If the crew had not burned the engine, or the burn had not lasted the planned length of time, the crew would have appeared early from behind the Moon.
ɪf ðə kɹˈuː hæd nˌɑːt bˈɜːnd ðɪ ˈɛndʒɪn, ɔːɹ ðə bˈɜːn hæd nˌɑːt lˈæstᵻd ðə plˈænd lˈɛŋθ ʌv tˈaɪm, ðə kɹˈuː wʊdhɐv ɐpˈɪɹd ˈɜːli fɹʌm bᵻhˌaɪnd ðə mˈuːn.