The International Space Station (ISS) is dangerous and unfit for purpose, Russia's space chief said on Thursday, as Moscow pushes ahead with plans to quit the project and launch its own station.
Yuri Borisov, head of the Roscosmos agency, said mass equipment failures and ageing parts were endangering crew safety on the 24-year-old station.
The ISS had been a rare area of cooperation between the United States and Russia even as diplomatic ties worsened.
But since Russia invaded Ukraine in February and subjected to a barrage of Western sanctions, it has become more intent on leaving and launching its own space station sometime after 2024.
"Technically, the ISS has exceeded all its warranty periods. This is dangerous," Borisov said. "An avalanche-like process of equipment failure is beginning, cracks are appearing."
He said Russia's station would orbit Earth around the poles, enabling it to look down on far more of Russia's vast territory and gather new data on cosmic radiation.
The ISS was launched in 1998 and has been occupied continuously since November 2000 under an American/Russian-led partnership that also includes Canada, Japan and 11 European countries. The U.S. space agency NASA wants to keep it functioning until 2030.
Last month, Borisov unveiled a model of Russia's planned station, which he said on Thursday would be open to cooperation with "friendly countries".
Borisov, a former deputy prime minister with a defence background, said Western sanctions on Russia's space industry had ruined the prospects for further cooperation.
He singled out the European Space Agency's decision to terminate cooperation with Russia on the ExoMars rover, which is due to hunt for life on Mars by the end of the decade.
"An enormous amount of effort and huge sums of money were spent on that ... but politics intervened, and what is the result? It shouldn't be like this, it's wrong," Borisov said.
Moscow is now eyeing China and other "friendly countries" to cooperate with.
In particular, Borisov said Russia was "looking at how to interact with our closest colleagues, first of all China", to pool efforts to explore the moon and deep space.