Can private-sector space business be profitable, or is it just an exciting way for billionaires to live out their fantasies?

The Martian has been praised as the rare science fiction movie that takes pains with scientific accuracy, but one of the more prosaic events in the movie is actually among the least likely.

In the film, Chinese and US space agencies work together to save the day. But in fact, that kind of international Kumbaya moment is forbidden by US law—a restriction underscored today (Oct. 13) at the International Astronautical Congress (IAC).

The chief designer of China’s space program, Zhou Jianping, said his country would solicit international partners for a space station it plans to launch in 2022, with opportunities ranging from shared experiments and spacecraft visits by foreign crews to building permanent modules to attach to the main station.

The European and Russian space agencies already have signed preliminary agreements with China, but NASA will have to snub the project.

The ban on cooperation between NASA and the China Manned Space Program is a legacy of conservative lawmaker Frank Wolf, who cut off any funding for work with China in protest of political repression there and for fear of sharing advanced technology; he retired in January, but the restrictions remain in place.

And NASA is not a fan of them.

In his own remarks at the IAC, NASA administrator Charles Bolden said the US, for its own good, ought to dump the four-year-old ban.

“We will find ourselves on the outside looking in, because everybody…who has any hope of a human spaceflight program…will go to whoever will fly their people,” Bolden said, according to a report from Reuters.

Currently, China operates a space station called Tiangong 1 that has hosted several multi-week visits by groups of Chinese astronauts. The US supports the International Space Station and its permanent crew of three to six astronauts alongside 15 other countries, including Russia. Both the US and Russia have committed to provide support to the station through 2024.

NASA Russian cosmonaut Alexey Leonov and US astronaut Tom Stafford hang out in space in 1975.

The US has a long history of space diplomacy with opponents—as with the USSR during the 1970s. With US policy framing China as a peaceful competitor rather than ideological enemy, the current restrictions on consorting with the Chinese space program has put NASA in a tough spot with space scientists from outside the agency, some of whom have protested the ban by boycotting scientific conferences.

If the desire for manned cooperation with the Chinese is not enough to persuade US lawmakers to loosen their restrictions, there’s also the increasing concerns among space agencies and satellite operators that a lack of coordination between burgeoning space programs will lead to potential orbital disaster. Tests of anti-satellite weapons have already resulted in costly, in-orbit accidents.

Civil space cooperation between the US and China could provide trust and lines of communication for de-escalation as fears of space militarization increase. And it’s not like there isn’t some cross-pollination already—SpaceNews notes that Zhou received some of his training at the University of Southern California.