Proof positive that the chill in America/Russian relations came in an April 2, 2014 memo from NASA as quoted by SpaceRef.
“Given Russia's ongoing violation of Ukraine's sovereignty and territorial integrity, until further notice, the U.S. Government has determined that all NASA contacts with Russian Government representatives are suspended, unless the activity has been specifically excepted. This suspension includes NASA travel to Russia and visits by Russian Government representatives to NASA facilities, bilateral meetings, email, and teleconferences or videoconferences. At the present time, only operational International Space Station activities have been excepted. In addition, multilateral meetings held outside of Russia that may include Russian participation are not precluded under the present guidance. If desired, our office will assist in communication with Russian entities regarding this suspension of activities.”
This suggests that NASA assurances to the contrary, Vladimir Putin’s imperial ambitions are placing a strain on America’s space partnership with Russia.
The ISS exception is due to the fact that NASA is still dependent on Russia for travel to and from the orbiting space lab, something that the space agency took pains to note in a follow on statement.
“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."
Congress has been reluctant to fully fund Obama administration requests for the commercial crew program from its inception. Partly this is because of expressed skepticism of relying totally on the private sector for human space flight which is combined with a certain squeamishness over the massive subsidies required for these “commercial”: spacecraft. Congress also remains angry over the abrupt cancellation of the Constellation space exploration program that had enjoyed wide bi-partisan support.