MONTREAL -- He may never be known as Flash Garneau, but the latest contender for the helm of the federal Liberals hopes his astronaut credentials will give him a lift.

Marc Garneau repeatedly played up his resume as Canada's first man in space as he officially launched his leadership campaign Wednesday.

The Montreal MP touted himself as the Liberals' best hope for defeating Prime Minister Stephen Harper, having gained the necessary experience and leadership skills during an impressive career before jumping into the political arena in 2008.

"I want to be the prime minister of Canada, I want to be the Liberal leader," Garneau told a news conference in Ottawa shortly after formally kicking off his campaign in his Montreal riding.

"I will talk about my strengths and my strengths are proven ... There will be no modesty here. I'm going to speak specifically about what I've done in the Navy, what I've done in the space program, including being the president of the Canadian Space Agency."

Garneau insisted he's not daunted by the prospect of going up against fellow Montreal MP Justin Trudeau, son of former prime minister Pierre Trudeau and the prohibitive favourite.

"When I sent in my application (to become an astronaut), I was one of 4,000 people and I ended up No. 1," Garneau said. "So, I like to take on challenges and I'm taking on this challenge and I intend to win."

His campaign kickoff was starkly different than Justin Trudeau's launch early last month and the contrast suggests Garneau has plenty of work to do to catch up to the front-runner, both in terms of campaign organization and personal appeal.

Garneau strode into a packed hotel meeting room in his Montreal riding early Wednesday to a standing ovation from some 100 people. The event, however, featured no big-name Liberals, no music, only a few chants of "Garneau, Garneau, Garneau."

Having said repeatedly he wouldn't enter the race unless he was certain he could put together an effective campaign team, Garneau curiously refused Wednesday to name members of his team, other than campaign director Andy Mitchell, a former Ontario MP and cabinet minister.

His launch was significantly more reserved than Trudeau's rally in another part of the city last month. Trudeau received a rock-star welcome when he made his announcement before a boisterous, adoring throng of 500 supporters. The crowd included a number of former MPs, at least one current MP and some of his father's former cabinet ministers.

A number of sitting MPs have since jumped on Trudeau's bandwagon.

Garneau shrugged off questions as to why no MPs are supporting him thus far, suggesting Liberals are waiting to compare all the candidates during five leadership debates in the new year. After that, he said they'll cast their votes on April 14 with only one question in mind: "Who is the best candidate to defeat Stephen Harper?"

"That is the fundamental question and I believe that I am this person," he said.

On his way into the weekly Liberal caucus meeting in Ottawa, Trudeau welcomed Garneau's entry into the race.

"He's a man of ideas and strength and he is going to be an important player in the coming months in the rebuilding of the Liberal party," Trudeau said. "And I'm very excited he's part of it."

Trudeau has long been seen by his critics -- some of them fellow Liberals -- as a man of more flash than substance.

Garneau, meanwhile, is well-regarded on Parliament Hill as an earnest, hard-working, intelligent MP. He is known as a soft-spoken politician who rarely displays hyper-partisan bombast often expected of political leaders.

On several occasions during his speech Wednesday, Garneau appeared to force himself to make an extra effort to raise his voice to a booming level.

"Join me today and together we will take Canada to new heights," he shouted into the microphone in closing out his address.

He also took repeated pot shots at the Harper government, although he misfired in one instance.

"Today, under Harper, we have an angry, we have a divisive, we have an intolerant Canada. We have an intolerant government," he asserted.

Garneau later said he "misspoke" when he said Canada was intolerant, that he meant only the Tory government and corrected himself immediately.

His speech touched on issues such as streamlining taxes to make them fair for everyone, ensuring Canadians can enjoy a secure retirement, and generating more jobs inside and outside the natural-resources sector.

He told the crowd that it's time for Canada to put more focus on developing knowledge-based sectors, rather than relying too much on volatile natural resources.

"Under Stephen Harper, we've returned almost to our colonial past -- we are the hewers of wood and the drawers of water," he said, underlining the need to build on existing industries such as biotechnology, aerospace and video-game development.

"Believe me, this is isn't rocket science. I know something about rocket science and this is not about rocket science."

He also urged the Liberal party, reduced to a shadow of its once-mighty self in the 2011 election, to embrace change.

"We must build on the past, but not live in it," he said.

"We don't have a natural entitlement to be the government of this country -- we have to earn it from Canadians and we are going to earn it from Canadians."

Garneau rejected a proposal by rival contender Joyce Murray, to allow local Liberals, New Democrats and Greens to join forces behind a single candidate to defeat the Tories in some ridings. If he becomes leader, he said the Liberals will run candidates in all 338 ridings across the country.

He also showed his intention to reconnect with Quebec, which was once fertile ground for Liberal support. In last year's election, voters steered their support en masse to the NDP, electing them in 59 of Quebec's 75 seats.

Garneau said Quebecers are fed up with old constitutional battles and promised to help the province realize its potential.

The former naval engineer was defeated in his first run for office in 2006, but he was elected in the longtime Liberal stronghold of Westmount-Ville-Marie in 2008. He was re-elected in 2011.

Garneau stepped aside as Liberal House leader on Wednesday and was replaced by Dominic LeBlanc.

Garneau, a Quebec City native, became the first Canadian to fly in space, when he served as a payload specialist aboard the Challenger shuttle in October 1984.

He flew on a total of three shuttle missions, logging over 677 hours in space. Garneau then served as president of the Canadian Space Agency from 2001 to 2005 before jumping into politics.

Supporter Laurent Debrun, who attended Wednesday's launch, believes Garneau's wealth of experience positions him as the best candidate to unite Canadians, and eventually unseat the Conservatives.

"I think people will realize that over the next four months," said Debrun, who lives in Garneau's riding and plans to help him raise money for his campaign.

Campaign volunteer Louise Jarrold said she was impressed by Garneau's resume, including his background as an engineer and his time as head of the Canadian Space Agency.

"I like people who have done something substantive in their life and have a proven track record -- you can't get much more substantive than Mr. Garneau," the college psychology professor said.

When asked about Trudeau, Jarrold said she thinks he still has work to do.

"He seems like a hard worker and I'm sure that over the years he will accomplish things, but you know, he's riding on the coattails of his father," she said of Trudeau, before dismissing criticism that Garneau doesn't have enough charisma to lead.

"Is Mr. Harper flashy? ... I don't think Canadians are that much into flash it would seem from the votes in the past."

Garneau joins a large field of contestants, which includes Trudeau, Vancouver MP Murray, former Toronto MP Martha Hall Findlay, Ottawa lawyer David Bertschi, Toronto lawyer Deborah Coyne, retired Canadian Forces Lt.-Col. Karen McCrimmon, Vancouver prosecutor Alex Burton and David Merner, former president of the party's B.C. wing.

Toronto lawyer George Takach is expected to join the race on Thursday. Ontario government economist Jonathan Mousley is still hoping to enter if he can raise the stiff $75,000 entry fee.

So far, only Trudeau and Coyne have officially registered as candidates, filed the required nomination papers and paid the first of three $25,000 instalments on the entry fee. Garneau said he has also paid the fee and filed his papers but the party has not yet processed his application.