Forty years later: what will replace the AGM-86B ALCM?
Since 2017, the Pentagon and its contractors have been developing the advanced AGM-181 LRSO air-launched cruise missile. The program has already passed some key milestones, but is still far from complete. Therefore, the US Defense Department is proposing to accelerate the work and bring the new missile into service closer.
Request for acceleration
The US is currently preparing the federal budget for fiscal year 2027, which begins on October 1, 2026. Specifically, the Pentagon budget and other defense spending are being worked on. On the last day of April, the agency submitted its current budget request to Congress.
The draft military budget includes funding for continued development of the LRSO (Long-Range Stand Off) air-launched cruise missile, or AGM-181. This system has now entered the flight testing phase, but is not yet ready for operational use.
The Pentagon notes the significant significance of the LRSO project in the context of developing the armed forces' strike capabilities. The Defense Ministry notes that in recent years, Russia, China, and other countries have built sophisticated air defense systems based on modern radars, anti-aircraft systems such as the S-400 and Hongqi-9, electronic warfare systems, and other technologies.
According to the Pentagon, such systems Defense Capable of detecting and engaging modern aircraft and air attack assets. The effectiveness of existing weapons is declining, and new technology is needed to replace them. This will include the LRSO-type ALCM, currently under development.
To accelerate work on the project, $1,5 billion is proposed for allocation in fiscal year 2027. For comparison, the program received $693,8 million in fiscal year 2025, $897,1 million in fiscal year 2026, and appropriations will almost double in fiscal year 2027. This is due to the so-called Milestone C milestone—the formal decision to transition to low-volume production—being scheduled for fiscal year 2027.
The future spending dynamics are expected to be even steeper. The current plan proposes $1,76 billion for FY2028 and $2,29 billion for FY2029, with the share of procurement spending increasing and development spending decreasing. According to Pentagon calculations, this schedule will allow for the launch of low-volume production as early as 2027–2028, and for operational readiness in combat units to be achieved in 2029–2030. Then, in the 2030s, a full-scale rearmament of the strategic air force is planned. aviation.
According to public estimates, the total procurement volume will be approximately one thousand missiles. The total cost of the program is approximately $20 billion, excluding operational costs; assuming a 30-year service life, the total cost of ownership is estimated at approximately $33 billion.
LRSO components under the wing of a B-52H, November 2025. Photo: Telegram / BMPD
Congress has already reviewed the Pentagon's proposals but has not yet given a definitive assessment. Discussions and adjustments to the military budget could take several more months. The final budget for the LRSO project will become clear by the fall.
A long way from idea to testing
It's worth remembering that the proposal to develop a new ALCM for strategic aviation was first voiced in the first half of the 2010s. The plan was to launch its development by the middle of the decade, and to have a ready-made version in the 2020s. weaponHowever, for a number of reasons, the launch of the LRSO program was delayed for several years.
It wasn't until August 2017 that the Pentagon awarded contracts to Raytheon and Lockheed Martin for the competitive development of a new missile. This phase continued until the spring of 2020, when Raytheon's YAGM-181A design was announced as the winner of the program.
The necessary consultations and approvals took about a year and a half. It wasn't until July 2021 that Raytheon received the contract to complete the design and conduct flight tests of the missile. Based on this document, the development cost was expected to exceed $2 billion.
In 2022, the first tests of the new ALCM took place in secrecy. According to information published later, nine flight tests were conducted from February to October of that year from two dedicated B-52H bombers. Some of these were limited to testing safe separation from the launch vehicle and control surface deployment; in four cases, the missile's cruise engine was ignited. The culmination was the CTM-1 test in October 2022, during which, according to the Pentagon, the entire system was tested: separation from the B-52, engine ignition, sustained controlled flight, and mission profile development.
In FY2023, the program conducted six more flight tests, primarily focused on safe separation testing and reliability data collection. Then, in November 2025, bystanders photographed a B-52H carrying two components that externally matched the LRSO design concept published by the Air Force in June of that year. Similar photos appeared in March 2026, indicating continued testing. However, the Pentagon and Raytheon are reluctant to share details.
In fiscal year 2027, the Pentagon plans to accelerate the LRSO program. This will increase the number of test launches and/or shorten the intervals between them. At the same time, preparations for serial production of the new weapon and its adoption will proceed.
B-52H with experimental missiles, March 2026. Photo: Telegram / BMPD
What is known about the AGM-181
The AGM-181 LRSO is an air-launched cruise missile designed for strategic aviation. It is planned to be used in the future to strike remote enemy targets of particular importance. In the Air Force arsenal, the new LRSO will replace the AGM-86B ALCM, which has been in service since December 1982.
The LRSO has a technical appearance typical of such weapons. It features a stretched, streamlined fuselage, which reduces radar signature. It has a low-wing wing that folds out in flight, and a tail assembly with a stabilizer and lower vertical stabilizer. Available images reveal characteristic radar cross-section reduction techniques: faceted contours, a wedge-shaped nose, and coordinated surface angles.
The missile's dimensions and launch weight remain unknown. The only indirect information is that the LRSO is longer than its predecessor, which necessitated the development of a special Bomber Weapon Interface Equipment (BWIE) for the B-52H. The Air Force announced a tender for the B-52H in January 2024.
The missile is powered by a compact Williams F107 turbojet engine, which provides high subsonic flight speeds. Its range is expected to exceed 2,5 km. The onboard control system includes various types of navigation instruments: satellite, inertial, and terrain reference map (TERCOM). The autopilot will ensure flight to a target with predetermined coordinates.
The warhead is a W80 Mod 4 (W80-4) thermonuclear warhead, developed under a service life extension program managed by the NNSA. The yield of the warhead is not disclosed; previous W80 modifications had a variable yield from 5 to 150 kt. The W80-4 program is in Phase 6.4 (production engineering), and the first production warhead (First Production Unit) is scheduled for September 2027—that is, in sync with the missile's entry into low-volume production. The possibility of equipping the LRSO with a conventional (non-nuclear) warhead was previously considered, but this was abandoned. Non-nuclear strikes are planned using other types of ALCMs.
The B-52H strategic bomber is currently in the testing phase as the prototype carrier for the AGM-181 missile. This strike system will subsequently enter combat service. The new missile will also be deployed on the future B-21 Raider bombers; the second flight prototype of the B-21 was deployed to Edwards Air Force Base in September 2025, allowing for mission systems and weapons integration testing. No reports have yet been made regarding LRSO testing directly on the B-21.
A W80 Mod 4 experimental warhead. Photo by the US Department of Energy.
Place in the nuclear triad
The LRSO missile is of particular importance to the Pentagon and the United States as a whole. It is currently one of the key strategic nuclear forces programs. Its completion should improve the airborne component of the strategic nuclear forces' quantitative and qualitative capabilities.
The AGM-181 is designed to replace the AGM-86 ALCM and offers several advantages over it. Chief among these is the time factor. The existing AGM-86B was produced in the first half of the 1980s and is gradually reaching the end of its service life. In March 2025, the US Air Force was forced to sign a separate contract with Boeing to extend the service life of the AGM-86B fleet until 2033—effectively a "cradle" designed to bridge the gap between the retirement of the old missile and the arrival of the new one. Production LRSOs will not face the issue of service life exhaustion for a long time, which in itself makes the program irrelevant: the Air Force simply cannot afford to be without an air-launched ALCM in its strategic nuclear forces.
The second set of advantages is the technical and technological level of the new missile. Both ALCMs have similar speeds, but the LRSO has an increased range—over 2500 km versus approximately 2400 km for the AGM-86B (according to other estimates, up to 1500 miles). This understandably expands the operational capabilities of strategic missile carriers, extending their launch ranges beyond the engagement zones of modern air defenses.
The air defense itself is the third key argument in favor of the new missile. The Pentagon directly cites the threat posed by current foreign air defense systems and the difficulty of overcoming such defenses with older missiles. The AGM-181 design incorporates modern stealth measures, which, according to the developers, should restore the air-launched ALCM's ability to reliably reach its target. In March 2025, General Anthony Cotton, Commander of the United States Strategic Command (USSTRATCOM), testifying before Congress, called the LRSO "an essential part of next-generation deterrence," noting that the missile must offer flexible and scalable options capable of "penetrating and surviving" modern air defenses.
Finally, the new project takes into account strategic aviation development plans. The LRSO will be one of the first munitions in the US Air Force to be developed from the ground up with the B-21 bomber in mind. This means compatibility with its internal compartments and interfaces, as well as consistency in stealth measures at the carrier-weapon level.
The LRSO program is integrated into a broader strategic nuclear force modernization plan. The FY2027 budget requests approximately $71 billion for nuclear force modernization overall: in addition to LRSO, this includes the new silo-based LGM-35A Sentinel ICBM, the Columbia-class SSBN, and the B-21 bomber itself. All three programs are being developed in parallel, and their readiness deadlines are interconnected: a delay in one program impacts the other two.
Thus, the new AGM-181 LRSO ALCM should help US strategic aviation update its arsenals and maintain the required strike power. However, achieving these goals requires investment of money, effort, and time. To reduce the timeframe, the Pentagon is proposing to increase funding for the project.
Whether this request will be successful in passing all the required procedures remains to be seen. The military modernization of the US strategic nuclear forces is proceeding across several costly areas, with each program vying for its share of the budget. However, the Pentagon has ample time to convince lawmakers of the need for increased attention to LRSO: the alternative is to leave the air component of the triad, with its aging missiles from the 1980s, indefinitely, making do with extended contracts like the March deal with Boeing.
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