At the behest of the Nixon administration to add a reference to God, NASA included the vague date as a reason to include A.D., which stands for Anno Domini ("in the year of our Lord").
æt ðə bᵻhˈɛst ʌvðə nˈɪksən ɐdmˌɪnɪstɹˈeɪʃən tʊ ˈæd ɐ ɹˈɛfɹəns tə ɡˈɑːd, nˈæsɐ ɪŋklˈuːdᵻd ðə vˈeɪɡ dˈeɪt æz ɐ ɹˈiːzən tʊ ɪŋklˈuːd ˈeɪ.dˈiː., wˌɪtʃ stˈændz fɔːɹ ˈænoʊ dəmˈiːni"ɪnðə jˈɪɹ ʌv ˌaʊɚ lˈɔːɹd".