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Smart Bombs: Military, Defense and National Security

B-21 Raider Stealth Bomber: The Definitive Guide

B-21. Image Credit: Northrop Grumman
B-21. Image Credit: Northrop Grumman

Unveiling of America’s New B-21 Raider Stealth Bomber Draws Nigh—Here’s What To Expect: On December 2, defense giant Northrop-Grumman plans to finally unveil one of the United State’s most expensive and lethal new weapon systems of the 21st-century—a next-generation nuclear-capable stealth bomber designated the B-21 Raider.

We know from multiple publicized concept renderings that the B-21 resembles a smaller version of the flying wing aircraft it’s meant to succeed—the U.S. Air Force’s B-2 Spirit stealth bomber, of which just 21 were built at a staggering unit-cost of a half-billion dollars apiece (one billion in 2022 dollars).

However, the Air Force plans to acquire many more B-21—at least 100, though the services would like 145 or 174 bombers given the many roles it’s expected to perform beyond nuclear strike.

Since a contract was awarded in October 2015, Northrop Grumman has been assembling six B-21 airframes under a veil of secrecy at the Air Force’s ‘black project’ Plant 42 facility in the Mojave Desert near Palmdale, California. The first assembled prototype is currently undergoing structural calibration testing. From there, it will move on to the engine and taxi test, leading to a first flight in 2023 (delayed from 2021), with initial operational capability expected as soon as 2025-2027.

B-21: The Strategic Bomber Future

Large, expensive strategic bombers designed to strike targets across the globe are making a comeback due to intensifying strategic competition (particularly regarding nuclear weapons) between the United States, China, and Russia.

Furthermore, China is increasingly capable of unleashing powerful conventional ballistic missiles strikes on U.S. fighter bases and naval taskforces in the Western Pacific. In that context, long-range bombers that can launch raids from Hawaii or North America are growing more desirable.

Currently, the Air Force operates three strategic bombers: 76 venerable B-52s, 45 faster B-1B Lancers (no longer wired to deliver nuclear weapons), and 20 stealthy B-2s—the only type deemed adequately survivable to penetrate active enemy air defenses.

The service will use B-52s for many more decades to deliver long-distance cruise/hypersonic missiles. However, the B-21 is intended to replace the B-1 and eventually the B-2 in the 2030s, equipping bomber squadrons at Dyess, Ellsworth, and Whiteman air force bases in Texas, South Dakota, and Missouri, respectively. Ellsworth will also host the first Formal Training Unit, while Edwards AFB in California will have a B-21 test unit (420th Flight Test Squadron), and Tinkers in Oklahoma will serve as a depot. New B-21 hangars and facilities will cost roughly $1 billion.

B-21 Specs

Few specifics regarding the B-21 have been released. Official concept art reveals a cleaner, more straightforward profile with a pointier nose than the Spirit’s otherwise similar profile but clearly smaller than the B-2. It’s generally believed to have a lower maximum payload in the range 15-20 tons, to fly at similar subsonic speeds and maximum range (6,000+ miles) on internal fuel, which in practice is routinely augmented by aerial refueling.

Though the Raider has a crew of two, the Air Force initially claimed it would be “designed to accommodate manned or unmanned operations”—meaning it could be operated like a drone if desired. However, the Raider reportedly doesn’t yet have AI integrated, so it sounds like unmanned capability will be phased in later.

More Affordable (Relatively)

Northrop-Grumman’s design won the Air Force’s Long Range Strike-Bomber (LRS-B) competition due to lower promised costs. The design reportedly integrates mature technologies based on the company’s experience developing and upgrading the B-2 and possibly the secrecy-shrouded RQ-180 drone.

The B-21 was pegged for a unit cost of $553 million in 2010 dollars (ie. already around $750,000 by 2022!). Still, only an after engineering/development cycle is projected to cost $21.4 billion, for which the actual total remains unclear. That may seem just as pricy as the B-2 but it comes to a significant decrease when inflation is factored in.

To be sure, downsizing the B-2 order from 132 aircraft to just 21 was responsible for skyrocketing unit price—and the B-21’s cost is surely premised on procuring at least 100. However, congressional overseers have generally praised its surprising success remaining on cost and on schedule, unlike the F-35 stealth fighter’s notoriously rocky development. Reportedly, digital design tools have allowed flaws to be fixed in just 1-2 months instead of requiring an entire year.

Even more importantly, the B-21 is designed for lower flight-hour/maintenance costs than the B-2, which uses 1980s-era radar absorbent materials (RAM), requiring extremely expensive and time-consuming maintenance, and preventing practical use for routine operations. The Air Force needs the B-21 to be affordable for a broader range of missions.

More durable ‘baked-in’ RAM should reduce B-21 maintenance costs considerably. Air Force leaders also suggest using Pratt & Whitney F135 turbofans, already mass-produced for F-35 stealth fighters will significantly reduce production and maintenance costs. And just two of the higher-thrust F135s are believed sufficient to propel the smaller B-21 instead of the B-2’s four F118 engines. That said, designing nested engine inlets balancing stealth and airflow (for thrust) has reportedly proven challenging.

Time will tell if the low drama associated with the program can be sustained as it transitions to greater public scrutiny and oversight. In 2020 a Congressional Budget Office report estimated a B-21, combined with eight nuclear LRSO missiles and two warhead-less spares, would cost $40 million annually to sustain—compared to over $41 million for a B-2 without counting munitions.

Stealthier and Higher-flying

Modern integrated air defense systems (IADS) have become so lethal it’s not considered possible for bombers to fly fast or high enough to reliably evade them. That leaves just two options for hitting targets shielded by active, modern IADS: releasing long-range missiles from aforementioned B-52-style ‘missile trucks’ or using aircraft stealthy enough to (mostly) evade detection. That’s the concept underpinning the B-2 and the forthcoming B-21.

But stealth aircraft aren’t all equally low-observable. They can be detected (but not targeted) by low-frequency band radars at a distance or short range, by electro-optical infrared sensors, and powerful X-Band radars like the Irbis-E on Russia’s Su-35S fighter.

The B-2 retains a larger radar cross-section than the later F-22 and F-35—while the B-21 has been implied to be stealthier than those fighters. That will likely be achieved by further optimizing the engine inlets and outlets (a common Achille’s heel in stealth aircraft) and wings, as well as using improved RAM.

Air & Space Forces magazine’s John Tirpak observes the B-21’s simpler wing geometry than the B-2 makes it optimized for superior high-altitude performance, where thinner air produces less friction allowing higher speed and range. But that exposes aircraft more to hostile radars. That suggests the Air Force is confident the B-21’s reduced radar signature can withstand greater scrutiny.

The B-21 Raider is designed with an open systems architecture, enabling rapid insertion of mature technologies and allowing the aircraft to be effective as threats evolve. The bomber was designed up front for supportability and maintainability-based upon decades of lessons learned and best practices from prior aircraft programs-to improve long-term affordability and outcomes in operations and sustainment. The B-21 first flight is anticipated to take place in calendar year 2023. (U.S. Air Force photo) The B-21 Raider is designed with an open systems architecture, enabling rapid insertion of mature technologies and allowing the aircraft to be effective as threats evolve. The bomber was designed up front for supportability and maintainability-based upon decades of lessons learned and best practices from prior aircraft programs-to improve long-term affordability and outcomes in operations and sustainment. The B-21 first flight is anticipated to take place in calendar year 2023. (U.S. Air Force photo)

Northrop-Grumman will also likely seek further reductions to heat signature and even electromagnetic emissions. The B-21’s sensor suite will indeed feature a low-probability of intercept (LPI) active electronically scanned array radar designed for jam-resistant, high-resolution scanning of aerial threats and ground targets without betraying the aircraft’s presence.

A Bomber That’s Also a Spy Plane, Drone Commander and…a Fighter?

The B-21,  like the B-2, will play an important role in the U.S.’s air-based nuclear deterrence due to their potential to unleash a high volume of conventional or nuclear weapons while within hostile airspace with less warning than would come from a ballistic missile. Early in a major conflict, they would likely target enemy WMD assets, air defenses, airbases, command-and-control hubs, and key logistical infrastructure and depots.

The B-21 can employ more affordable short-range weapons against most targets. But against especially well-defended ones, it can lob standoff-range JASSM cruise missiles and JSOW glide bombs.

The B-21 will feature a “broad mix of stand-off and direct-attack munitions.”
  Warhead Yield Max on B-2* Range Guidance Cost
Nuclear weapons
B-61-12 nuclear glide bomb .3, 1.5, 10 or 50 kt. 16 Several miles INS + GPS $28 million
AGM-181 LRSO** cruise missile Possibly 5 or 150 kt 8 on B-21? 1,500 miles+   $10 million (estimated)
Standoff Range Conventional Weapons
AGM-158A/B/B2 JASSM cruise missile 1,000 lb. 16 230/575/1,200 miles GPS + Infrared


/$1.5 million

AGM-158C LRASM anti-ship missile*** 1,000 lb. 16 ~350 miles GPS, Infrared,  radar-homing $3 million
AGM-154A JSOW glide bomb 145 bomblets 16 80 miles (from high altitude) GPS $282,000
AGM-154C JSOW glide bomb 500-lb shaped charge 16 80 miles (from high altitude) GPS + infrared $719,000
Short Range Conventional Weapons
JDAM Glide Bomb 500/2,000 lb. 80/16 17 miles (high alt.) GPS ~$30,000
GBU-57 Massive Ordnance Penetrator 30,000 lb. 2 Gravity GPS $3.5 million
Gravity Frag/Cluster Bombs 500 lb./750 lb./ 2,000 lb. 80/36/16 Gravity None $2,000-3,000

Key: kt= kiloton (one thousand pounds of TNT)  mt= megaton (one million pounds of TNT)

* B-21 likely carries at least half as many munitions as the larger B-2.  ** In development *** On B-1, not B-2.  Note: Infrared-guided weapons can hit moving targets.





However, the Air Force has a broader mission set in mind, repeatedly emphasizing the B-21 is just one element in a ‘family of systems’ likely including modular payloads and drones. Reportedly additional roles include “…including Intelligence, Surveillance and Reconnaissance [ISR], electronic attack, communication and other capabilities.”

Flexibility will be intrinsic to the B-21’s open-architecture computer system, which will allow rapid digital updates to the aircraft classifying newly identified threats, further networking its comms and sensors with friendlies, and integrating new weapons or alternative payloads.

Indeed, an Air Force general claims new weapons will be integrated in one-tenth the time necessary for the B-2, meaning fewer ‘Block’-style depot/manufacturer modernizations will be required. However, as the service plans to operate the B-21 late into the 21st century, the airframe likely is built to support decades of modernization with spare capacity and apertures for stealthy conformal attachments.

Like the F-35 stealth fighter, the B-21 will undoubtedly have multiple robust sensors—radar, electro-optical, electromagnetic—which can be used in an intelligence-surveillance-reconnaissance capacity spying on the position, communications, and electromagnetic activity of adversaries. It could then relay data to friendly warships, strike aircraft or ground-based missile units via networked datalinks.

But the Raider will be able to embark on longer distance, and endurance missions than a short-ranged F-35 could do. It might also leverage that endurance as a survivable Battlefield Airborne Communication Node (BACN) interconnecting communications and sensor data from forward-deployed ground forces, or in an electronic attack role suppressing adversary radar and communication systems with powerful jammers.

B-21 Raider. Industry Handout.

The Air Force has also stated the B-21 will serve as a drone control platform. The service even studied developing specialized ‘drone wingmen’ to accompany B-21s into combat but concluded the cost was too high to be practical. However, the B-21 will not lack for armed and unarmed drones it could work in tandem with such as the Kratos XQ-58 Valkyire ‘loyal wingman’, the ADM-160 miniature air-launched decoy, the stealthier Boeing MQ-28 Ghost Bat, and, it is rumored Northrop Grumman’s own mysterious RQ-180 stealth drone.

The B-21’s combination of stealth, endurance, weapons, and sensors could also be used for search-and-destroy missions targeting high-value mobile assets like truck-mounted ballistic missiles or warships at sea (an anti-ship role it’s likely to inherit from the B-1 bomber.)

It’s also believed the B-21, unlike the B-2, may be compatible with air-to-air weapons like beyond-visual range AIM-120 and forthcoming AIM-260 missiles, giving it a shot at dispatching or driving away one or two fighters in self-defense. But some analysts further theorize the B-21 could contribute to air superiority missions slinging large, very long-range air-to-air missiles at enemy warplanes over 200 miles away. Lacking a fighter’s agility, a B-21 would be at big disadvantage up close—but could surprise attack enemies from over a hundred miles away who can’t detect it and shoot back. This seems most viable for intercepting slower bombers, or making distant missile shots supporting a forward screen of agile fighters.

B-21 Raider Stealth Bomber

Construction of a B-21 Raider Environmental Protection Shelter prototype is completed at Ellsworth Air Force Base, S.D., Feb. 26, 2021. Ellsworth AFB was selected as the test site for the B-21 EPS as it provides the most extreme and diverse weather conditions to test the temporary structures. The testing for the EPS prototypes at Ellsworth AFB does not interfere with Air Force compliance to the National Environmental Protection Act/Environmental Impact Statement preparation for the first B-21 Main Operating Base. (U.S. Air Force photo by Airman First Class Quentin Marx)

B-21 Raider Stealth Bomber

Earlier artist rendering.
Image: U.S. Air Force

The B-21 Raider and the Future of U.S. air power

The Air Force views the Raider as its best-suited platform for potential conflict with China over the sprawling expanse of the Pacific Ocean. But whether the service gets the larger B-21 fleet it wants will depend in part on whether Northrop-Grumman can continue to develop and build B-21s with minimal cost overruns and controversy.

Meanwhile, China may soon unveil its own B-2-like H-20 stealth bomber. Russia’s PAK-DA stealth bomber is also in development but is likely to take much longer to enter into production and service. However, Russia’s war in Ukraine has highlighted the risks of relying entirely on expensive cruise missiles for deep strikes—with Moscow having mostly expended its arsenal of these.

For now, there remains much anticipation that the B-21’s unveiling this December will finally answer long outstanding interest regarding its performance, capabilities, and innovations.

B-21 and B-2 Bomber Pictures From the Past Few Years


A B-2 Spirit assigned to Whiteman Air Force Base, Mo., prepares to receive fuel from a KC-135 Stratotanker, Feb 7, 2021. A B-2 Spirit performed alongside a B-1B Lancer and a B-52 Stratofortress for the Super Bowl LV flyover on Feb. 7, 2021. (U.S. Air Force photo by Airman 1st Class David D. McLoney)

B-2 Spirit stealth

191209-N-HG846-2001 NORFOLK,Va. (Dec. 9, 2019) This poster is designed to communicate the aircraft specifications of the B2 Spirit Stealth Bomber. The B2 bomber was introduced on Jan. 1, 1997 by the Northrop Corporation.


B-21 Raider artist rendering. Image Credit: Creative Commons.

B-21 Raider

B-21 Raider Stealth Bomber. Image Credit: Creative Commons.

Sébastien Roblin writes on the technical, historical, and political aspects of international security and conflict for publications including The National InterestNBC, War is Boring and 19FortyFive, where he is Defense-in-Depth editor. He holds a Master’s degree from Georgetown University and served with the Peace Corps in China.  You can follow his articles on Twitter.

Written By

Sebastien Roblin writes on the technical, historical, and political aspects of international security and conflict for publications including the 19FortyFive, The National Interest, NBC News,, and War is Boring. He holds a Master’s degree from Georgetown University and served with the Peace Corps in China.