The Air Force Plans To Phase Out B-2 Bomber By 2030

In a continuing reshuffling of Department of Defense procurement under the Trump Administration, the Air Force now wants to retire the B-2 stealth bomber with the similar, but smaller and more modern B-21 stealth bomber, in just five years, rather than its previously planned 32 years from now. 

The current plan is to buy far more B-21s (at least 100) than the current fleet of B-2 bombers (which is under 20).

The B-21 is almost ready for prime time, having made its first flight in 2023,  and almost unprecedentedly for a project of this scale, is under budget. The lower cost is a result of accepting the limits of current technologies (which have still advanced significantly from the B-2) rather than trying to push beyond them, and of resisting the temptation to make the bomber supersonic or giving it air-to-air missile capabilities. It's smaller size also reduces the per bomber cost.

The B-21 will have a smaller bomb payload than the B-2, the B-1, or the B-52, despite having a similar global range. While the B-2 Bomber can carry two 30,000 pound GBU-57 MOP bunker buster bombs (the largest in U.S. service which it entered in 2011), a capability highlighted in a recent B-2 bomber strike on nuclear facilities in Iran, it will carry, at most, a single 22,000 pound "next generation penetrator" which can be delivered from a greater distance, from a platform that is more stealthy in the first place, and is more accurate, but has a smaller warhead. The 22,000 pound NGP is about the same size as the C-130 delivered MOAB GBU-43 bunker buster bomb.

Does this moderately degraded capability, that has been used only once and didn't exist until 2011 matter?

It would take about three B-21s to deliver the same amount of ordinance as one B-2. But the plan is to buy more than three times as many B-21s as the current fleet of B-2s. Even the 30,000 pound MOP bombs used in pairs in Iran did not, however, as briefly claimed after the strike, decisively destroy the deep nuclear facility bunkers there anyway.  

A tactical nuclear weapons, like the Cold War 51 pound Mk-54 Davey Crocket with a yield of 10-20 tons of TNT, could do the same, but would require crossing the threshold to using nuclear weapons. 

This would be a yield about 1,000 times smaller than the nuclear bombs dropped on Japan in World War II. The Hiroshima A-Bomb weighed 9,700 pounds (including 64 kg of Uranium-235) producing a 13-18 kiloton yield, and the Nagasaki A-Bomb weighed 10,300 pounds (including 6.2 kg of Plutonium-239) producing a 19-23 kiloton yield.

Realistically, one of the main missions of the B-21 would be to launch anti-ship missiles against a feared large Chinese fleet trying to invade Taiwan, and for that mission, a 22,000 pound bomb load is more the sufficient and quantity matters more than quality.

The Air Force has just announced an earlier retirement of the B-2 bomber by 2030. This is the second time that this has happened. This budget driven decision means that “…new B-21 must replace—and not be additive to—much of the existing bomber fleet. The Air Force had previously planned to operate the B-1 and B-52 until 2040, and the B-2 to 2058.” In addition, the Air Force has almost zeroed B-2 modernization.  

This may eliminate the U.S. ability to deliver the Massive Ordnance Penetrator (GBU-57/B or MOP) which is by far the most effective U.S. conventional weapon against hard and very deeply buried targets. The B-2 bomber is the only U.S. bomber cleared to deliver the MOP. It is also the only current U.S. bomber that can penetrate advanced air defenses. 

At about the same time, the Air Force accelerated the development of the Next Generation Penetrator (NGP) which would be carried by the new B-21. The NGP will be significantly lighter (no more 22,000 pounds) compared to the MOP’s (30,000 pounds). It will be superior to the MOP in some important respects. It will have a standoff capability, which is very important against advanced air defenses and substantially greater accuracy. However, it is unclear that it will be equal much less superior to the MOP in attacking and destroying large, hard and very deeply buried facilities such as Fordow in Iran. Moreover, at this point the NGP is untested. 

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The NGP has 8,000 pounds less weight available for high explosives which is only about 20% of the weight of the MOP. This is usual for penetrators which have to be built very heavy and strong to survive rock and reinforced concrete penetration. In addition, a significant part of the NGP weight will be the rocket motor which will further reduce the weight available for high explosives. Thus, it is possible that the NGP will be less effective than the MOP against large, hard and very deeply buried targets such as Fordow.

The B-21 bomber, the world’s first sixth generation aircraft, is an enormous improvement over the B-2 in most respects. It clearly has much greater stealth. The Air Force has characterized its stealth level as “extremely low observable.” Reportedly, its radar cross section has been reduced from .1 square meter in the B-2 to either .0001 or .0004 in the B-21. This would greatly increase its ability to penetrate advanced air defenses. Its stealth is much more robust than the much older technology which was used in the B-2. This will substantially increase bomber combat availability. The aircraft carries advanced sensors and electronic warfare capabilities. The B-21 has an open systems architecture which will facilitate future upgrades. Northrop Gruman has done an incredibly good job in bringing the B-21 into existence actually under budget. When the contract award was announced in 2015, many doubted whether this was possible.

However, the B-21 was designed in a period of defense budget starvation under the Obama Administration. It was deliberately made less capable than it could have been. Retired Air Force Chief of Staff General Norton Schwartz, wrote in his memoires that the Next Generation Bomber (NGB, sometimes called the 2018 bomber) “‘…had grown too big’ and was carrying too many missions and requirements. It was to have an air-to-air missile capability for self defense.” This original concept for the NGB was de facto terminated in 2008 although it was described as a delay. The need to minimize B-21 costs (no more than $550 million per aircraft in 2010 dollars) resulted in an adoption of a low technical risk strategy, a smaller bomber, no possibility of it ever having a supersonic capability and a production equipment limitation on the possible production rate. Some analysts believe that stealth must be combined with supersonic speed to deal with the long-term projected threat environment and that the number of penetrating bombers must be doubled.

The size and weight of a bomber has a significant impact on its costs. For most missions the B-21s bomb load is sufficient. However, good capabilities against hard and very deeply buried facilities require the maximum practical bomb load. 

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It is clear that the B-21 is significantly smaller and lighter than the B-2. (The B-2 itself is also substantially lighter and smaller than the other U.S. heavy bombers, the B-52s and B-1s). According to noted aviation journalist Bill Sweetman, “The B-21’s resemblance to the original B-2 bomber design is close, but it is a smaller aircraft, with a wingspan estimated at 132 ft. compared with the B-2’s 172 ft., and is approximately half the empty weight.” If so, this would make it an advanced medium bomber with intercontinental range. The payload of the B-21 is clearly limited compared to the bombers it is replacing. Sweetman and a number of other aerospace journalists have reported that the bomb load of the B-21 is about 20,000 pounds. Christian Orr, editor of the National Security Journal, writes, “If Mr. Sweetman’s estimates are accurate, that would cast serious doubt upon the newer warbird’s ability to carry the 30,000-lb. (14,000 kg) GBU-57 Massive Ordnance Penetrator (MOP) bomb immortalized by its usage in the Midnight Hammer strikes.”

There are many reports that the B-21 can carry a single MOP, but this appears to largely be speculation. There is no official confirmation of this and it appears unlikely. If the weapons load is limited to about 20,000 pounds, it cannot carry even a single MOP. There are reports of higher bomb load numbers for the B-21 but the limitation of the weight of the NGP to 22,000 pounds suggests that the lower estimates of the B-2 bomb load are more accurate.

Even if the B-21s were able to carry the MOP, they certainly would be unable to carry more than one compared to two on the B-2. The MOP was originally designed to be used two at a time to maximize the probability of target destruction.

From here. 

In other military procurement news, the U.S. Navy is extending the life of three cruisers from 2026 to 2030. The U.S. Army is adding four new Patriot Missile battalions. And, the U.S. Marine Corps has ordered 44 of its new air defense systems for about $32.52 million:

The MRIC (Medium-Range Intercept Capability) is a mobile and modular air defense system developed specifically for the U.S. Marine Corps to provide a medium-range intercept capability against a wide array of aerial threats. Designed to operate in expeditionary and contested environments, MRIC fills a critical capability gap between short-range systems like the Stinger missile and long-range assets such as Patriot. The system is capable of intercepting cruise missiles, unmanned aerial vehicles (UAVs), and indirect fire threats such as rockets, artillery shells, and mortars.