[5] From 1935 to 1946, Lacroute was an astronomer at the Toulouse Observatory where he set up an astrophysics department specializing in spectroscopic observation of stars.
[7] Since its creation in 1972 with the support of Jean Delhaye, then director of the National Institute of Astronomy and Geophysics, the observatory has housed the Centre de Données astronomiques de Strasbourg (Strasbourg Astronomical Data Center), world database of astronomical knowledge.
In 1967, Pierre Lacroute proposed to the Centre national d'études spatiales (CNES, National Centre for Space Studies), to equip an artificial satellite with a telescope in order to obtain a star catalogue more accurate than could be established using terrestrial telescopes.
[10] The CNES agreed to develop the project but in view of its cost decided to move towards multinational financing.
After a feasibility study carried out in 1977, the European Space Agency finally agreed in 1980 to finance the mission.