The above manuals describe the configuration of the Apollo command module (mother ship) environment control system and space suit. The date of the manuals is 1966. The term BLOCK II indicated the series of command modules which were configured for flights to the Moon. The BLOCK I vehicles were to operate in Earth orbit to test features which would be used in flights to the Moon. Unfortunately, the destruction of the first manned BLOCK I vehicle, SPACECRAFT 012, during a launch pad test in January of 1967 terminated plans to launch a manned BLOCK I configuration into orbit.