The Apollo Applications Program (AAP) was created as early as 1966 by NASA headquarters to develop science-based human spaceflight missions using hardware developed for the Apollo program. AAP was the ultimate development of a number of official and unofficial Apollo follow-on projects studied at various NASA labs. However, the AAP's ambitious initial plans became an early casualty when the Johnson Administration declined to support it adequately, partly in order to implement its Great Society set of domestic programs while remaining within a $100 billion budget. Thus, Fiscal Year 1967 ultimately allocated $80 million to the AAP, compared to NASA's preliminary estimates of $450 million necessary to fund a full-scale AAP program for that year, with over $1 billion being required for FY 1968. The AAP eventually led to Skylab, which absorbed much of what had been developed under Apollo Applications. Origins NASA management was concerned about losing the 400,000 workers involved in Apollo after landing on the Moon in 1969. A reason Wernher von Braun, head of NASA's Marshall Space Flight Center during the 1960s, advocated for a smaller station after his large one was not built was that he wished to provide his employees with work beyond developing the Saturn rockets, which would be completed relatively early during Project Apollo. NASA set up the Apollo Logistic Support System Office, originally intended to study various ways to modify the Apollo hardware for scientific missions. Initially the AAP office was an offshoot of the Apollo "X" bureau, also known as the Apollo Extension Series. AES was developing technology concepts for mission proposals based on the Saturn IB and Saturn V boosters. These included a crewed lunar base, an Earth-orbiting space station, the so-called Grand Tour of the Outer Solar System, and the original Voyager program of Mars Lander probes. AES (Apollo Extension Series) Lunar Base The Apollo lunar base proposal saw an uncrewed Saturn V used to land a shelter based on the Apollo Command/Service Module (CSM) on the Moon. A second Saturn V would carry a three-person crew and a modified CSM and Apollo Lunar Module (LM) to the Moon. The two-person excursion team would have a surface stay time of nearly 200 days and use of an advanced lunar rover and a lunar flier as well as logistics vehicles to construct a larger shelter. The isolation of the CSM pilot was a concern for mission planners, so proposals that