The B-21 Raider's Critical Numbers Game.

• Author: Magnuson, Stew

The Air Force's B-21 Raider is designed to prevail against robust air defenses, deliver precision weapons on targets deep in enemy territory and return its two-man crew safely home.

But a bigger challenge as the program moves forward is whether the program can prevail in the yearly Defense Department battles over funding, keep its costs down and deliver the 100 aircraft the Air Force says it needs to maintain its edge over adversaries.

Air Force and Northrop Grumman officials at the B-21 roll-out ceremony in Palmdale, California, gave an upbeat assessment of not only the program's current costs, but how much funding it will require in the future.

Andrew Hunter, Air Force undersecretary for acquisition, technology and logistics, told reporters that so far, the program is "tracking well" on cost and schedule.

"One of the key aspects of this program is that we had a very firm cost target. That is a requirement for the program. And that will support our ability to deliver the number of aircraft we need to truly perform the missions that are outlined in the National Defense Strategy," he said.

The program kicked off 12 years ago with a requirement for 100 aircraft at a cost of $550 million each in 2010 dollars. Officials say the current per-aircraft cost is classified, but with a cumulative rate of inflation of 36.7 percent, that comes to $751 million per aircraft in 2022 dollars.

Maintaining steady numbers is critical to the Air Force as it divvies up funding for its own needs and engages in the yearly food fight with the Navy, Army and Marine Corps for finite taxpayer dollars to fund their priorities.

And there will be many budget battles in the coming years that will put pressure on the B-21 program.

Jet fighters have their own advocates within the Air Force, which is trying to build out its F-35A Lightning II, field the F-15EX, maintain its legacy fleets and develop a sixth-generation Next Generation Air Dominance fighter.

Bombers are part of the nuclear triad along with submarines and intercontinental ballistic missiles.

All three are being modernized and replaced with completely new systems over the next decade, with the Air Force in charge of the Ground-Based Nuclear Deterrent ICBMs as well as upgrading the nuclear command and control infrastructure that ties the triad together. The Navy is building 12 Columbia-class ballistic missile submarines.

Meanwhile, the Navy's ultimate goal is to operate as many as 372 ships, the Army has a big...