[1] Favier was the advisor to the director of the Material Science Research Center (CEREM) at the French Atomic Energy Commission (CEA) and was detached to CNES.

He was the principal investigator for a MEPHISTO materials processing experiment, which made its debut on the United States Microgravity Payload in 1992 and 1994.

Favier was assigned as an alternate payload specialist on STS-65/IML-2, the second International Microgravity Laboratory mission, and supported the mission as a Crew Interface Coordinator (CIC/APS) from the Payload Operations Control Center (POCC) at the Marshall Space Flight Center in Huntsville, Alabama.

STS-78 orbited the Earth 271 times, covering 7 million miles in 405 hours, 48 minutes.

Favier was a member of the board of advisors of the International Space University and also the chair of the research steering committee.