The event, which will include Canada's newest astronauts David Saint-Jacques and Jeremy Hansen, along with retired astronaut Chris Hadfield, takes place at 12:15 p.m. ET at the Canada Aviation and Space Museum in Ottawa.
It's expected to be the official announcement of Canada's contribution to the operation of the International Space Station until 2024. That funding was first disclosed in the federal budget in April.
"This commitment will ensure that both Jeremy Hansen and David Saint-Jacques, Canada's two active astronauts, will both fly to space," a senior government source told CBC News. "It also signals Canada's involvement in future space missions to the moon, Mars and beyond."
Under a bartering system, countries collect "credits" based on their contributions to the development of the space station, with the credits traded in for trips by astronauts.
Canada used up most of them for Chris Hadfield's five-month visit in 2013, when he served as the first Canadian commander of the space station.
Saint-Jacques and Hansen were named as Canada's new astronauts in 2009. They have been training ever since, but neither has ever flown in space.
The U.S. and Russia have also committed to funding the space station until 2024. But the space station's other key partners, the European Space Agency and JAXA, the Japan Aerospace Exploration Agency, have not yet committed themselves beyond 2020.