 The mission was originally planned as Apollo 9, to be performed in early 1969 as the second test of the complete Apollo spacecraft, including the Lunar Module and the Command / Service Module in an elliptical medium Earth orbit. But when the Lunar Module proved unready to make its first test in a lower Earth orbit in December 1968, it was decided in August to fly Apollo 8 in December as a more ambitious lunar orbital flight without the Lunar Module. This meant Borman's crew was scheduled to fly two to three months sooner than originally planned, leaving them a shorter time for training and preparation, thus placing more demands than usual on their time and discipline.
