The addition of Aerojet to Northrop’s team guarantees that the nation’s only two manufacturers of large solid rocket motors will be part of the GBSD program.

NATIONAL HARBOR, Md. — Northrop Grumman announced on Monday that Aerojet Rocketdyne will join its Ground Based Strategic Deterrent team to develop a modernized intercontinental ballistic missile for the U.S. Air Force.

The GBSD — an estimated $63 billion program to replace the Minuteman 3 intercontinental ballistic missile — was expected to be a two-horse race between Northrop Grumman and Boeing. But Boeing decided to drop out after it concluded that Northrop Grumman’s dominance of the solid rocket motors market would give it an overwhelming pricing advantage it could not compete against.

Aerojet Rocketdyne is the only other U.S. manufacturer of large solid rocket motors, and in recent years it had lost significant market share to Orbital ATK which in 2017 was acquired by Northrop Grumman.

In July 2019, the Air Force released its final request for proposals for the GBSD program, with an expected award date in the third quarter of 2020.

The addition of Aerojet to Northrop’s team guarantees that the nation’s only two manufacturers of large solid rocket motors will be part of the GBSD program. Other members of the Northrop Grumman team include BRPH, Clark Construction, Collins Aerospace, General Dynamics, Honeywell, L3Harris, Lockheed Martin, Parsons and Textron Systems.

In a statement on Monday, Aerojet said it will provide both a large solid rocket motor system and a post-boost propulsion system for GBSD.

Aerojet Rocketdyne’s GBSD work will be spread across three facilities: A manufacturing plant in Huntsville, Alabama; a newly built facility in Camden, Arkansas; and a precision post-boost propulsion technology plant in Canoga Park, California.

Northrop Grumman in August broke ground on a new facility, near Hill Air Force Base, Utah, to serve as a future headquarters for the GBSD program. The company said the program will employ over 10,000 people across the United States.

After bowing out of the competition as a prime contractor, Boeing proposed joining Northrop’s team but its offer was rejected, a Boeing spokesman said on Friday.

“In our discussions to date, Northrop Grumman has expressed that they are not interested in partnering with Boeing to form a best-of-industry GBSD team,” the spokesman said. “We are increasingly concerned that the Air Force’s deterrence mission and the nation’s security will be deprived of the best solution — a proven approach that leverages both companies’ technical strengths and decades of ICBM experience.”

The Air Force declined to comment on any of these developments. “While the Air Force is in source selection, we will not provide comments to preserve the integrity of the competitive process,” a spokesperson told SpaceNews.

Northrop Grumman is expected to submit its final proposal in December. Unless another bidder jumps in, it will end up being the only proposal, putting the Air Force in the uncomfortable position of having to negotiate a sole-source contract for such a large program.

The assistant secretary of the Air Force for acquisition, technology and logistics Will Roper told reporters at the Air Force Association’s symposium on Monday that it would be inappropriate for the government to weigh in until after the proposals are submitted and reviewed.

“We are still in source selection,” said Roper. “I can still receive proposals. I can’t presuppose what’s going to happen,” he added. “We’re open to teaming relationships. We just don’t want to dictate them. On the Air Force side, we’re still waiting for the proposal period to close and we’ll go from there.”