WASHINGTON – Sen. John McCain (R-Ariz.) wants the Air Force to prove that when it buys an Atlas 5 rocket and the subsequent Russian RD-180 rocket engine from United Launch Alliance, none of the money goes to Russian leaders under sanctions from the U.S. government.

McCain filed an amendment May 25 to the Senate Armed Services Committee’s version of the defense authorization bill for 2017 requiring certification from the Treasury Department that any new Air Force contract to use the Atlas 5 rocket does not violate sanctions. The Senate is voting on amendments for the National Defense Authorization Act this week.

In February, McCain said Russian Deputy Prime Minister Dmitry Rogozin and Sergei Chemezov, an adviser to Russian President Vladimir Putin, have new roles overseeing Russia’s state-run space sector and as such the State, Treasury and Commerce departments should reassess whether the purchase of the RD-180 engine violates sanctions.

ULA buys the RD-180 from Florida-based RD-AMROSS, a joint venture between Energomash and Pratt and Whitney of Hartford, Connecticut. RD-AMROSS, in turn, buys the engines from NPO Energomash of Khimki, Russia.

While RD-AMROSS has said the men do not financially benefit from the sale of the engine, McCain pointed out that Energomash is essentially a subsidiary of the state space corporation Roscosmos. Rogozin is the chairman of the Roscosmos board and Chemezov is a board member.

Both men were among the first Russian officials President Barack Obama sanctioned during the Crimean crisis by freezing their U.S.-based assets and preventing them from entering the country. Earlier this year, the Treasury Department told the Defense Department that it reviewed the men’s new roles and that sanctions did not apply to the engine sales.

McCain’s move is the latest in a series of legislative actions this spring related to the engine, pitting the chamber’s authorizers and appropriators against each other on the issue for the second consecutive year.

Congress banned future use of Russian engines for U.S. national security launches in the National Defense Authorization Act for 2015 as a response to Russia’s actions near the Ukraine border in 2014.

As part of the 2017 authorization bill, the SASC suggested providing limited relief from the ban, giving ULA access to nine engines until a new American engine is ready around 2022. (ULA executives have committed five of those engines for civil and commercial launches) The House has approved an authorization bill that allows for the use of up to 18 new engines.

But Senate appropriators fear that by limiting the number of engines the Air Force can use, they may be stifling competition and inadvertently handing SpaceX a monopoly for national security launches.

In their version of the defense spending bill for 2017, the Senate Appropriations Committee allows the Air Force unfettered access to the RD-180 if the engine will be used for a competitive launch.

The bill says “that notwithstanding any other provision of law” the Air Force could award a launch contract to any certified company “regardless of the country of origin of the rocket engine that will be used on its launch vehicle, in order to ensure robust competition and continued assured access to space.”

Senators, led by Richard Durbin (D-Ill.) and Richard Shelby (R-Ala.), inserted nearly identical language into last year’s omnibus spending bill and in the process infuriated McCain, the chairman of the Senate Armed Services Committee, who viewed the step as an end-around his committee.

There is a catch, however, to the language in the appropriators’ bill for next year. Because the appropriations language contradicts the authorization bill, according to a report from the Congressional Research Service, the bill would only stand if it passes both the House and Senate after the NDAA. That appears likely as authorization bills routinely pass months before appropriations bill in recent years.

Meanwhile, Bob Work, the deputy secretary of defense, said May 23 if the Air Force did not have access to the RD-180, “the cost impacts and disruption” would be significant. In a letter to Sen. Bill Nelson (D-Fla.), Work said the cost of moving Atlas 5 missions to ULA’s other rocket, the more expensive Delta 4, would be between $1.5 billion to $5 billion. He also suggested that if ULA could not compete for national security launch missions due to a ban on the Atlas 5 it could force the Boeing-Lockheed Martin joint venture to shut its doors.

“If ULA is no longer competitive for these missions, it is unclear whether ULA would have sufficient funds available to continue to invest in a next-generation domestic launch vehicle, or even to stay in business,” he said.