The Saturn project was started as one of a number of proposals to meet a new Department of Defense (DoD) requirement for a heavy-lift vehicle to orbit a new class of communications and "other" satellites. The requirements called for a vehicle capable of putting into orbit, or accelerating to trans-lunar injection. Existing U.S. launchers could place a maximum of about in orbit, but might be expanded to as much as with new high-energy upper stages. In any event, these upper stages would not be available until 1961 at the earliest, and would still not meet the DoD requirements for heavy loads.