When first proposed in 1959, the spacecraft that would eventually become known as the Apollo Command and Service Module (CSM) was envisioned as a three-man Earth-orbital vehicle upgradable to lunar-orbital capability. On November 15, 1960, NASA awarded six-month feasibility study contracts for just such an Apollo spacecraft to the Martin Company, the Convair Division of General Dynamics, and the General Electric (GE) Company Defense Electronic Division, Missile and Space Vehicle Department. The CSM at that time was to include a Command Module (CM), a Service Module (SM), and an orbital module, a kind of mini-space station. The three companies submitted their final study reports on May 15, 1961.
Ten days later, President John F. Kennedy redirected Apollo – and, indeed, the entire U.S. civilian space program – toward the goal of landing a man on the moon by the end of the 1960s. On November 28, 1961, NASA awarded North American Aviation (NAA) the contract to build the Apollo CSM, the initial design of which included two modules: the conical CM and the drum-shaped SM. At the time, the method by which NASA would carry out the President’s mandate remained uncertain, though it was widely assumed that it would soon award a contract for a third Apollo spacecraft module: a landing propulsion module for lowering the CSM to the lunar surface. NAA went so far as to design the Service Propulsion System (SPS) main engine, mounted at the base of the SM, with enough thrust to launch the CSM off the