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North American Aviation (NAA) was the prime contractor for the Apollo Command and Service Module (CSM). In December 1965, the company’s engineers briefed NASA’s Office of Manned Space Flight (OMSF) and Bellcomm, OMSF’s planning contractor, on results of a preliminary feasibility study of a one-man CSM mission to rescue Apollo astronauts stranded in lunar orbit.
The NAA engineers did not describe specific lunar-orbit rescue scenarios, though the CSM modifications they outlined offer clues about the types of rescues they envisioned. The normal CSM docking unit was an active probe system that could dock only with a passive drogue system. The Apollo Lunar Excursion Module (LEM) moon lander carried the drogue system. (The LEM was later called the Lunar Module, which was abbreviated LM and pronounced “lem.”) The special docking unit on the rescue CSM’s nose would be configurable as either an active probe or active drogue, so could be used to dock with either a LEM or a passive CSM. The rescue CSM pilot could reconfigure the docking unit in flight, implying that the situation in lunar orbit might be unknown or in flux when he departed Earth. The rescue CSM would also carry a dish-shaped LEM docking radar on an extendible boom to facilitate rendezvous and docking with a disabled CSM.
NAA expected that a lunar-orbit rescue might require a spacewalk, so provided the rescue CSM pilot with a tether and a