The oldest person to reach orbit is John Glenn, one of the Mercury 7, who was 77 when he flew on STS-95.
ðɪ ˈoʊldɪst pˈɜːsən tə ɹˈiːtʃ ˈɔːɹbɪt ɪz dʒˈɑːn ɡlˈɛn, wˈʌn ʌvðə mˈɜːkjʊɹi sˈɛvən, hˌuː wʌz sˈɛvənti sˈɛvən wɛn hiː flˈuː ˌɔn ˌɛstˌiːˈɛs nˈaɪnti fˈaɪv.