The criteria for what constitutes human spaceflight vary, with some focus on the point where the atmosphere becomes so thin that centrifugal force, rather than aerodynamic force, carries a significant portion of the weight of the flight object.
ðə kɹaɪtˈiəɹɪə fɔːɹ wʌt kˈɑːnstɪtˌuːts hjˈuːmən spˈeɪsflaɪt vˈɛɹi, wɪð sˌʌm fˈoʊkəs ɔnðə pˈɔɪnt wˌɛɹ ðɪ ˈætməsfˌɪɹ bɪkˌʌmz sˌoʊ θˈɪn ðæt sˌɛntɹɪfjˈuːɡəl fˈoːɹs, ɹˈæðɚ ðɐn ˌɛɹoʊdaɪnˈæmɪk fˈoːɹs, kˈæɹiz ɐ sɪɡnˈɪfɪkənt pˈoːɹʃən ʌvðə wˈeɪt ʌvðə flˈaɪt ˈɑːbdʒɛkt.