"We are not a closed club, our doors are wide open," Vladimir Popovkin, the head of the Russian Space agency, said after a meeting Thursday of the leaders of the organizations involved in the station.
Popovkin ventured that the day will come when China and India will work together with the five ISS partners — Canada, the United States, Russia, Japan and the European Space Agency.
Jean-Jacques Dordain, head of the European body, said he hopes the International Space Station partnership would be open, adding it would benefit from co-operation with China.
"I am in favour of seeing how we can work together with China," he told reporters after the meeting in Quebec City. "It will take some steps, but it will come, I am sure.
"This is not a closed partnership, it is an open partnership and anyone who can help support this partnership is more than welcome."
Dordain noted it took almost 40 years to bring together and build the current partnership.
"It will take some time for China to join us and it will take some time to have India, South Korea, Brazil," he added.
NASA administrator Charles Bolden pointed out that the five partners are reaching out to other non-traditional nations.
"We have encouraged each other to go out and try to find people who would not have an opportunity to enjoy this incredible facility that we have and bring them in as best we can," he said.
Bolden has told The Canadian Press that NASA is an organization that looks at international co-operation, but it's prohibited by Congressional action from any bilateral activities with China.
But he adds that he hopes the space partners will continue their conversations with the Chinese — and if a relationship does develop, it's a peaceful one.
During their meeting, the five space agency heads discussed opportunities to use the station "as a foundation for the development of future exploration capabilities."
Bolden said it would be premature to talk about its life being extended beyond 2020, but added that, from an engineering standpoint, it can probably last until 2028.
It was only as the space agency bosses were preparing to sit down to discuss the future use of the station that Canada finally announced it would commit itself to the lab until 2020.
Industry Minister Christian Paradis announced Wednesday that Canada will extend its commitment to the ISS from 2015 to 2020.
The Canadian Space Agency played host to Thursday's get-together and president Steve MacLean called it "an impressive meeting."
He said now that the assembly of the space station is complete, the next step is to start using it as a world-class laboratory.
"We as a partnership will continue to shift the focus to the great work that we can do that will benefit mankind," he said.
MacLean added that the ISS group is focused on how the station can be used as a stepping stone to the next phase of space exploration.
"That makes it quite exciting to imagine what the station will do for the future," he added.