The U.S. Government Accountability Office has dismissed Lockheed Martin and Boeing's protest of the Long Range Strike Bomber contract going to Northrop Grumman.

The U.S. Air Force contract for the design of the next-generation bomber was awarded to Northrop Grumman in October 2015, beating a joint venture between Lockheed Martin and Boeing. The GAO's dismissal of the protest allows Northrop Grumman to resume work on the contract.

"Northrop Grumman is pleased that the U.S. Government Accountability Office (GAO) has denied Boeing's protest and reaffirmed the Air Force's decision to award Northrop Grumman the Long-Range Strike Bomber (LRS-B) contract," Northrop Grumman strategic communications vice president Randy Belote said in a statement. "This confirms that the U.S. Air Force conducted an extraordinarily thorough selection process and selected the most capable and affordable solution."

Lockheed Martin and Boeing filed protests with the GAO shortly after the contract award was announced in November 2015, claiming the Air Force made a flawed decision by not properly evaluating the costs or risks of each proposal.

"We continue to believe that our offering represents the best solution for the Air Force and the Nation, and that the government's selection process was fundamentally and irreparably flawed," Boeing wrote in a statement responding to the protest dismissal.

The LRS-B contract has an estimated $80 billion value over the life of the program. The bomber will be designed to carry thermonuclear weapons, and equip new technologies as they become available.