This change was less than the planned , because of a bubble of helium in the oxidizer lines, which caused unexpectedly low propellant pressure.
ðɪs tʃˈeɪndʒ wʌz lˈɛs ðɐn ðə plˈænd , bɪkˈʌz əvə bˈʌbəl ʌv hˈiːliəm ɪnðɪ ˈɑːksɪdˌaɪzɚ lˈaɪnz, wˌɪtʃ kˈɔːzd ˌʌnɛkspˈɛktᵻdli lˈoʊ pɹəpˈɛlənt pɹˈɛʃɚ.