Former NASA astronaut Scott Kelly and Russian space chief engage in Twitter fight

The International Space Station was photographed by one of the STS-98 crew members aboard the Space Shuttle Atlantis following separation of the shuttle and station on February 16, 2001.

(CNN)An extraordinary war of words is transpiring between the head of Russia's space agency and one of NASA's most famous former astronauts as the US-Russian partnership at the International Space Station hits its lowest point since its inception.

Scott Kelly, who famously spent a year in space aboard the station, has been blocked on Twitter by Roscosmos Director General Dmitry Rogozin after Kelly criticized Russia's invasion of Ukraine and Rogozin's repeated threats to pull out of the International Space Station, typically a venue of cooperation immune from geopolitical chaos.
"Get off, you moron!" Rogozin said in a quickly deleted Tweet. "Otherwise, the death of the International Space Station will be on your conscience."
    "Dimon, why did you delete this tweet?" Kelly replied in Russian. "Don't want everyone to see what kind of child you are?"
      In an interview with CNN, Kelly described it as "the first Twitter argument I've ever had."
      On Wednesday, Kelly announced on Twitter — in Russian — that he was returning a medal awarded to him in 2011 by former Russian President Dmitry Medvedev.
      "Mr. Medvedev, I am returning to you the Russian medal 'For Merit in Space Exploration,' which you presented to me," Kelly wrote, according to a translated version of the tweet. "Please give it to a Russian mother whose son died in this unjust war. I will mail the medal to the Russian embassy in Washington. Good luck."
        The tweet came in response to a post from Medvedev that wished women a "Happy Holidays."

        Social media propaganda

        Kelly said in an interview earlier this week that he felt compelled to speak out after Rogozin shared a Roscosmos-produced video showing two Russian cosmonauts floating inside the space station waving goodbye to NASA astronaut Mark Vande Hei, who is supposed to return to Earth with them on a Russian Soyuz spacecraft on March 30.
        Expedition 46 Commander Scott Kelly of NASA rested outside of the Soyuz TMA-18M spacecraft minutes after he and cosmonauts Mikhail Kornienko and Sergey Volkov of Roscosmos landed on March 2, 2016, in Kazakhstan.
        "If he's going to act like a child, then I'm going to treat him like one," Kelly said. "It's just unimaginable that the Russian space program would leave a person behind in space that they were responsible for bringing home. I don't see that happening."
        But Kelly quickly reconsidered after remarking how he also thought it