Jean-Jacques Dordain, director general of the European Space Agency, said that while the ISS has been a "splendid success," it was being severely hampered by the chaotic approach to planning missions to and from it, The Daily Telegraph reported Wednesday.
Starting in July, Russia will be the only country with a system that can carry astronauts to and from the station, due to the phase-out of the U.S. space shuttle program.
"The biggest lesson from the international space station program is entirely the lack of a joint transportation policy," he said. "The International Space Station is a splendid co-operation between five partners, but they did make a mistake ... we didn't discuss things sufficiently."
Citing the U.S. decision on shuttle flights, Dordain said "unilateral decisions" on transportation policy by participating countries, while justified on "individual grounds," did not consider the wider context of other nations' capabilities, leading to a situation of "anarchy."
The European Automated Transfer Vehicle and Japanese H-II Transfer Vehicle, along with the veteran Russian Progress freighter, are one-way craft that burn up in the atmosphere after delivering their cargo loads to the ISS.
That leaves the Russian Soyuz system as the only method of transporting astronauts to and from the station, but the capsule is incapable of carrying large non-human cargo such as large equipment for experiments.
"We are not in a very comfortable situation, and that's just a euphemism," Dordain said.