Frank was the commander of the mission that sent him and his crew to loop around the moon and return to earth. It was a very bold and risky undertaking as it was the first-time humans had ridden the Saturn V launch vehicle, which on its previous unmanned flight was plagued with problems. It was decided to attempt this because the Lunar Module was late being delivered, and the program needed impetus to keep it on schedule. If they had waited for the lunar module to be flight ready there would have been a gap of five months between flights, as it was Apollo 8 launched two months after Apollo 7.