WASHINGTON — When the House Armed Services Committee took up its annual defense authorization bill in April, Rep. Mike Rogers (R-Ala.) added a provision meant to block the U.S. Air Force from spending precious propulsion funds on anything other than development of a replacement for the Russian RD-180 engine that powers the Pentagon’s workhorse Atlas 5 rocket.

“Let me be clear. We have a Russian engine problem. But we do not have a launch vehicle problem,” Rogers told an industry forum here around the same time the strategic forces subcommittee he chairs was drafting the space sections of the 2017 National Defense Authorization Act, which sets policy and spending guidance for the entire Defense Department.

Rogers’ main-engine-only stance put him at odds with United Launch Alliance, which wants to use Air Force funding to develop Vulcan as a partially reusable successor to the Atlas 5 rocket ULA build in Rogers’ home state.

By the time the House Armed Services Committee completed its markup April 28, the HASC’s version of the NDAA had been amended — with Rogers support, as it turns out — to let the Air Force spend up to 25 percent of its space propulsion budget on launch projects other than developing a new main-stage rocket engine.

The compromise was good news for Orbital ATK, SpaceX and United Launch Alliance — which won $130 million worth of contracts this year to work on new upper stages and next-generation launcher concepts — but a bit of a setback for Aerojet Rocketdyne, which is getting $115 million from the Air Force this year to work on the AR1 engine it is pitching as a drop-in replacement for the RD-180.

Now, as the NDAA heads to the floor for a vote by the full House of Representatives as soon as next week, HASC members — including Rogers— are pushing amendments that would further relax the limits on what the Air Force can spend next year on projects aimed at producing a new next-generation launcher, not just a new main engine for ULA’s reliable-but-expensive Atlas 5.

Rep. Adam Smith (D-Wash), the top Democrat on the House Armed Services Committee, submitted an amendment to the House Rules Committee that would simply raise the cap on non-main-engine spending to 31 percent from the 25 percent cap the HASC already approved.

Rogers submitted his own amendment by the May 11 deadline that would likewise raise the cap to 31 percent but also add a new proviso: the Air Force, which is requiring its industry partners to co-fund these developments efforts, would have to make clear the government could ultimately switch suppliers if necessary.

Smith’s amendment leaves it up to the Pentagon to decide whether it needs to assert the government’s production rights. It would also give the Air Force easier access to next year’s propulsion money by dropping a provision that would fence off 10 percent of the money until the Secretary of the Air Force submits a compliance report to Congress.

HASC was preparing the NDAA to go to the House floor as its Senate counterparts were meeting in closed session to mark up a competing version of the bill. Space sections of the bill were marked up buy the Senate Armed Services strategic forces subcommittee May 10. The full committee is taking up the bill May 12-13.

Meanwhile, the Air Force and industry are still waiting to see how the $296 million the White House requested for rocket propulsion system work fares when the House Appropriations Committee marks up its $517 billion defense spending bill May 17.