“Russia‘s deputy prime minister, Dmitry Rogozin, has announced it will halt the export of rocket engines crucial to the US military defence and space programmes. The move marks a serious deterioration in US-Russian cooperation in space, which for two decades had remained largely above Earthly politics. It could prove a serious set back for the ailing US space programme. Although Nasa relies on the Atlas V to launch some of its deep space probes, most are used to put US spy satellites and other classified payloads into space. The new restrictions will make it difficult for the US to import any of the engines because it will hard to prove the hardware is not destined for a military programme.”
http://www.theguardian.com/science/2014/may/15/us-space-military-programme-russia-sanctions