SAp has always been very open to the outside, welcoming researchers from other institutes. For this reason, very close links have existed between SAp and CNRS since the mid-70s.
The structure of this collaboration has, for a long time, been an associated research unit (URA 2052). In 2001, the decision was made to convert the URA to a transitional research federation (FRE2591), a 2-year temporary structure enabling the unit to evolve to a new structure, namely a mixed research unit (UMR).
Since 1997, DAPNIA’s Astrophysics Service has been associated with Paris-7 University through the γG team. This mixed team (four research academics and four physicists from the CEA in 1997) had expanded to six research academics and 13 physicists from the CEA at the time of the 2001 four-year plan.