The space partnership between the United States and Russia, which dates back to the early 1990s with an astronaut-cosmonaut exchange program, so far has remained outside the political rancor and economic ramifications stemming from Russia's annexation of Ukraine's Crimea peninsula earlier this year.
But the escalating tensions now threaten the future of the International Space Station, or ISS, a 15-nation research laboratory overseen by the United States and Russia. Rotating crews of NASA astronauts and Russian cosmonauts, along with members of the European, Canadian and Japanese astronaut corps, have lived together aboard the orbital outpost since November 2000. Construction, however, was finished just three years ago.
VIDEO: New Digs for the Space Station
With science operations finally in full swing, the Obama Administration last year confirmed NASA's plan to keep the station in orbit until at least 2024, four years longer than original projections.
Russia, however, now has other ideas.