The international space station partnership has long endured the ups and downs in relations between Russia and the West, but recent events and statements might be worrisome to those who favor extending the life of the orbital outpost beyond 2020, as the United States has proposed.

During a press conference July 28 — the day before the launch of Europe’s fifth and final Automated Transfer Vehicle (ATV) cargo freighter to the station — a senior official with Russia’s Roscosmos space agency cited tensions over Ukraine as the reason Moscow has yet to approve continued participation beyond 2020. Alexey Krasnov, head of the space station program at Roscosmos, said he is eager to begin ordering the hardware necessary to extend the station’s life but not optimistic of securing government approval to do so this year. 

Mr. Krasnov’s remarks came roughly two-and-a-half months after Russian Deputy Prime Minister Dmitry Rogozin said Russia would in fact end its participation in station after 2020. This was after the U.S. government imposed sanctions on Mr. Rogozin and other Russian officials in response to Russia’s meddling in Ukraine and specifically its annexation of Crimea.

Mr. Rogozin’s declaration was taken with a grain of salt by many space policy experts who assumed cooler heads would prevail over time. But the situation in Ukraine has only gotten worse, punctuated by the downing of a Malaysian civilian jetliner with nearly 300 people aboard by what U.S. authorities say was a sophisticated Russian anti-aircraft missile operated by Ukrainian separatist forces. The U.S., European and Canadian governments are imposing or preparing harder-hitting sanctions, and fighting in areas of eastern Ukraine has intensified.

Despite all this, operations aboard the international space station have continued, seemingly unaffected. Russia launched three new crew members May 28, for example, and cargo vessels continue to come and go — the ATV 5 that launched July 29 was slated to dock with the station Aug. 12. Mr. Krasnov said Roscosmos and its space station partners continue to work well together even as relations between Washington and Moscow slide toward Cold War depths.

It’s not surprising under the circumstances that Russia hasn’t jumped at the U.S. proposal to extend station operations to 2024, and to be fair, none of the other partners has either. All are wrestling with budget difficulties, while in Europe the matter is tied up in very challenging negotiations over the future of its launch vehicle sector. Senior NASA officials have said it could be some time before these countries decide their future roles in space station.

But without Roscosmos, it is hard to see how the program could continue. Not only is Russia solely responsible for transporting crews to and from the station, but following the last ATV mission it will possess the only capability to deorbit the facility in a controlled manner. NASA aims to field an independent crew capability starting around 2017 but currently has no plans for a propulsion module capable of guiding the 420,000-kilogram station to a controlled re-entry over an uninhabited stretch of the Pacific Ocean.

That means unless and until Russia commits to participation beyond 2020, any organization — commercial or otherwise — contemplating an investment in research aboard the space station might have to think twice, as such experiments can take years to develop and launch. It also means the commercial crew taxis being developed with hundreds of millions of dollars in U.S. taxpayer assistance might have no place to go after just a couple of years of operation.

Russia, of course, has plenty at stake here too. The country is justifiably proud of its legacy in human spaceflight — its program obviously was first and remains the most prolific — but has yet to articulate a credible alternative program for beyond 2020. Delivering astronauts to and from the station also is an important source of hard currency for Roscosmos and Russia’s space industry. 

It therefore seems very likely that Russia — assuming the situation in Ukraine doesn’t come completely unhinged — eventually will commit to extending station operations. When that might happen is anyone’s guess, but it’s probably safe to say Moscow won’t act while the imposition of Western economic sanctions — and they are warranted, Russia’s retaliatory measures notwithstanding — is still fresh on people’s minds.  

In the meantime, space station researchers and advocates will have to exercise a little faith and patience. Moscow might not be in any hurry to give Washington something it has said it wants, but Russian authorities surely recognize it’s still in their interest to do so.