The manned Venus flyby that could have happened

That would have been neat. [Link]

The crew would launch on a Saturn V during a month-long window beginning on October 31 and ending on November 30, 1973. This window offered the best geometry for a quick transit to Venus and the year was chosen because it was expected to be one with minimal solar activity — a good thing to take advantage of since the crew would be going towards the sun. At their closest, the crew would be only 0.7 AU from the Sun. (1 AU is the distance from the Earth to the Sun, about 93 million miles or 150 million kilometres. 0.7 AU is about 65.1 million miles or 105 million kilometres.)

After a brief stay in Earth orbit, the crew would fire their SIV-B stage (the upper stage of the Saturn V) and begin their transit to Venus. The outbound leg of the trip would last 123 days, making the crew’s arrival at Venus some time around March 3, 1974. Like Mariner 2, they would flyby rather than go into orbit, giving them only a brief time for up close observations and experiments. After their brief encounter with the planet, the spacecraft would sling around and begin its 273 day trip back to Earth. The crew would arrive and splash down, just like they would on Apollo, around December 1, 1974. Including the month-long launch window, the mission was planned for 400 days.