U.S. Secretary of Defense Lloyd Austin used glowing terms to describe the B-21 Raider, the stealth bomber under development for the U.S. Air Force. According to Austin, the bomber will be durable, stealthy, nuclear-capable, and fit to gather intel. It will control drones and operate across a very long range.
“You know, the B-21 looks imposing,” Austin told an audience during the B-21’s unveiling in December. “But what’s under the frame and the space-age coatings is even more impressive.”
Austin probably kept his remarks general by design. The cutting-edge program is almost entirely “black,” meaning it is not available to the public for obvious security reasons. Still, he did offer a critical window into key areas of emphasis for the new bomber. Members of Congress, analysts at think tanks, and even some Air Force senior leaders have suggested the planned fleet size for the B-21 should be much larger than the planned 100 planes — it should more than double, reaching 225 planes or higher. The first several B-21s are already under construction and slated to take to the sky in coming months.
Senior leaders have said very little about the bomber in the years it has been under development, but Austin’s remarks indicate a few points of technological focus for the platform. Further, Pentagon and Air Force developers have indicated that the B-21 will likely be capable of flying unmanned, and it will probably control small fleets of mini-drone loyal wingman platforms. These will extend the B-21’s reach, allowing it to blanket areas with surveillance, test enemy air defenses, and support a multi-domain network of interconnected nodes throughout multi-domain formations.
We have also heard that the B-21 incorporates paradigm-changing dimensions of stealth technology and, as Austin put it, incorporates “50 years of advances in low-observable technology.”
Enemy Air Defenses
“Even the most sophisticated air-defense systems will struggle to detect a B-21 in the sky,” Austin said at the unveiling of the platform. While particulars about the B-21’s stealth properties are unavailable, there are some general characteristics that are fundamental to achieving stealth and eluding enemy air defenses and tracking systems. The most noticeable element of stealth is often an aircraft’s configuration.
The fewer sharp edges, protruding structures, or angled contours on an aircraft, the stealthier it is. The B-21 is rounded, horizontal, and sleek, and it is built with a blended wing-body formation. This shape greatly reduces the ability of electromagnetic pings from ground-based radar to deliver a return signal or a rendering. A radar’s electromagnetic signals determine the shape, size, and even speed of an object by bouncing electrons off a surface and analyzing the return signal to obtain a rendering of an object, but stealth aircraft are designed to elude both lower-frequency surveillance radar and higher-frequency engagement or targeting radar technologies. Stealthy aircraft, for example, are engineered to resemble a small bird on enemy radar.
To the naked eye, the B-21 simply looks a bit stealthier than the B-2, as evidenced by the rounded,more “blended-in” engine inlets. The B-2’s engine inlets are on top of the fuselage like the B-21’s, but they are boxier — more rectangular and angled than the smoother blended curves of the B-21’s inlets. Reducing the angles should generate a much smaller, less detailed radar return signature, making it harder for enemy ground systems to sort out what an object in the sky might be.
Sticking to exterior attributes, stealth aircraft are regularly covered in radar absorbing materials. The nature of such materials is highly secret, but they are designed to absorb the electromagnetic pings from ground radar.
It is likely that the B-21 uses new generations of stealth coating materials. This is important, because ground-based air defense radar technologies have become increasingly sensitive and precise. Ground radar is effective at longer ranges, is better networked through digital processing, and operates on a wider range of frequencies than ever before. Technologies exhibited by Russian S-400 and Chinese HQ-9 air defenses have vastly increased the risk to stealth platforms in recent years, inspiring the need for a new generation of low-observable technology.
The aim with the B-21, as with its predecessor, the B-2, is to enter, occupy and attack an enemy area without the enemy having a clear idea that anything is there at all. This ability is called broadband stealth, and the aim is to remain entirely clandestine.
Many properties contributing to an aircraft’s stealth characteristics are related to temperature. Stealth aircraft are known for having internally buried, or “embedded” engines to decrease and regulate an aircraft’s thermal signature. The closer an aircraft’s temperature is to that of the surrounding atmosphere, the less detectable it will be to infrared or temperature-sensitive ground sensors. Most stealth aircraft are engineered with special exhaust areas to control, monitor, and regulate the heat signature.
Finally, speed and altitude can enhance stealth. An aircraft at higher altitude is less likely to generate a clear rendering. Several technologies can increase an aircraft’s altitude ceiling, the most significant of which is probably sensing. If targeting sensors evolve to deliver a precise, high-fidelity signal to the aircraft from much higher altitudes, a stealth bomber can attack from much farther away.
B-21 Can Attack “Anywhere in the World”
Apart from the somewhat mysterious and unknown technologies that may enable a new generation of stealth, there are other reasons why Air Force leaders claim the new bomber will be able to place “any target at risk…anywhere in the world…..at any time.” Former Air Force Military Deputy Ret. Gen. Arnold Bunch mentioned this to Warrior many years ago — as far back as 2015 — and sure enough, Austin used similar language at the unveiling of the aircraft in December 2022.
“Let’s talk about the B-21’s range. No other long-range bomber can match its efficiency. It won’t need to be based in-theater. It won’t need logistical support to hold any target at risk,” Austin said.
During Operation Enduring Freedom over Afghanistan, B-2s became famous for making 44-hour operational sorties from Whiteman Air Force Base in Missouri all the way to Diego Garcia off the coast of India. This was a staging area from which the B-2s could launch missions against Taliban targets in Afghanistan.
Austin’s comment suggests the B-21 might have even greater range, meaning it can hold targets at risk anywhere in the world without needing to land. Available specs say a B-2 can fly 6,000 miles without needing to refuel, and the B-21 should exceed this reach. Range matters, not only for allowing aircraft to reach and attack distant enemy locations, but also in terms of dwell time. Longer range for a bomber means it can spend more time retargeting, adjusting to new intelligence, or searching for new targets without needing to return. This maximizes mission efficiency and reduces risk by lowering the number of needed missions. If supported by networking, it enables a bomber to respond in near-real time to changing threat information.
When it comes to that threat information, Austin also made it clear that the bomber will be multifunctional, meaning it will perform a wide range of missions beyond simply attacking or dropping bombs.
“It can handle anything from gathering intel to battle management to integrating with our allies and partners. And it will work seamlessly across domains, and theaters, and across the joint force,” Austin said.
By referring to intel and battle management, Austin made clear that the mission envelope for the B-21 will expand to include operating as a surveillance and intel node in the sky, gathering, processing, and transmitting time-sensitive war detail across multiple domains as part of a joint, multinational war operation.
Not surprisingly, very little information is available when it comes to the B-21’s weapons, but Austin did of course say it would be nuclear-capable as an integral part of the air leg of the nuclear deterrence triad. Senior Pentagon and Air Force leaders have also said the B-21 will likely be armed with long-range, air-launched cruise missiles, some of which could be nuclear-capable as well.
Kris Osborn is the Military Affairs Editor of 19FortyFive and President of Warrior Maven – Center for Military Modernization. Osborn previously served at the Pentagon as a Highly Qualified Expert with the Office of the Assistant Secretary of the Army—Acquisition, Logistics & Technology. Osborn has also worked as an anchor and on-air military specialist at national TV networks. He has appeared as a guest military expert on Fox News, MSNBC, The Military Channel, and The History Channel. He also has a Masters Degree in Comparative Literature from Columbia University.