ULA, the joint venture between Boeing and Lockheed Martin, uses the RD-180 in its Atlas V rocket. It is working with Jeffrey P. Bezos's Blue Origin to develop a new, American-made engine that could be ready for its new Vulcan rocket by as early as 2019. Aerojet Rocketdyne is also working on a replacement engine.
(Bezos, the founder and chief executive of Amazon.com, also owns The Washington Post.)
The language was added to the Pentagon's spending bill, which was approved by the Senate on Tuesday, 85 to 13.
In a statement, ULA applauded the compromise, saying it "ensures our country’s assured access to space, strengthens competition, protects taxpayers and keeps America’s launch industry healthy for decades to come."