WASHINGTON — A NASA decision announced April 2 to suspend “the majority of its ongoing engagements with the Russian Federation” over the situation in Ukraine carves out a big exception: the international space station.

Because Russia’s three-person Soyuz capsules are currently the only spacecraft in service capable of carrying crew to and from the space station, NASA really has no choice but to continue working with Russia’s space agency, Roscosmos, on this program. Cutting all ties to Russia over the annexation of Crimea would require NASA to vacate the space station.

What’s not clear from the 176-word statement NASA headquarters released several hours after an internal memo leaked to the media is what, if any, other programs will be affected by this policy.

While NASA and Roscosmos are joined at the hip on the ISS program, the two agencies don’t frequently partner on nonhuman spaceflight projects. 

There are, of course, exceptions. NASA’s Mars Curiosity rover, for example, is carrying a Russian-built radiation detector. If the rover was still in development, that could be a big problem. Thankfully, Curiosity — Russian instrument and all — launched nearly two-and-a-half years ago and is a couple months away from completing its primary mission. 

Depending how long the ban stays in place, NASA officials could also be barred from attending the 40th Committee on Space Research (COSPAR) Scientific Assembly in Moscow Aug. 2-10 and the 29th Congress of the International Council of the Aeronautical Sciences in St. Petersburg in September. 

Here’s NASA’s statement:

Given Russia’s ongoing violation of Ukraine’s sovereignty and territorial integrity, NASA is suspending the majority of its ongoing engagements with the Russian Federation.  NASA and Roscosmos will, however, continue to work together to maintain safe and continuous operation of the International Space Station. NASA is laser focused on a plan to return human spaceflight launches to American soil, and end our reliance on Russia to get into space.  This has been a top priority of the Obama Administration’s for the past five years, and had our plan been fully funded, we would have returned American human spaceflight launches — and the jobs they support — back to the United States next year.  With the reduced level of funding approved by Congress, we’re now looking at launching from U.S. soil in 2017.  The choice here is between fully funding the plan to bring space launches back to America or continuing to send millions of dollars to the Russians.  It’s that simple.  The Obama Administration chooses to invest in America — and we are hopeful that Congress will do the same.

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Brian Berger is editor in chief of SpaceNews.com and the SpaceNews magazine. He joined SpaceNews.com in 1998, spending his first decade with the publication covering NASA. His reporting on the 2003 Space Shuttle Columbia accident was...