dᵻspˈaɪt ðoʊz tʃˈælɪndʒᵻz ðə ɹˈiːzənz fɔːɹ ðɪs dᵻsˈɪʒən ɑːɹ: ðə lˈɔs ʌv mˈɑːɹz ɡlˈoʊbəl sɚvˈeɪɚɹ ɪn tˈuː θˈaʊzənd sˈɪks, ðə poʊstpˈoʊnmənt ʌvðə mˈɑːɹz tˈuː θˈaʊzənd twˈɛnti tˈuː ˈɔːɹbɪɾɚɹ æz ðə pɹəpˈoʊzd səksˈɛsɚɹ ʌv ˌɛmˌɑːɹɹˈoʊ ænd mˈævən ˈɛs ʃˈɔːɹɾɪdʒ ʌv fjˈuːəl, ðæt mˌeɪks ˌɛmˌɑːɹɹˈoʊ nˈaʊ ðə kɹˈɪɾɪkəl ˈɛlɪmənt ʌvðə nˈæsɐ fˈɜːðɚ mˈɑːɹz ɛksploːɹˈeɪʃən pɹˈoʊɡɹæm.
Despite those challenges the reasons for this decision are: the loss of Mars Global Surveyor in 2006, the postponement of the Mars 2022 orbiter as the proposed successor of MRO and MAVEN'''s shortage of fuel, that makes MRO now the critical element of the NASA's further Mars Exploration Program.