 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 . 
