At a ceremony this week at NASA’s New Orleans assembly plant where Boeing is building what will be the most powerful rocket ever to fly, NASA Administrator Jim Bridenstine cheered the “beautiful, beautiful” progress its prime contractor had made on the gigantic and much maligned project. He declared the troubles that have long plagued the development of the rocket’s main section to be in the past.

What he did not mention was the fight brewing behind the scenes over Boeing’s effort to force NASA to fast-track the company’s next offering: a new, enhanced second stage that would give the Space Launch System (SLS) rocket dramatically more oomph than even the mighty Saturn V that sent astronauts to the moon during the Apollo era. Developing the second stage would create another potential financial windfall for Boeing.

NASA, already stung by delays and billions of dollars in cost overruns in the SLS program, is openly opposed to speeding up development of the upper stage. Having spent $34 billion so far on SLS, the Lockheed Martin-built Orion spacecraft and the associated ground systems, a cost that NASA’s inspector general said would grow to $50 billion by 2024, NASA wants to slow down work on a project it fears will suffer the same fate as the SLS main stage: More cost overruns. More delays. No moon landings.

NASA’s budget request for next year was clear about its intentions. Citing “delays and performance issues,” the “final design efforts” on the version of the rocket that would use what’s known as the Exploration Upper Stage, or EUS, are to be “deferred” so that Boeing, the program’s prime contractor, can remain focused on completing the core section of the SLS rocket. That, NASA has said, is key to meeting a White House mandate to return people to the moon by 2024, a program NASA calls Artemis.

In an interview, Bridenstine said that while the upper stage will be a great asset for NASA some day, he said “any plan that requires an EUS to be ready by 2024 is a plan that reduces the probability of success. It’s just not going to be ready.”

While Boeing said its top priority is delivering the rocket’s core stage, it is also pushing aggressively for additional resources, lobbying Congress and trying to win public support.

It’s an effort that demonstrates how the industry stalwart, facing one of the darkest moments in its more than 100-year history after two commercial airline crashes killed 346 people, still wields enormous power, not only over how billions of dollars of taxpayer money is spent but also in shaping national policy — in this case how, when and whether the space agency returns humans to the moon.

But tensions over the upper stage have spilled into the open in a rare public disagreement between NASA and one of its biggest contractors. On Tuesday, after Boeing was contacted by The Washington Post for this story, the company published a blog post saying it was “accelerating work on a powerful new upper stage,” and said “NASA expects to fly the EUS” for its lunar landing mission, known as Artemis III.

That elicited a strong response from Bridenstine, who told The Post in a statement, “NASA believes that there is tremendous value in the Exploration Upper Stage, but no one at NASA believes it will be available by Artemis III.”

For years, government watchdogs have sounded the alarm over Boeing’s management of the SLS program. Boeing is under what’s known as a cost-plus contract, which covers allowed expenses but also ensures a profit for the contractor. Boeing’s contract also has an incentive fee through which it has been awarded tens of millions of dollars despite the poor performance.

Given that history, Boeing’s efforts on the upper stage have rubbed some in NASA the wrong way.

“All of our contractors lobby Congress to achieve what is in their best interest even though it may not be in the best interest of the nation,” Bridenstine said in an interview. “This is another example of that. My job as NASA administrator is to make sure we do what’s right for the country, and for the taxpayer.”

So far, Congress has appropriated several hundred million dollars for the upper stage, which is still in the development phase. Boeing says it can be ready in time for a 2024 moon landing — if it’s given more money, though it has not said exactly how much.

NASA’s Artemis plan is a far cry from the Apollo program, where 12 astronauts walked on the lunar surface, leaving flags and footprints behind. The last mission was in 1972, and no one has been back since then despite attempts by various administrations.

Under President Trump, who has made space a priority, NASA plans to create a permanent presence on and around the moon, allowing for more science and deeper exploration of the solar system.

“This time when we go to the moon, we’re going to stay, with a purpose of learning how to live and work on another world so we can take that knowledge and information to Mars,” Bridenstine said during the event in New Orleans.

To achieve that goal, NASA plans to build a mini space station that would orbit the moon, known as the Gateway, which Bridenstine has called “the cornerstone” of the agency’s lunar plans. The Gateway would allow NASA to access a key region of the moon — the South Pole, where there is water in the form of ice in the permanently shadowed craters.

Water, of course, is “life support,” as Bridenstine said. “It’s air to breathe. It’s water to drink. But it’s also, if you can imagine, rocket fuel.” Its components — hydrogen and oxygen — can be used as propellant, turning the moon, then, into a gas station in space.

The Gateway, Bridenstine said, “is going to enable us to do more science than ever before.”

Because the Gateway would be outfitted with a robust communications system, it could assist in harnessing data from science experiments. One in particular, he said, would look deep into space from the far side of the moon. Normally, the mission would cost about $500 million, he said. But with the Gateway “we’re going to have a communication architecture at the moon and we don’t have to launch these large aperture antennas for communications, we can get high throughput data down to Earth quickly. All of a sudden, that mission goes from $500 million down to $90 million.”

But Boeing has another plan: Go directly to the surface of the moon. But that’s possible only if it has the enhanced upper stage ready in time, which is one of the reasons the company is pushing so hard to have Congress fund it.

The Gateway is a far more complex endeavor, requiring launches of multiple rockets, and the in-orbit assembly of the various components of the station. Going direct is simpler, leading to a higher probability of success, the company argues. Boeing says its plan wouldn’t eliminate Gateway, just give NASA a backup in case the Gateway isn’t ready.

“You don’t want to be ready to go to the moon, but waiting for Gateway,” Jim Chilton, the senior vice president of Boeing’s space and launch division, said in an interview.

NASA, however, is struggling to get Congress to fund the Artemis program and the lunar landers that would ferry astronauts from the Gateway to the moon’s surface. Bridenstine has crisscrossed the country meeting with members, trying to sell the plan and get bipartisan support. But so far his efforts have been met with skepticism.

Boeing, however, is having success on Capitol Hill.

For years, SLS’s chief benefactor has been Sen. Richard C. Shelby (Ala.), the powerful Republican Appropriations Committee chairman who has unabashedly championed the program for the benefits it has brought to his home state, where the program is based. Over the past five years, Boeing has been one of his top campaign contributors, pumping more than $121,000 into his coffers, according to opensecrets.org.

A spokesperson for Shelby said he remains supportive of the upper stage and pointed to the hundreds of millions in past funding, including $300 million for the program in next year’s Senate bill, as evidence of his backing.

But it’s not just Alabama. Construction of the rocket and the Orion spacecraft is spread out so that every state has jobs connected to the program. In all, NASA says it supports about 25,000 jobs across the country, with a total economic impact of $4.7 billion.

In the Senate version of the NASA authorization bill for next year, lawmakers included language dictating that the agency “continue development” of the upper stage so that it could be ready for the third flight of the SLS, or Artemis III, which would be in time to land humans on the moon by 2024.

While there is no House version of the bill, or an appropriation, Boeing’s early success at pushing a compliant Congress to mandate the new upper stage for the third flight, instead of a later one, as is now planned, could upend NASA’s lunar landing plans and put Boeing in the position of redirecting policy that had been set by NASA’s leaders, engineers and scientists who have something other than profits as their priorities.

To meet the White House’s 2024 lunar landing date, NASA has been trying to build a broad coalition of companies, and has said repeatedly that everyone needs to pull together to help make the moon mission possible by 2024.

“When we have one contractor trying to dictate policy that benefits them over the others, it puts the whole program at risk,” said one senior NASA official on the condition of anonymity because the official was not authorized to speak publicly.

In 2017, NASA grew frustrated with the progress of the upper stage and looked at awarding the contract to another bidder. Jeff Bezos’s Blue Origin submitted a proposal to build an upper stage, but was rebuffed. (Bezos owns The Washington Post.) In October, NASA issued a justification to award a sole source contract to Boeing. But since contract negotiations continue, the agency wouldn’t say what the value would be.

While the fight over the upper stage plays out, NASA and Boeing have said they have made tremendous progress with the SLS core. Earlier this month, all four RS-25 engines were mated to the base of the rocket, which is about to be shipped for a key test, known as the “green run,” which would simulate a launch, testing three flight computers and more than 50 avionic units, navigation and control systems.

If all goes well, NASA hopes the rocket will be ready to launch the Orion spacecraft, without people, on a test flight around the moon sometime in 2021.

The team “has hit its stride,” said Chilton, the Boeing senior vice president.