Some time after the beginning of the current Ukraine crisis, it became clear that the US and Russia would be forced to cooperate in one area regardless of how much other diplomatic relations might deteriorate: space. The International Space Station at the time was manned by Expedition 39's three Russian and two American members, led by a Japanese astronaut.
Their mission finished and they returned to Earth today, as it happens, in one of Russia's Soyuz spacecraft. Since the retirement of the last Space Shuttle, Atlantis, in 2011, the US has had no way of putting humans into orbit - only Russia and China do. Historically, the International Space Station was born out of the geopolitical climate in the aftermath of the collapse of the Soviet Union, a time when history was believed to have ended and peaceful scientific cooperation between the largest and most powerful nations of the world was not only possible, but inevitable. That Nasa would have a gap between retiring one crew-carrying craft and introducing its replacement was thought to be an annoying inconvenience, but not any kind of substantial threat to its ability to carry out any missions at all.
On 4 March, Nasa administrator Charlie Bolden told a press conference that there was nothing to worry about when it came to the ISS:
I think people lose track of the fact that we have occupied the International Space Station now for 13 consecutive years uninterrupted, and that has been through multiple international crises. I don't think it's an insignificant fact that we're starting to see a number of people with the idea that the International Space Station be nominated for the Nobel Peace Prize. It's not trivial. It has continued to exist and continued to function with people from a variety of cultures and beliefs, but we all are focused on the mission of the International Space Station."
It seems Bolden was too optimistic, and not just about the ISS. Russian deputy prime minister - and head of Roscosmos, its space agency - Dmitry Rogozin has announced that the country has denied a US request to extend the ISS's mission life beyond 2020, and that there has also been a further ban on the export of Russian-made MK-33 and RD-180 motors to Boeing and Lockheed Martin because they're used in the rockets that put US military satellites into space.
Since the ISS is co-owned by those nations that built the modules, it requires the cooperation of each of them when making decisions like extending its operation life - which had happened already, as the original end date had been scheduled for 2016. While it would have possibly been a stretch, it was America's hope to convince everyone else that a further extension to 2024 was possible. However, Russia is well aware that its modules (like the Zvezda Service Module, which contains the stations' life support systems) could detach and operate as an independent station of their own, or even as the basis of a completely new station post-2020. The other modules, such as America's Destiny science laboratory, cannot.
Admittedly, the proposed use of the Russian components is quite cool - it's called OPSEK, and would effectively be an in-orbit station and workshop where spacecraft destined to explore other planets could be built, stationed and refueled - but it would represent the disintegration of what may have only been a brief period of international space cooperation. Russia has made noises about collaborating with other Asian countries on OPSEK while deliberately excluding Nasa and the European Space Agency, and that's a great shame for those of us who had hoped humanity would be exploring the cosmos hand-in-hand.
At the moment, Nasa's contract with Roscosmos for the use of seats on the Soyuz runs only until 2017, by which time there are expected to be alternatives available from the US. Elon Musk, of SpaceX and Tesla Motors fame, had won - but subsequently lost again - a case for an injunction on the United States Air Force for its $70bn contract with a Boeing-Lockheed Martin conglomerate (called United Military Launch Alliance) for the use of Delta IV and Atlas V rockets for satellite launches. Not only did Musk argue that the contract violated US law mandating that multiple private companies should be allowed to compete for government contracts, but also that the use of Russian engines in those rockets violated the sanctions against Russia introduced in the wake of the Ukraine crisis.
Now that the Russian government has banned rocket engine exports to the US, it gives SpaceX an extra commercial opportunity. Not only can it propose the use of its American-made Falcon 9 rockets - which are already contracted by Nasa for ISS resupply missions - as a replacement in the most prestigious military launches, but it also gives Musk's outfit a distinct advantage over its rivals in the soon-to-open bidding process to lead development on Nasa's Commercial Crew Program. While UMLA claims to have at least two years' worth of engines stockpiled, allowing continued use of the Delta IV and Atlas V for now, it's likely Nasa will want to reduce uncertainty to a minimum. Nasa's own Space Shuttle successor, the Space Launch System, is not expected to be ready until after 2020, and is intended to be capable of journeying as far as the Moon or even Mars; conversely, the contracts Nasa will be awarding under the CCP are for craft that can deliver crews into the ISS's low orbit, and are likely to be ready by 2017.
There is the possibility that the engine ban could be lifted if, Rogozin has said, Russia was guaranteed that they wouldn't be used "in the interests of the Pentagon", but that won't reassure Nasa - and since the ISS has now become a bargaining chip in US-Russian relations, it gives us a worrying view of a return to a space race we had thought had finished long ago.