Raytheon Technologies Corp. will contest the acquisition of Aerojet Rocketdyne Holdings Inc. by Lockheed Martin Corp., according to media reports.

In a story published Wednesday by Bloomberg, Raytheon Chief Executive Greg Hayes was quoted as saying that the deal gives them pause based on competition going forward.

“They (Aerojet) are a huge supplier to us, and if that merger actually happens, you don’t have an independent supplier on the solid-rocket-motor side,” Hayes said on Wednesday at the Barclays Industrial Select virtual conference, according to the Bloomberg story.

Lockheed in Bethesda, Md., announced back in December it was acquiring Aerojet Rocketdyne in El Segundo in a transaction valued at $5 billion.

Aerojet Rocketdyne has a long-time presence in the San Fernando Valley where its Chatsworth campus is currently making the rocket engines for NASA’s Space Launch System that will take humans back to the moon and possibly to Mars.

Hayes said the company would relay its concerns about the deal to the U.S. antitrust authorities and the Defense Department, the Bloomberg story said.

Lockheed has said it expects to close the purchase in the second half of the year, subject to regulatory review and approval by Aerojet shareholders, according to Bloomberg.