23. Apollo 1 Was Supposed to Be Called AS-204
NASA started the mission on 27 January 1967 and was set on naming it AS-204. However, the families of the departed astronauts asked to have it renamed Apollo 1. While this is a tragic way to begin a mission to space, NASA learned a lot from their mistakes.
In between this failed mission and the next manned mission, NASA tested several ground-controlled spacecraft into space, testing and making sure their astronauts were safe.