Julie Payette urged Canadians and global citizens to reach for their dreams and join forces to tackle the pressing problems of climate change, migration and poverty as she was installed as Canada's 29th Governor General today.

Surrounded by family, dignitaries, fellow astronauts and past and present politicians in a ceremony inside the packed Senate chamber, the former astronaut said we're all on the "same planetary spaceship" and stressed a collective duty to close the gap in inequities around the world.

"I'm a true believer in the strength of teamwork, in the power of dreams and in the absolute necessity of a support structure," she said, speaking without notes.

"Anyone can accomplish anything and rise to the challenge as long as they are willing to work with others, to let go of the personal agenda, to reach a higher goal and to do what is right for the common good. This is exactly what I hope my mandate as the governor general will reflect."

Julie Payette approaches the steps of Parliament as she walks to attend her installation ceremony Monday. (Sean Kilpatrick/The Canadian Press)

Recalling how her parents and family gave her unwavering support in following her childhood dream of becoming a space explorer, Payette stressed the importance of accessible education, promoting diversity and the pursuit of sport.

"There is no magical solution other than working hard and moving forward," she said.

Payette also spoke directly to Indigenous leaders and other guests in the chamber, praising their generosity and courage through history. She said Indigenous people taught us how to survive the cold and appreciate the gifts of nature.

Gov.-Gen. Julie Payette says her mandate is "to do what is right for the common good," adding that anything can be accomplished as long as people are willing to work with others. 0:51

"It is a good thing that we finally decided again to listen to their wisdom," she said.

'Exceptional Canadian'

Rideau Hall described it as a "momentous day" in a formal itinerary outlining the day's events. Payette, 53, swore the oaths of allegiance before a 21-gun salute outside.

Prime Minister Justin Trudeau described Payette as a team player, trailblazer and pioneer who inspired the minds, dreams and imaginations of children and adults alike. He called her an "exceptional Canadian" who is both an accomplished scientist and compassionate citizen.

From astronaut to Governor General: Julie Payette journeyed to space twice, but her next mission at Rideau Hall is expected to come with its own kind of challenges. 2:57

"Your journey to space and through life may be unique, but the qualities that underpin each and every one of your successes are not," he said. "Your numerous achievements are, above all. a testament to your hard work, discipline, and most importantly your passion.

"Whether as Canada's chief astronaut or as an Olympic flag bearer, you represent the very best of what it means to be Canadian and to serve Canada with aplomb and integrity."

Trudeau also paid tribute to outgoing governor general David Johnston, praising him for seven years at Rideau Hall building a "stronger and better Canada."

Former Governor General David Johnston salutes as guests in the Senate chamber applaud his tenure in the position during the installation ceremony for Canada's 29th Governor General, Julie Payette, in Ottawa on Monday, Oct. 2, 2017. (Adrian Wyld/Canadian Press)

Johnston received a standing ovation in the packed Senate chamber.

Payette was accompanied by Heritage Minister Mélanie Joly and greeted by Trudeau, Senate Speaker George Furey, House Speaker Geoff Regan and Indigenous elders.

She was led by the Usher of the Black Rod Greg Peters through the Hall of Honour and into the Red Chamber.

Payette, who had invited Canadians to take part in the historic day in a tweet posted on the account she has assumed from outgoing Gov. Gen. David Johnston, said she wished all Canadians could join her in the room.

Dear Canadians, friends from around the world: experience this installation day with me, as I begin my mandate as Governor General. —@GGJuliePayette

Payette personally chose the music played during the ceremony, including Fanfare of the Common Man, a piece by American composer Aaron Copland, which was played as the wake-up music of at least two shuttle crews.

Canada's 29th Governor General Julie Payette looks on from her seat as Prime Minister Justin Trudeau bows to her before his speech in the Senate chamber during her installation ceremony, in Ottawa on Monday, Oct. 2, 2017. (Adrian Wyld/Canadian Press)

Last year, Payette tweeted that the first three notes of the Montreal Metro were the same as the song, which has been featured in several films and other creative productions.

400 personal guests of Payette

Payette was accompanied by her parents, siblings and her 14-year-old son Laurier for the morning's events. She said her son was her first adviser, and that he gave her permission to accept the governor general's job.

She personally invited about 400 guests, according to a briefing from federal officials.

The Senate chamber holds around 750 people, but guests spilled into an overflow room.

Gov.-Gen. Julie Payette says it is our collective responsibility to make Canada and the world a better place, "because global issues know no borders." 1:31

All former governors general, past prime ministers and sitting premiers were invited. Adrienne Clarkson and Jean Chrétien have arrived, while Michaëlle Jean, John Turner and Kim Campbell had sent their regrets. Stephen Harper tweeted his congratulations Monday morning.

"I hope she has a very interesting time and I believe she will do a wonderful job," said Clarkson, describing Payette as a "terrific" person.

Payette is wearing clothes by Marie Saint Pierre, a Montreal-based Canadian fashion designer, and wearing the Companion of the Order of Canada insignia and her lapel pin of l'Ordre national du Québec.

She is also wearing the Last Spike Brooch, a diamond brooch made from one of the last two spikes in the tracks to complete the Canadian Pacific Railroad in Craigellachie, B.C. in 1885.

The brooch has traditionally been worn by female governors general or spouses of male governors general, on installation day and when reading speeches from the throne.

After a series of artistic and cultural performances, Payette walked to the National War Memorial, where she laid flowers in honour of those who died in past conflicts.

An evening reception at the Canadian Museum of History will cap off the day's events.