Who: Marc Garneau, Liberal MP for Montreal's Westmount-Ville-Marie riding.
Age: 63 (Feb. 23, 1949)
Personal: Born in Quebec City. Married to Patricia Soame. Father of four children.
Education: Earned bachelor of science degree in engineering physics from Royal Military College in Kingston, Ont., and doctorate in electrical engineering at England's Imperial College of Science and Technology.
Early career: Served as Navy officer. Was named one of Canada's original six astronauts, and in 1984 became first Canadian to fly in space. Served as president of Canadian Space Agency from 2001 to 2005.
Politics: Defeated in Vaudreuil-Soulanges as Liberal candidate in 2006. First elected in Westmount-Ville-Marie in 2008 and re-elected in 2011. Was Liberal House leader from June 2011 until Wednesday.
Quote: "Yes, I was an astronaut, but I don't want to be defined by what I did up there. I want to be defined by who I am inside, here."