The U.S. Court of Federal Claims issued a preliminary injunction April 30 banning the Air Force or national security launch provider United Launch Alliance (ULA) from purchasing the Russian-made RD-180 rocket engine due to United States sanctions against Russia.

The court found that because President Barack Obama on March 16 issued sanctions against Russian Deputy Prime Minister Dmitry Rogozin, who it said is also head of Russia’s defense industry and space program, it is authorized to temporarily prohibit the transfer of the RD-180 to the Air Force or ULA. The ruling also bars purchases or monetary transfers between the Air Force/ULA and any company or individual controlled by Rogozin until the Commerce, State and Treasury departments say such purchases or payments will not violate the March 16 sanctions.

The United States on Monday also issued additional sanctions against Rogozin as well as restrictions banning export or re-export of any “high technology defense articles or services.” Space Exploration Technologies Corp. (SpaceX) alleged in its Monday lawsuit that that NPO Energomash, maker of the RD-180, is Russian state-owned and operated firm. The injunction does not apply to any purchase orders monetary payments placed to NPO Energomash before Wednesday.

The Air Force in 2013 awarded ULA its 36 core “block buy” for national security launches in the service’s Evolved Expendable Launch Vehicle (EELV) program. SpaceX Monday filed its lawsuit to force the Air Force to open up the block buy to competition. ULA spokeswoman Jessica Rye said Thursday the federal government has ordered 14 cores, and made payments against, 14 of the 35 cores in the block buy. Rye said that extra launch core was originally in the block buy, but was later moved to a deal from fiscal year 2012.

ULA General Counsel Kevin MacCary said Thursday in a statement the company is deeply concerned with the ruling and will work closely with the Justice Department to resolve the injunction expeditiously. MacCary said, like ULA, NASA and numerous other companies lawfully conduct business with the NPO Energomash, other Russian state-owned industries and Russian Federation agencies. Rye declined to say who these companies were, but said the State Department knows of the numerous activities in aircraft, space, oil and gas, telecommunications and materials that are mostly state-owned businesses in Russia.

“This opportunistic action by SpaceX appears to be an attempt to circumvent the requirements imposed on those who seek to meet the challenging launch needs of the nation and to avoid having to follow the rules, regulations and standards expected of a company entrusted to support our nation’s most sensitive missions,” MacCary said.

SpaceX said Thursday in a statement the court took a “prudent step” toward understanding whether ULA’s sole-source contract violates U.S. sanctions by sending taxpayer money to Russia for the RD-180 engine.

“That question, as well as others relating to the risks posed by dependence on Russian-made engines and the need to open competition for the Air Force space launch program, are timely and appropriate,” the company said.

House Armed Services Committee (HASC) member and pro-EELV competition lawmaker Loretta Sanchez (D-Calif.) said Thursday in a statement she believes Russia’s actions in Crimea are unacceptable and sanctions are warranted, but U.S. ties to Russia are clearly multi-layered. Sanchez wants to open national security launch services to competition.

“However, I hope the preliminary injunction against ULA might urge the Defense Department to expedite the process of creating a (next-generation rocket engine) production line here in the U.S.,” Sanchez said.

Emails to the Air Force, ULA, Commerce and State departments for comment were not returned by press time. ULA uses the RD-180 in its Atlas V launch vehicle.

The RD-180 is distributed in the United States by RD AMROSS, a joint venture of NPO Energomash and Pratt & Whitney, a division of United Technologies Corp. [UTX]. ULA is a joint venture of Lockheed Martin [LMT] and Boeing [BA].