Aerojet Rocketdyne has reportedly offered to acquire the United Launch Alliance for $2 billion, in what would be a major shakeup in the space launch industry and cap a tumultuous 18 months in an industry long dominated by a single player.

For years, ULA enjoyed the spoils of a monopoly in the hugely lucrative—and complicated—industry of rocket launches. The United Launch Alliance, a joint venture between Boeing and Lockheed Martin, had the combined might of the two defense giants, and no competition when it came to launching national security satellites into space for the Pentagon and intelligence agencies.

Times were good.

But then came along a feisty entrepreneur, with a big ego and big dreams, eager to get into the space business and upend an industry that he viewed as scerlotic. Elon Musk’s SpaceX sued for the right to compete against ULA for those contracts, and was eventually certified to do so.

But along the way, the billionaire entrepreneur kicked up a lot of dust. He accused the government of moving too slowly to certify SpaceX. He lambasted ULA for using Russian-made engines on their rockets at a time when tensions were mounting between U.S. and Russia over the Ukraine. He promised to compete the contracts for far cheaper, and publicly speculated that his competition benefited from a revolving door between the Pentagon and the defense industry.

SpaceX had already won contracts from NASA to deliver astronauts and cargo to the International Space Station, and ULA took its threats to disrupt the national security launch industry seriously. It replaced its CEO with Tory Bruno, who vowed to “literally transform the company” so that it could compete. Bruno soon announced a partnership with Jeff Bezos’ Blue Origin to build an American-made rocket engine. (Bezos owns The Washington Post.) And last summer, ULA unveiled a new, reusable rocket, the Vulcan, which would help the company lower costs.

But it still faces massive hurdles.

Led by Sen. John McCain (R-Ariz.), Congress has moved to limit the number of RD-180 engines ULA could use. Since the RD-180 powers ULA’s Atlas V rocket, that could have a huge impact on ULA’s business. And after settling the lawsuit with SpaceX, the Air Force seemed grateful to have another company able to compete for its launch contracts for the first time in a decade.

"Ultimately, leveraging of the commercial space market drives down cost to the American taxpayer and improves our military's resiliency,” said Air Force Secretary Deborah Lee James said in May.

All of which may make ULA’s board eager to sell—for the right price. (The Wall Street Journal and Reuters have reported that a deal could be announced as early as next week.)

After a decade in the business, ULA has been a stalwart and a go-to provider of launches for the government. Its disappearance would mark the end of an era in the space business, though Boeing and Lockheed would remain major players. Boeing won a contract to ferry astronauts to the space station and last week unveiled the new name of its capsule, the CST-100 Starliner. Lockheed makes the Orion capsule, which would be used on the massive new Space Launch System rocket being developed by NASA. It is also competing for the contract to fly cargo to the space station.

Aerojet was also hoping to build an engine that could replace the Russian RD-180, but was considered by ULA to be a backup to the engine that Bezos' Blue Origin is developing. If Aerojet acquires ULA, it's not clear what affect that would have on the engine selection.

On Twitter, Bruno, ULA's CEO, declined to comment. An Aerojet Rocketdyne spokesman did not immediately respond to a request for comment.