It suffices to mention that,
as noted above, Manuel started being interested in the role played
by varying effective gravities in fluid physics. This led himto accept consultancy
with the European Space Agency (ESA) for about a decade. He
was member of the ESA-Microgravity Advisory Committee (ESA-MAC)
and various other ESA specialist panels. Later on Manuel became the
president of the European Low Gravity Research Association (ELGRA).
During this period he was appointed, with a five-year contract, CNRS
Visiting professor with the University of Provence (Aix-Marseille). His
action, in close collaboration with Etienne Guyon led to a spectacular research
development. In 1994 the University of Aix-Marseille awarded
Manuel an Honorary Doctorate.