Manned Venus Flyby

A number of proposals for a manned Venus flyby have been considered since the start of the space age.

NASA considered a manned fly-by of Venus in the mid-1960s as part of the Apollo Applications Program, using hardware derived from the Apollo program. Launch would have taken place on October 31, 1973, with a Venus flyby on March 3, 1974 and return to Earth on December 1, 1974.

The proposed mission would use a Saturn V to send three men to fly past Venus in a flight which would last approximately one year. The S-IVB stage would be a 'wet workshop' similar to the original design of Skylab. In this concept, the interior of the fuel tanks would be filled with living quarters and various equipment that did not take up a significant amount of volume. The S-IVB would then be filled with fuel as normal and used to accelerate the craft on its way to Venus. Once the burn was complete, any remaining fuel was vented to space, and then the tank could be used as living space.

Only so much equipment could be carried in the hydrogen tank without taking up too much room, while other pieces could not be immersed in liquid hydrogen and survive. These sorts of systems would instead be placed in the interstage area between the S-IVB and the Apollo Command/Service Module (CSM), known as the Spacecraft-LM Adapter (SLA), which normally held the Apollo Lunar Module on lunar missions. To maximize the amount of space available in this area, the Service Propulsion System engine of the CSM would be replaced by two LM Descent Propulsion System engines. These had much smaller engine bells, and would lie within the Service Module instead of extending out the end into the SLA area. This also provided redundancy in the case of a single-engine failure. These engines were responsible for both course correction during the flight as well as the braking burn for Earth re-entry.

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