WASHINGTON — L3Harris on Friday announced it had completed its acquisition of Aerojet Rocketdyne, adding a company with broad expertise in building rocket engines and propulsion systems to its portfolio.

The $4.7 billion deal, which the companies first announced in December 2022, will give L3Harris more opportunities in the missile defense system, hypersonic, and advanced rocket engine markets, the company said in a Friday statement.

“I’m thrilled to welcome more than 5,000 employees to the L3Harris team today,” L3Harris chief executive Christopher Kubasik said. “With national security at the forefront, we’re combining our resources and expertise with Aerojet Rocketdyne’s propulsion and energetics capabilities to ensure that the Department of Defense and civil space customers can address critical mission needs globally.”

Ross Niebergall, who until now was vice president and chief technology officer at Aerojet Rocketdyne, will be the president of L3Harris’ new Aerojet Rocketdyne segment. The company said Niebergall will be responsible for the Aerojet division’s business strategy, financial performance, execution of programs and growth.

“Our customers demand a competitive environment that produces innovative, agile solutions,” Niebergall said. “We will expand on the strong Aerojet Rocketdyne heritage to enhance production and deliver on those expectations.”

By Friday morning, Aerojet Rocketdyne’s website had been redirected to L3Harris’ home page, and it is now known as Aerojet Rocketdyne, an L3Harris Technologies company. L3Harris’ other business segments are space and airborne systems, integrated mission systems, and communication systems.

Lockheed Martin’s previous attempt at acquiring Aerojet for $4.4 billion ran aground amid federal regulator’s antitrust concerns. The Federal Trade Commission sued to block that deal in January 2022, and the following month, Lockheed canceled plans to buy Aerojet.

In January 2023, a month after L3Harris announced its own acquisition plans, Sen. Elizabeth Warren raised concerns to the FTC. Earlier this month, she also asked the Defense Department to carefully review the deal for any potential conflicts.

The FTC on Wednesday told L3Harris it would not block the deal, and the company told investors in a letter that it would swiftly move to close its purchase of Aerojet.