The invasion of Ukraine threatens to end the long-standing relations between the US and Russia in space through the International Space Station.

A multinational collaborative project, the International Space Station is a massive space habitat built on the collaboration of five space agencies, including US’ NASA and Russia’s national space agency Roscosmos. It is divided into two sections -- the Russian Orbital Segment and the US Orbital Segment. At present, there are four astronauts from NASA, one from Europe and two Russian cosmonauts living and working onboard the orbiting outpost.

After US President Joe Biden imposed sanctions on Russia for its military operation in Ukraine, the head of Russia's space agency took to Twitter to denounce the constraints, saying it would "destroy" the teamwork between the two countries on the ISS.

"If you block cooperation with us, then who is going to save the ISS from an uncontrolled descent from orbit and then falling onto the territory of the United States or Europe?" Roscosmos director general Dmitry Rogozin tweeted, adding that a 500-tonne structure could fall in India or China as well.

“Do you want to threaten them with this prospect?” Rogozin tweeted.

Responding to Rogozin's outburst, NASA said it would continue collaborative work with all of its international partners, including Roscosmos, "for the ongoing safe operations of the International Space Station", Reuters reported.

The Russian segment is powered by electricity on the American side, while the American section depends on propulsion systems on the Russian side, former NASA astronaut Garrett Reisman told CNN. "So, you can't do an amicable divorce. You can't do a conscious uncoupling," Reisman said.

Despite confrontations on land, the ISS has served as a steady beacon of hope for international collaboration between the two superpowers for decades. The charmed life of the ISS program has overcome all sorts of political and technical issues, CNBC quoted Voyager Space president Jeff Manber as saying.

NASA and Roscosmos continued to collaborate on the ISS even after Russia’s invasion of Crimea in 2014. NASA had then sent a memo to its employees asking them to suspend contact with Russian government representatives and restrict travelling to Russia. Dmitry Rogozin, who was then deputy prime minister, was personally sanctioned from entering the US.

Although Manber does not think the Ukraine crisis will jeopardise the partnership, he pointed out that the Russian space agency Roscosmos has not yet renewed its role beyond 2024 while the US was prepared to extend operations to 2030.

Earlier there were reports of NASA administrator Bill Nelson visiting Russia to discuss ISS operations. However, no such trip is currently planned, NASA press secretary Jackie McGuinness told The Verge.

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(Edited by : Thomas Abraham)