hiː bɪɡˈæn hɪz pɹəfˈɛʃənəl kɚɹˈɪɹ æt ðə sˈɛntɚ nˈæʃənəl dˈɛɾuːdz spˈeɪʃɪˌeɪlz sˈiːnˈɛs ɪn fɹˈæns, ænd fɹʌm nˈaɪntiːnhˈʌndɹɪd sˈɛvənti tˈuː tə nˈaɪntiːnhˈʌndɹɪd ˈeɪɾi tˈuː wʌz səksˈɛsɪvli hˈɛd ʌvðɪ ˈɔːɹbɪt dɪtˌɜːmᵻnˈeɪʃən ænd spˈeɪskɹæft daɪnˈæmɪks dᵻpˈɑːɹtmənt, ðə saɪəntˈɪfɪk pɹˈoʊɡɹæmz dᵻvˈɪʒən ænd ðɪ ˌæplɪkˈeɪʃən pɹˈoʊɡɹæmz dᵻvˈɪʒən.
He began his professional career at the Centre National d'Etudes Spatiales (CNES) in France, and from 1972 to 1982 was successively Head of the Orbit Determination and Spacecraft Dynamics Department, the Scientific Programmes Division and the Application Programmes Division.