WASHINGTON — Elon Musk aggressively elbowed his way into the space launch business over the past two decades, combining engineering genius and an entrepreneurial drive with a demand that the U.S. government stop favoring the big, slow-moving contractors that had long dominated the industry.

Today, it is Musk who is dominant. His company, SpaceX, is the primary provider of launch services to NASA and to the Pentagon. His rockets carry far more commercial satellites into orbit than anyone else’s, including those for his own Starlink communications network. He has set new standards for reaching space cheaply and reliably.

But in one striking way, the former outsider has come to resemble the entrenched contractors he once fought to topple: He is increasingly using his vast power and influence to try to keep emerging rivals at bay, his competitors say, even as his success is prompting qualms within the government about such heavy reliance on a mercurial billionaire.

The new generation of space entrepreneurs trying to emulate Musk is sufficiently concerned about what they see as his anticompetitive tactics that some of them are now willing to take him on publicly.

Tim Ellis started Relativity Space after being inspired by Musk’s pursuit of a rocket that could carry humans to Mars. Then he heard from other industry executives that individuals with ties to SpaceX were trying to block his efforts to raise money for his own Mars project.

Jim Cantrell worked with Musk at the founding of SpaceX in 2002. When he started to build his own launch company, Phantom Space, two potential customers told his sales team they could not sign deals because SpaceX inserts provisions in its contracts to discourage customers from using rivals.

Peter Beck, an aerospace engineer from New Zealand, met in 2019 with Musk to talk about Beck’s own launch company, called Rocket Lab. Several months later, SpaceX moved to start carrying small payloads at a discounted price that Beck and other industry executives said was intended to undercut their chances of success.

“I don’t think this is an accidental monopoly,” Beck said in an interview about SpaceX and Musk. “These are business decisions that are being made.”

None of these executives said they had taken legal action against SpaceX. And no one in the industry disputes that Musk and SpaceX deserve enormous credit for making spaceflight more affordable and almost routine.

But his tactics are generating a backlash within the industry. And they are adding to concerns in the government about relying so heavily for a critical technology on someone known as much for his divisive public statements, his increasingly outspoken political positions that are at odds with U.S. policy and his deep business ties to rivals like China as he is for his engineering prowess.

Musk endorsed an antisemitic theory late last year on his social media platform X. He has nurtured relationships with right-wing leaders around the world. And he has publicly stated that Russia will not lose its war against Ukraine, endorsing an argument that the United States should not have provided Ukraine with additional military assistance.

“Elon Musk’s rhetoric and behavior undermines his credibility and reliability on a global scale,” said Sen. Jeanne Shaheen, D-N.H., who this spring questioned Pentagon officials about Musk. “Commercial services, including SpaceX, that do business with the U.S. government need to be thoroughly vetted to ensure that the U.S. military can depend on them in times of crisis.”

Last month, a bipartisan group of 36 House lawmakers sent a letter to Frank Kendall, the Air Force secretary, urging him to make sure that the Air Force pushes for “increased competition among launch providers.”

SpaceX did not respond to requests for comment. But when interviewed at a recent industry conference, one of SpaceX’s senior executives disputed any suggestion that the company was trying to force other new launch companies out of business.

“I don’t buy that, not at all,” Gary Henry, who works on national security contracts for SpaceX after earlier posts with Boeing and the Air Force, said in the interview. “I can see if you are on that end of it, it might feel that way. But people in those companies who know us personally know that is not the case.”

In a presentation to SpaceX employees in Texas this year, Musk did not directly address claims of anticompetitive behavior from rivals in the launch industry. But he noted that SpaceX had carried cargo to orbit, or agreed to do so in the future, for competitors in related businesses including Amazon, Telestat, OneWeb and Apple-backed Globalstar, all of which are rivals of SpaceX’s Starlink communications network.

“We’re actually on contract to launch Amazon’s Kuiper constellation,” Musk said, evoking a round of laughter from the gathered SpaceX employees. “And we treat everyone fairly.”

SpaceX’s defenders also point out that the launch business appears to be growing more competitive, not less.

Jeff Bezos’ Blue Origin is close to its first launch for its New Glenn rocket. Rocket Lab is building what it calls Neutron, and Relativity Space is working on its Terran R, among other new entrants. After years of delays, Boeing is soon expected to start launching NASA astronauts into space on its new Starliner spacecraft.

For now, though, the ability of the United States to reach orbit, particularly for its most vital classified military and spy satellites, remains largely dependent on Musk and his Falcon 9 rocket.

“Heaven forbid we have a mishap with a Falcon 9 launch,” said Col. Richard Kniseley, who helps run Space Force’s Commercial Space Office. “That means it is grounded, right? And that means we could be without launch. So that’s where my concern is.”

SpaceX has collectively been awarded $14.7 billion in federal launch prime contracts over the past decade, according to an analysis performed by The New York Times by the Center for Strategic and International Studies.

Last year alone, SpaceX secured $3.1 billion in federal prime contracts, according to the data, nearly as much as the combined amount the federal government committed for space transportation and related services from its nine competitors, from giants like Boeing and Northrop Grumman to startups like Blue Origin.

SpaceX is privately held, so it does not release revenue figures, but Payload, an industry research site, estimated that nearly 60% of SpaceX’s launch-related revenue last year came from the federal government.

This means that despite Musk’s early disdain for government subsidies granted to his rivals, including Lockheed and Boeing, SpaceX’s own rise has been bankrolled in large part by NASA and the Pentagon.

At the same time, SpaceX has increasingly adopted business tactics that Musk once condemned, including expanding its lobbying presence in Washington and hiring top Pentagon and NASA executives after they played key roles in awarding contracts to SpaceX.

Beck, the CEO of Rocket Lab, started the company in 2006, just four years after SpaceX was created and before SpaceX had sent its first rocket to orbit.

Since then, Rocket Lab’s Electron launch vehicle has had more than 40 successful trips to orbit, delivering almost 200 satellites to space at one of the lowest costs in the industry.

Now the second most frequent orbital commercial launch company globally behind SpaceX, Rocket Lab is moving to build Neutron, a larger rocket that will compete directly with SpaceX’s Falcon 9.

Beck said he had observed early on that SpaceX was willing to go after its business rivals.

He and other industry executives said they were convinced that SpaceX had set the price for its Transporter service — where small satellite companies can book slots on a Falcon 9 launch — with the explicit goal of undermining the financial plans of emerging competitors.

Transporter’s low price — initially $5,000 per kilogram — was below what some industry executives calculated was SpaceX’s basic cost. They concluded that SpaceX could only offer such a low price by subsiding those flights with some of its government contracting revenue.

More recently, SpaceX started what it called Bandwagon, which offers satellite makers launches to orbits that provide them better coverage over key sections of the world. SpaceX is selling these flights at far below its own costs to undermine its competition, Beck said, citing his own estimates.

“Bandwagon is like, the most bold and obtuse anticompetitive thing you can do,” said Beck, whose company charges about $21,500 per kilogram for its launches to specific orbits.

Henry disputed that SpaceX might be using its market dominance to hurt its competitors.

“We make money on all our launches,” he said.

Flights that carry multiple private and government payloads on a single Falcon 9 launch, he said, are benefiting the commercial space industry by making it more affordable for small firms to get satellites into orbit.

Ellis of Relativity Space said SpaceX had made explicit and repeated efforts to limit the growth of his business.

“Every single funding round that was done once we started to become a larger company, and every single customer deal we have signed, has been followed with a swift and large number of outreach calls from SpaceX to all of those entities berating them for doing things with us,” he said. “This is not theoretical.”