The Pentagon on Tuesday picked the plane that will be a core component of its fleet for the next half century, and it will be built by Northrop Grumman.

In one of the most hotly anticipated military contract announcements in years, the Air Force selected the Virginia-based defense firm to build the first 21 long-range strike bombers in a contract estimated to total $80 billion. Northrop Grumman won out over a joint bid from Boeing and Lockheed Martin. The planes won’t debut until 2025, but when they do, the Air Force says they’ll be able to fly undetected through Russia and China with the capability of launching an airstrike—either conventional or nuclear—from the continental United States to any point on the globe.

“Building this bomber is a strategic investment in the next 50 years,” Defense Secretary Ash Carter said in an announcement that was made after markets closed, in an indication of how important it was for the defense industry. The new long-range strike bomber, he said, would form “the backbone of our future strike and deterrent capabilities.”

While the Pentagon is initially buying 21 planes, it is planning for an eventual fleet of 100. Each of the first bombers will cost $564 million, according to independent cost estimates.

The announcement had been a long time coming.

For more than a decade, the Air Force has been looking for a new plane that can eventually replace the B-1s, which debuted in the 1980s, the B-2s, which date to the ‘90s, and in particular the B-52s, which have flown three generations of U.S. airmen. As William LaPlante, the assistant secretary for acquisitions, told reporters last week, the Air Force is aware of grandfathers, fathers, and sons who have flown the very same aircraft, decades apart. “They’re used today operationally,” he said. And they will be in use until 2040, more than a decade after the Pentagon hopes to have its new fleet of bombers.

While the current fleet remains useful, the Air Force wants a bomber that can evade the advancing air defenses of Russia and China—if ever the need arises. The long-range bomber would act as a deterrent against actions designed to keep U.S. forces out of a designated area—what the military calls “anti-access aerial denial.”

“I’m talking about our ability to put effects on targets anywhere in the world,” LaPlante said in his briefing last week. “That’s being challenged. It’s degrading.” And although the military is planning more than a decade into the future, it is already seeing evidence of that challenge as the U.S. fights the Islamic State—and eyes Russian military intervention—in Syria. "We need to provide national command authorities an option to strike any target, any time, and that's what this platform is designed to be able to provide,” said Lieutenant General Arnold Bunch, LaPlante’s deputy.

The Defense Department began planning for a new bomber contract in 2004, but former Defense Secretary Robert Gates put the project on hold in 2009 because of money concerns. The long-delayed, over-budget F-35 procurement played a role, as did concerns from Capitol Hill. Officials had previously announced that the planes would be built using existing technology in a bid to keep costs down and make it easier to upgrade the fleet in future years. In another important departure from previous contracts, the Pentagon plans to open the competition for future parts and upgrades to other firms, a move designed to maximize affordability and speed the production process.

The planning process had also been cloaked in secrecy. The acquisition was run out of the Pentagon’s Rapid Capabilities Office, which is used for urgent and classified projects. Officials wouldn’t disclose many details about the plane on Tuesday, nor did the Defense Department release an image of what it would look like.