headlines: Russia Says It Will Quit the International Space Station After 2024
articles: Mr. Putin’s response: “Good.”
  
  With tensions between Washington and Moscow rising after Russia’s invasion of Ukraine in February, Russian space officials including Dmitry Rogozin, Mr. Borisov’s predecessor, had made declarations in recent months that Russia was planning to leave. But they all left ambiguity about when it would happen or whether a final decision had been made.
  
  If Russia follows through, it could accelerate the end of a project that NASA has spent about $100 billion on over the last quarter-century and set off a scrambling over what to do next. The space station, a partnership with Russia that also involves Canada, Europe and Japan, is key to studying the effects of weightlessness and radiation on human health — research that is still unfinished but needed before astronauts embark on longer voyages to Mars. It has also turned into a proving ground for commercial use of space, including visits by wealthy private citizens and the manufacturing of high-purity optical fibers.
  
  An official at the White House said the United States had not received any formal notification from Russia that it would withdraw from the space station, although officials have seen the public comments.
  
  “We are exploring options to mitigate any potential impacts on the I.S.S. beyond 2024 if in fact Russia withdraws,” said John Kirby, a spokesman for the National Security Council.