Apollo Applications Program
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The Apollo Applications Program (AAP) was established by NASA headquarters in 1968 to develop science-based manned space missions using surplus material from the Apollo Lunar Landing Program. AAP was the ultimate development of a number of official and unofficial Apollo follow-on projects studied at various NASA labs.
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[edit] Origins
Initially the AAP office in Washington was an off-shoot 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 manned 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.
The Apollo lunar base proposal saw an unmanned 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 man crew and a modified CSM and Apollo Lunar Module (LM) to the moon. The two man 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 it would be a three man landing team or that the CSM would rendezvous with an orbiting module were considered.
To support longer stays on the Moon, NASA also studied a number of simple Lunar Escape Systems as a means of returning two astronauts from the lunar surface to an orbiting CSM if the Lunar Module ascent stage engine failed to ignite.
Another plan for Apollo-based extended duration manned spaceflight would use a Saturn V to send three men on a Manned Venus Flyby, using the Saturn S-IVB stage as a 'wet workshop'. First the S-IVB would boost itself and the Apollo CSM on a trajectory that would pass by Venus and return to Earth, then any remaining fuel would be vented to space, after which the astronauts would live in the empty fuel tanks until they separated from the S-IVB shortly before re-entry on their return to Earth.
[edit] Development
When procurement of Saturn Vs other than those required for the lunar landing was stopped in 1968 focus shifted to AAP. Aside from attempting to show that Apollo presented value for money, NASA and the main contractors of Boeing, Grumman, North American Aviation and Rockwell also hoped to put-off the inevitable scaling down of staff and facilities following the completion of the first moon landing.
Three AAP proposals were selected for development:
The Apollo Telescope Mission would be an earth orbiting mission for solar observation. The telescope would be based on a modified Lunar Module ascent stage, and launched using a S-IVB. The telescope would be docked to a CSM with a three man crew. Solar panels on the telescope would provide additional power, allowing an extended mission of 21-28 days. The telescope module would include a pressurized compartment providing additional living and workspace for the crew.
The Apollo Manned Survey Mission proposed an Earth-observation science module also based on the LM ascent stage, and would also have been launched using a S-IVB vehicle into a high inclination orbit. It was also proposed that a surplus Saturn V would launch a manned lunar survey mission to establish suitable sites for later manned landings.
The wet workshop concept provided for a low-budget earth orbiting space station. The original plan, as proposed by Werner von Braun, used the S-II stage as the primary structure of the station, with the area normally filled by the S-IVB stage replaced with an equipment carrier. These plans were modified to use the S-IVB when Saturn V production ended with just enough boosters for the lunar missions alone.
In the meantime several of the Earth-orbit "checkout" missions for Apollo had been canceled, leaving a number of Saturn IB's unused. The plans were changed to use the S-IV stage, used on both rockets, as the primary station structure. A modified S-IVB would be launched into orbit, the second stage carrying a docking module and large solar panels in the area normally carrying the LM. A CSM would then be able to dock with the second stage and enter the now-empty fuel tanks. It was also suggested that the Apollo Telescope and Survey Mission modules might be docked to the Wet Workshop to create a modular space station.
[edit] Skylab
Originally AAP missions would alternate with Apollo lunar missions starting in 1969. However when NASA's 1969 budget was cut, focus was shifted to the Skylab space station proposal, which managed to accommodate the equipment already specified for some of the AAP missions. Specifically, Skylab included the Apollo Telescope Mission (renamed the Apollo Telescope Mount) attached to the docking station used by the CSMs. Since the Saturn V stack placed the S-IVB in orbit without it needing to fire on its own, the extra lift capacity of the stage was not needed and it could be launched "dry". This allowed the interior space to be better "fitted out," although many design concepts from the Wet Workshop, notably the open flooring that allowed fuel to flow through it, were kept in Skylab.
The concept of launching one of the 'Spare' unused Skylabs into lunar orbit was briefly discussed around the same time, but no justification could be found for it, so the project was abandoned early on.
