Hadfield is scheduled to return to Earth on Monday after a five-month visit to the International Space Station.
During the latter stages of his stay, he became the first Canadian to command the orbiting space laboratory.
Gilles Leclerc, interim head of the Canadian Space Agency, says there probably won't be another Canadian travelling to the station for at least three more years.
"Right now, Canada doesn't have a slot for an astronaut on the launch manifest of NASA before 2016," he said in an interview.
A NASA spokesman said in an email the last international crew to be confirmed will launch in December 2014.
Leclerc noted that Canada collects "credits" based on its contributions to the development of the space station, with the credits traded in for trips by astronauts.
"The ISS is a big co-operative," he said. "You get in return what you put into the program and right now we still have some credits left, but we have to accumulate these credits."
Leclerc added it will be "between 2016 and 2019" that the next Canadian astronaut will travel to the space station.
That trip would go to one of Canada's two rookie astronauts: David Saint-Jacques or Jeremy Hansen.
In the meantime, the future of the entire Canadian space program is on hold as the Harper government reviews the recommendations of a report on the sector.
The report was part of a broad review of the aerospace industry commissioned by the Conservative government.
Former cabinet minister David Emerson, who headed the review, was blunt when he issued his report last November.
He said the Canadian space program had ''floundered'' over the last decade.
"There's been some lack of clarity around priorities and uneven performance in the implementation of projects,'' Emerson said at the time.
Leclerc told The Canadian Press he expects the future direction of the space agency to be decided in the coming months, adding it is involved in preparing a response to the report.
He said much will also depend on Canada's four space partners: NASA; the European Space Agency; JAXA, the Japan Aerospace Exploration Agency; and Roscosmos, the Russian space agency.
"The ultimate objective for all space agencies is to send a human to Mars and, in the interim, there are various missions and destinations, we're looking at," Leclerc said.
NASA is currently studying a plan to send humans to an asteroid in 2025.
Leclerc noted that a precursor to that mission is OSIRIS-REx, a 2016 sample return mission to a primitive asteroid, which uses a vision system provided by Canada.
"We're still at the stage with our international partners where we're studying what could be the next destination," he added.
Chuck Black, treasurer of the Canadian Space Commerce Association, doesn't see anything happening at the Canadian Space Agency before August or September, when he expects a new permanent president to be appointed.
"That'll be the first indication how things are going to move forward," he said in an interview from Toronto.
Former president Steve MacLean stepped down in February — months before his term was to expire in August 2013.
With Hadfield returning to Earth on Monday, Black volunteered he didn't expect the space veteran to become the next president.
"Chris Hadfield and Steve MacLean and all the other astronauts are very tight, very close together," Black said.
"Hadfield is going to remember what happened to Steve MacLean and he's going to govern himself accordingly."
Black's organization is an industry group that represents about 40 small and large space companies in Canada.
He said Canadian firms have not been sitting around waiting for the Harper government to help them out.
In recent years, he noted, the Canadian space program has been moving away from the public sector toward private partnerships.
Black said Canadian companies such as MacDonald, Dettwiler and Associates (TSX;MDA), which builds robotic space arms, are manufacturing their components for Americans and Europeans.
He pointed to MDA's recent purchase of Space Systems/Lorel, a U.S. spacecraft manufacturer. It's described as one of the "big five" in commercial satellite construction.
"Quite frankly MDA has enough money to do what it wants, it's going to have direct access to American markets," Black said.
"There are a lot of options, but most of these options are not travelling through the Canadian Space Agency."
While he is "tremendously optimistic" about the Emerson report, Black's prediction is that the CSA will assume a smaller and smaller role over the years.
He said it would probably continue to focus on the space station, which will continue to operate until at least 2020.Suggest a correction