While the US mulls acquiring more of its next-gen B-21 bombers, fast-moving technological advancements could make the type obsolete upon delivery.
This month, The Warzone reported that US Air Force (USAF) Chief of Staff General David Allvin has hinted that the service is considering purchasing more than the 100 B-21s currently planned.
Allvin stated that the B-21 is the future of the bomber force and that the number of B-21s is expected to reach 100 by the mid-2030s and beyond.
The USAF is exploring options to supplement or replace B-21 production while also planning to fly updated B-52s equipped with the Rapid Dragon palletized munition system as an inexpensive means of creating long-lasting, low-complexity stand-off strike platforms.
It is also considering buying all 100 B-21s despite cost issues, which are coming down after negotiations with Northrup Grumman. However, the threat environment that informed the B-21’s design a decade ago has significantly changed.
The B-21 is a member of the Long Range Stand-Off (LRSO) family of systems and can be used for future variations or derivatives along with the AGM-181A LRSO stealthy nuclear-armed cruise missile and other advanced systems such as munitions, sensors, electronic warfare packages and communications systems.
However, The Warzone says that acquiring additional B-21s contradicts evolving trends in aircraft procurement and capabilities. The bomber mission is changing due to survivability demands, evolving integrated air defense networks and longer-range and more capable counter-air munitions.
It also states the importance of using cost-effective, quickly designed and readily deployable stand-off systems is increasing on the battlefield. At the same time, the B-21 may be the last new USAF bomber.
While strategic bombers have been the long arm of US airpower during the 20th and early 21st centuries, technological advances may force a rethink of stealth bombers’ role in increasingly transparent aerial battlefields.
In an August 2022 Air University article, Mel Deaile mentions that stealth technology in aircraft has advanced since 2001, emphasizing the importance of bombing tactics that leverage low-observable characteristics.
Deaile also expounds on the role of the bomber over the past 30 years, noting the shift from multiple bombers attacking a single target to one bomber hitting multiple targets with precision.
However, he points out that China’s growing airpower poses a challenge to US strategic bombing capabilities, noting that the People’s Liberation Army – Air Force (PLA-AF) is the third largest air force in the world. As of October 2023, the PLA-AF has 1,900 fighters and has operationally fielded its J-20 stealth fighter, whose numbers are expected to grow in the coming years.
Deaile also points out that China has a robust and redundant integrated air defense system (IADS), operating radars, fighters and surface-to-air missile (SAM) systems that can reach up to 300 nautical miles offshore to defend against an impending attack.
China has made considerable efforts to defeat US stealth aircraft such as the B-21, leveraging AI and more advanced sensors. In December 2023, Asia Times reported that China had simulated shooting down a B-21 using new stealth aircraft, advanced radars and hypersonic missiles.
The simulation showcased new technologies, such as stealth aircraft with “conformal skin” that detects heat and electric signals, unmanned wingman drones and hypersonic missiles with adjustable solid-fuel pulse engines. It also emphasized the potential of AI in air-to-air combat, with decision-making shifting rapidly between pilots, drones and missiles.
In addition, China has reportedly developed a small and discreet anti-stealth radar that can be quickly and quietly placed on rooftops, contrasting with traditional systems that need large antennas to detect stealth aircraft.
Chinese engineers have also reportedly designed a compact infrared search-and-track (IRST) system based on medium-wave infrared technology capable of detecting the signature of fast-moving aircraft from considerable distances. The device can identify the aircraft’s outline, rotors, tail and number of engines from the infrared spectrum image.
Furthermore, the South China Morning Post (SCMP) reported this month that Chinese researchers have developed a method to increase an F-22’s radar signature up to 60,000 times using multiple radars and “smart resource scheduling.”
SCMP says the technology allows a centralized networking radar system to enhance the intensity and tracking accuracy of radar signature and save valuable resources for handling other targets by adjusting beam parameters and the power of each radar based on characteristics and real-time positional changes of stealth aircraft, achieving comprehensive tracking of F-22 fighters with just three radars.
The SCMP report says the information can be rapidly transmitted to interceptor fighters or SAM batteries, enabling prompt F-22 fighter intrusions. It notes precise calculations for target coordinates and movement speeds that can reportedly be completed in 0.02 seconds.
SCMP says these radars can be strategically positioned on land, islands, ships and aerial platforms, bolstering China’s anti-access/area denial (A2/AD) in the South China Sea and Western Pacific regions.
Given those challenges, Deaile notes that swarming combined with the saturation of enemy air defenses with attritable drones controlled from B-21s would be the best way to breach enemy air defenses, with the Combined Joint All-Domain Command and Control (CJADC2) essential to create an information-fluent force capable of dominating networks and bombarding targets from multiple locations.
Alongside China’s improving stealth detection technologies, more capable and practical US weapons may bring the possibility of the B-21 being the last new USAF bomber closer to reality.
In December 2022, Asia Times reported on the US Mayhem program, a hypersonic aircraft seen as the successor to the Cold War-era SR-71 Blackbird. Project Mayhem is designed to deliver unitary, area-effect munitions or conduct ISR missions. However, this year, the US pulled funding from the project, citing unclear operational demand for such an aircraft.
However, a more practical option may be integrating a long-range hypersonic weapon into existing aircraft.
This month, The Warzone reported on Lockheed Martin’s recently unveiled Mako hypersonic weapon, designed to be launched from aircraft such as the F-35, F-22, F-18, F-16, and P-8. The Warzone says that the missile has a length of 13 feet and a diameter of 13 inches, weighs 1,300 pounds and can reach a minimum speed of Mach 5 but did not mention the missile’s flight profile.
The Mako may be a more feasible weapon for long-range strikes than the B-21, which is barely out of the prototype stage, and Mayhem, whose future is in doubt.
As the US has 2,456 F-35s as of April 2023, Mako has many potential launch platforms that can be dispersed to multiple bases and allied ships across the Pacific instead of a few large but potentially vulnerable bomber bases such as Guam and Okinawa.