ɪt kˈeɪm ˌɪntʊ ˌɑːpɚɹˈeɪʃən ˌɔn θˈɜːtiːn sɛptˈɛmbɚ nˈaɪntiːnhˈʌndɹɪd sˈɪksti wˈʌn tə səpˈoːɹt ðə mˈɜːkjʊɹiˈætləs fˈoːɹ tˈɛst flˈaɪt, ænd kəntˈɪnjuːd tə tˈeɪk pˈɑːɹt ɪn mˈɜːkjʊɹi mˈɪʃənz, ɪŋklˈuːdɪŋ dʒˈɑːn ɡlˈɛnz mˈɜːkjʊɹiˈætləs sˈɪks ˈɜːθ ˈɔːɹbɪt.
It came into operation on 13 September 1961 to support the Mercury-Atlas 4 test flight, and continued to take part in Mercury missions, including John Glenn’s Mercury-Atlas 6 Earth orbit.