over range. The agreement did not cover "other roles" however, and existing projects at the Navy and Army continued as before.