The Air Force has chosen Northrop Grumman Corp., maker of the B-2 stealth bomber, to build its next-generation bomber.

The highly classified, $80 billion project is designed to replace the aging B-2 bomber fleet with an information-age aircraft that eventually may be capable of flying without a pilot aboard.

The loser of the high-stakes bidding contest was a team formed by Boeing Co. and Lockheed Martin Corp.

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The B-2 stealth bombers have been flying for more than two decades, and will now finally be replaced.

'The long-range strike bomber will support America's defense strategy by forming the backbone of the Air Force's future strike and deterrent capabilities,' Defense Secretary Ash Carter said at a Pentagon news conference.

Carter said the new bomber will meet the nation's long-range strike aircraft needs for the next 50 years.

Wes Bush, chairman and chief executive of Falls Church, Virginia-based Northrop Grumman, said in a brief statement that his company will deliver on its promise to build a highly capable, affordable aircraft.

'Our team has the resources in place to execute this important program, and we're ready to get to work,' Bush said.

The announcement marks an important step in the Pentagon's broader plan to modernize the entire nuclear force — missile-toting submarines, land-based intercontinental ballistic missiles and long-range bombers.

The Congressional Budget Office estimates the cost at $348 billion over 10 years, and others have said it could approach $1 trillion over 30 years.

The Navy is committed to building a new fleet of 12 nuclear ballistic missile submarines to replace its 14 Trident submarines, and the Air Force is preparing to launch a program to build a modernized fleet of land-based ICBMs to replace its Minuteman 2 force.

It's unclear, however, how the Navy and Air Force will manage this in an era of shrinking budgets.

Air Force Secretary Deborah Lee James, accompanied by and Air Force Chief of Staff Gen. Mark Welsh III, announces that Northrop Grumman is awarded the US Air Force¿s next-generation long range strike bomber contract at a news conference at the Pentagon, Tuesday, Oct. 27, 2015. (AP Photo/Andrew Harnik)

Daryl Kimball, executive director of the Arms Control Association, said the administration is overreaching by investing so heavily in all three elements of the nuclear force.

WHAT WE KNOW ABOUT THE PLANE It was reported in July last year that the Air Force only generally described the platform, which it has designated as a top priority along with the F-35A Joint Strike Fighter and KC-46A tanker. 'The new bomber will be a long-range, air-refuelable, highly survivable aircraft with significant nuclear and conventional stand-off and direct-attack weapons payload,' the service said. 'The LRS-B will provide operational flexibility across a wide range of military operations.' Advertisement

'We believe the administration's redundant, all-of-the-above approach to rebuilding all of the major U.S. nuclear weapons delivery systems at levels beyond realistic deterrence requirements is unsustainable and will deplete resources from higher national security priorities,' Kimball said.

The new bomber is a high Air Force priority because the oldest ones in its fleet — the venerable B-52s — have far outlived their expected service life and even the newest — the B-2 stealth bombers — having been flying for more than two decades.

A third bomber, the B-1, is used heavily for conventional strikes, but no longer is certified for nuclear missions.

The Air Force said it will buy 100 of the new bombers at a newly calculated average cost of $564 million each.

The Northrop Grumman contract awarded Tuesday is for an initial set of 21 planes, plus $23.5 billion in engineering and development costs.

The estimated total cost to develop and purchase the full fleet would be $80 billion.

The Air Force said it has not picked a name or number designation for the new bomber.

Some have dubbed it 'B-3,' since it follows the B-2, which entered service in the late 1980s.

Industry news reports say that while the new plane's specific capabilities are highly secret, it likely will be equipped with high-tech communications gear and other electronics that would allow it to perform a variety of missions, not just dropping bombs.

THE HISTORY OF THE B-2 BOMBER The first operational aircraft, christened Spirit of Missouri, was delivered to Whiteman Air Force Base, Missouri, where the fleet is based, on 17 December 1993. Twenty one aircraft were built in the original B-2 fleet. The B-2 has demonstrated its capabilities in several combat scenarios, including Operation Allied Force in Kosovo; Operation Enduring Freedom in Afghanistan, Operation Iraqi Freedom, and most recently, in Libya, during Operation Odyssey Dawn. The B-2 is the only U.S. aircraft that combines long range, large payload and stealth in a single platform, giving it the ability to project air power anywhere in the world. It can fly 6,000 nautical miles unrefueled and 10,000 nautical miles with just one aerial refueling. With its ability to carry more than 20 tons of conventional and nuclear ordnance and deliver it precisely under any weather conditions, the B-2 also has the ability to change the outcome of a conflict with a single mission. The Air Force said it will buy 100 of the new bombers at a newly calculated average cost of $564 million each. Today, the fleet consists of 20 aircraft, following the loss, in February 2008, of the Spirit of Kansas, which crashed while taking off from Andersen Air Force Base, Guam, the only such incident in the B-2's more than 20 years of operation. Nineteen B-2s are currently based at Whiteman Air Force Base, Mo., home of the 509th Bomb Wing, while one aircraft is assigned to flight testing at Edwards AFB, Calif. to validate software and weapon systems upgrades. Advertisement

For the defense companies who sought the contract, the stakes were high.

Boeing has built most of the Air Force's bombers, including the B-52.

And it collaborated with Lockheed Martin on the F-22 stealth fighter.

Northrop Grumman built the B-2 bomber fleet, which was originally planned to include 132 planes but was scaled back to 21 at the end of the Cold War.

Loren Thompson, a vocal advocate of the new bomber program, says it is a key part of modernizing the military at a time of increased U.S. focus on China's growing might.

'The simple truth is that if the United States does not revitalize its dwindling fleet of heavy bombers, it probably cannot prevail in a war against China,' Thompson wrote earlier this month, citing what he called China's increasingly dense and agile air defenses.

He heads the Lexington Institute, which receives funding from major defense contractors.

The Obama administration has justified its support for a new long-range bomber by calling it vital to retaining U.S. military predominance.

In January, shortly before he left office, then-Defense Secretary Chuck Hagel visited a bomber base in Missouri to underscore his argument that a new bomber would help deter war and preserve the U.S. military's global reach.

Critics, however, question whether all three 'legs' of the U.S. nuclear triad — bombers, subs and land-based missiles — are necessary in the long run.

Each of the three has operated well beyond its intended life span, presenting an enormous challenge for the Pentagon at a time when it says budget pressures require it to scale back conventional forces.

The Pentagon also wants to buy a new air-launched nuclear-armed cruise missile at an estimated cost of $15 billion to $20 billion.

The Obama administration has justified its support for a new long-range bomber by calling it vital to retaining U.S. military predominance.