æt fˈɜːst, ðɪ ˈɑːpʃən ʌv vˌɪlɐfɹˈæŋkə dˈɛl kæstˈiːoʊ mədɹˈɪd wʌz kənsˈɪdɚd, wˌɛɹ ˌiːˌɛsˈeɪ ɔːlɹˌɛdi hɐz ɐ spˈeɪs ɐstɹˈɑːnəmi sˈɛntɚ ˈɛsæk, bˌʌt ɪt wʌz dɪskˈɑːɹdᵻd dˈuː tʊ ɪts ɐksˈɛlɚɹˌeɪɾᵻd ˈɜːbən dɪvˈɛləpmənt, wˈɪtʃ wʊdhɐv bˌɪn, wɪðˌaʊt ɐ dˈaʊt, ɐ sˈeɪf sˈoːɹs ʌv ˌɪntəfˈɪɹəns.
At first, the option of Villafranca del Castillo (Madrid) was considered, where ESA already has a Space Astronomy Center (ESAC), but it was discarded due to its accelerated urban development, which would have been, without a doubt, a safe source of interference.