Apollo8 was planned as the "D" mission, a test of the LM in a low Earth orbit in December 1968 by James McDivitt, David Scott, and Russell Schweickart, while Borman's crew would fly the "E" mission, a more rigorous LM test in an elliptical medium Earth orbit as Apollo9, in early 1969.
ɐpˈɑːloʊ ˈeɪt wʌz plˈænd æz ðə "dˈiː" mˈɪʃən, ɐ tˈɛst ʌvðɪ ˌɛlˈɛm ɪn ɐ lˈoʊ ˈɜːθ ˈɔːɹbɪt ɪn dᵻsˈɛmbɚ nˈaɪntiːnhˈʌndɹɪd sˈɪksti ˈeɪt baɪ dʒˈeɪmz mək dˈɪvɪt, dˈeɪvɪd skˈɑːt, ænd ɹˈʌsəl ʃwˈeɪkɑːɹt, wˌaɪl bˈoːɹmənz kɹˈuː wʊd flˈaɪ ðə "ˈiː" mˈɪʃən, ɐ mˈoːɹ ɹˈɪɡɚɹəs ˌɛlˈɛm tˈɛst ɪn ɐn ɪlˈɪptɪkəl mˈiːdiəm ˈɜːθ ˈɔːɹbɪt æz ɐpˈɑːloʊ nˈaɪn, ɪn ˈɜːli nˈaɪntiːnhˈʌndɹɪd sˈɪksti nˈaɪn.