"LRSO reported unfavorable cost and schedule changes over the past year," GAO reported.
GAO: Flight-testing setbacks and a four-month slip
The Government Accountability Office (GAO) says flight testing for the AGM-181A Long-Range Standoff (LRSO) missile has been hindered largely by "poor readiness rates of legacy aircraft supporting LRSO testing," producing a four-month delay to the program's initial capability. The Air Force now aims to reach initial operational capability with the AGM-181 in November 2030.
Developmental flight testing began in October 2024; GAO reports nine LRSO test flights since that start date, with six of those flights and seven ground test events occurring in the last year. A December 2022 Pentagon disclosure recorded nine earlier test flights; whether additional flights took place between that disclosure and October 2024 is unclear in the record GAO reviewed.
Program officials realigned the test schedule, GAO notes, leaving less time to complete 27 remaining test flights before operational testing begins in September 2027. Officials also told GAO that some re-testing can still be accommodated.
B-52 availability: fleet size, mission-capable rates, and operational use
The B-52 is the only aircraft publicly known to be participating in LRSO flight testing. The Air Force currently has 75 B-52H bombers in service. GAO records mission-capable rates for the fleet "hovering between 50 and 55 percent" in recent years, and notes that the entire fleet is never available at once because of routine maintenance and other factors.
Only one B-52 is explicitly set aside to support test and evaluation efforts; additional aircraft from operational units are used on an ad hoc basis to support research, development, and test activity. The fleet also faces heavy operational demands, including conventional combat operations and nuclear forces duties. GAO highlights heavy B-52 utilization earlier this year for conventional strikes on Iran as an added strain.
Operational pressure and fleet size have complicated modernization and sustainment. Air Force Gen. Dale White, the service’s Direct Reporting Portfolio Manager for Critical Major Weapon Systems, told the Air & Space Forces Association’s Warfare Symposium that "it’s such a small fleet that has such a tremendous requirement in terms of readiness" and that depot choreography to maintain readiness while meeting operational requirements "is going to be tough." The report also notes that last month one B-52 was lost in a fatal crash at Edwards Air Force Base—an accident that occurred after GAO’s cutoff date and therefore is not reflected in its assessment.
Software, cybersecurity, and technical maturity
GAO’s assessment details software and technical risks that extend beyond aircraft availability. Program officials told GAO that 12 of 14 software releases are delivered, with the final release planned for March 2026. They identified nuclear certification of LRSO software as a continuing risk expected to be fully addressed by November 2026; GAO repeated its earlier warning that the program risks delays if additional software development is required to meet that certification.
Cybersecurity testing of LRSO continues with some delays reported during the past year; program officials said these delays have not yet caused cost or schedule changes, and the final cybersecurity assessment remains planned for September 2027.
On technology maturity, GAO reports that four of six critical missile technologies are mature, while two are "approaching maturity" and are expected to be fully mature in fiscal year 2026—about five years after development started. The Department of Energy (DOE) identified critical technologies for the warhead, of which 80 percent are considered mature, a substantial increase from last year; DOE may not mature all remaining warhead technologies until the fourth quarter of fiscal year 2026. GAO reiterated that both missile and warhead began development with immature technologies, a concurrency that departs from the best practice of starting with mature technologies and increases risk of cost growth and schedule slips.
Cost growth, production timing, and a $1.9 billion disagreement
GAO documents cost movement and a notable discrepancy in production estimates. Program costs increased by $347 million after Air Force leadership directed a one-year extension to LRSO production due to near-term budget constraints. Separately, GAO reports that Office of the Secretary of Defense (OSD) and Air Force officials continue to work to resolve a $1.9 billion difference between their production cost estimates for future LRSO production.
A fully updated estimate is not expected until later in 2026; program officials now agree that OSD’s higher cost estimate should provide the appropriate basis for the program’s fiscal year 2027 budget request and future-year procurement funding needs. Despite these issues, GAO says the Air Force remains confident it can start low-rate initial production (LRIP) next year, a milestone the service sees as key to staying on schedule for fielding missiles by 2030.
What this means for the Air Force, the DOE, and the OSD
- For the Air Force: limited B-52 availability, ongoing modernization work (including a radar modernization and re-engining program that will redesignate aircraft as B-52J) and competing operational demands mean test schedules will require careful sequencing to meet LRIP next year and initial operational capability in November 2030.
- For the Department of Energy: DOE’s warhead-technology schedule—80 percent mature with remaining technologies potentially maturing in Q4 FY2026—will be a pacing item for certification and production plans tied to the missile.
- For the Office of the Secretary of Defense: the $1.9 billion production-cost difference with the Air Force and the decision to use OSD’s higher estimate as the basis for FY2027 budgeting place budget reconciliation and oversight squarely in OSD’s and congressional purview through the rest of 2026.
The AGM-181A has been under development since 2020, with Raytheon selected as prime contractor. GAO’s report frames the program at a narrow junction: recent flight-test successes sustain confidence in near-term milestones, but constrained B-52 availability, outstanding software certification and cybersecurity work, remaining technology maturation for missile and warhead components, and a meaningful production-cost dispute together leave the program dependent on a handful of precise dates—final software delivery in March 2026, nuclear software certification by November 2026, an updated cost estimate later in 2026, a cybersecurity assessment in September 2027, LRIP next year, and initial operational capability in November 2030.
