Russia has threatened to stop its collaboration with the West on the International Space Station (ISS) program once again.

Dmitry Rogozin, the head of Russia's state space agency Roscosmos, has condemned the sanctions placed on his country by the U.S., Japan, Canada, and the European Union - the other ISS partners - for its invasion of Ukraine.

"I believe that the restoration of normal relations between partners in the International Space Station and other joint projects is possible only with the complete and unconditional lifting of illegal sanctions," Rogozin said via Twitter on Saturday (April 2). (He tweeted in Russian; translation provided by Google.).

On Mar.14, Rogozin reportedly addressed this or a similar complaint in a formal manner to the ISS partner agencies; on Saturday, he posted on Twitter what he claimed were some partners' responses to a letter from that day.

Rogozin, for example, posted what he claimed was a letter from NASA Administrator Bill Nelson dated Mar. 30.

"The U.S. continues to support international government space cooperation, especially those activities associated with operating the ISS with Russia, Canada, Europe, and Japan," Nelson's letter states, in part. "New and existing U.S. export control measures continue to allow cooperation between the U.S. and Russia to ensure continued safe operations of the ISS."

Rogozin's latest tweets do not necessarily imply that the ISS program is in imminent jeopardy; the Russian space chief is a loud personality with a history of making exaggerated claims.

On the day Russia invaded Ukraine, for example, Rogozin stated that newly implemented economic sanctions could "destroy" the ISS partnership. But, since then, it's been more or less business as usual aboard the orbiting lab. NASA astronaut Mark Vande Hei, for example, returned to Earth on March 30 on a Russian Soyuz spacecraft with two cosmonauts. Despite the increased global tensions, the landing went off without a hitch.

Due to deteriorating relations in other space projects including Russian participation, Rogozin has been making a lot of blustery statements on Twitter recently.

Rogozin, on the other hand, is well-known in the space community for producing contentious content. A series of tweets in response to Biden's sanctions, for example, suggested that people in charge of executing them might be "suffering from Alzheimer's disease."

On Mar. 3, Rogozin banned the sale of Russian engines to the U.S., saying, "Let them fly on something else, on broomsticks."

The Russian and American sections of the space station are inextricably linked. Russia, for example, provides propulsion for the entire complex, while the U.S. provides power.