Former astronaut Marc Garneau confirmed on Sunday that Liberal Leader Stephane Dion's ambivalence was one of the main reasons he announced his departure from politics earlier this week.

Widely considered as a star candidate in Quebec, Garneau said during an interview on CTV's Question Period that Dion's refusal to endorse two nomination bids -- one in Westmount-Ville Marie in May and the other in the riding of Outremont last January -- was a major decision for his political departure.

Garneau resigned as head of the Canadian Space Agency in 2005 to run unsuccessfully for the Quebec Liberals in the 2006 federal election in the riding of Vaudreuil-Soulanges.

"You get very excited about politics. It's something that is almost a little bit addictive. I put in a lot of time during 2006 and I gave up a job in 2005 to run and I really did enjoy the time that I was involved with it," Garneau said Sunday.

"But the reality is that we have to get on with our lives too."

Garneau said Dion didn't contact him after he made the announcement earlier this week but said he didn't expect a call from the leader urging him to stay in politics.

"Sometimes between two people, it just doesn't work out and I'm not necessarily part of somebody's vision," Garneau said.

There has been speculation Dion is punishing Garneau for his support of Micheal Ignatieff's 2006 Liberal leadership bid.

Garneau said he expressed his interest in running again last January during a conversation with Dion, after former Outremont Liberal MP Jean Lapierre quit politics. He said he was told by the leader at that time that the riding was reserved for another candidate.

Last May, Garneau filed nomination papers when Liberal MP Lucienne Robillard announced she would not run again in the riding of Westmount-Ville Marie. Dion announced less than a week later that he had hand-picked someone else to run in the riding, further discouraging Garneau.

He made the decision to leave public life after his family summer holidays, citing a need to provide financially for his family as one of the reasons for his departure.

"I decided that well, since I don't know what the future holds for me its time for me to get back into private life," Garneau said.

Watchful eyes on Dion

Garneau said he will remain a "very committed Liberal" and will closely follow Dion's reaction to government's throne speech on Oct. 16. The embattled Dion has suffered several blows recently, including losses in three Quebec byelections and the withdrawal of Garneau and other key candidates.

"Dion, by his own admission, has work to do. He has come out and said very clearly that it's not sufficient to pass the messages, to have policies, to have ideas, to have vision," Garneau said.

Dion confidante and Liberal MP Bryon Wilfert told QP on Sunday that he will advise Dion against triggering an election when the throne speech is delivered, citing a lack of party preparation and no clear defining election issues to rally behind.

"We're never afraid of fight, but I think when you go into a fight you should pick the timing," Wilfert said.

"I don't see any rush. I believe that obviously there are issues with regard to money and organization," Wilfert said referring to organizational issues in the federal Liberal party.

Dion has maintained he will need to hear Prime Minister Stephen Harper's response to four key issues before deciding how to vote after the Oct. 16 speech.