America’s First New ICBM in 60 Years Faces Further Major Delays: Urgent Sentinel Flight Testing Now Four Years Behind Schedule

Continued restructuring of the Sentinel intercontinental range ballistic missile (ICBM) program has increased <a href="https://militarywatchmagazine.com/article/usaf-icbm-struggling-urgent-collapse" >uncertainty</a> regarding the beginning of the flight testing phase, with an Air Force official having confirmed that while the missile’s first test flight, which was previously scheduled for 2026, no longer has a confirmed date. The first test flight was beforehand scheduled for 2023-2024, but has been delayed by over two years. “The team is actively assessing the overall schedule, including potential impacts on the timeline for the first full-system flight,” the official stated, citing among other factors the 81 percent rise in costs in 2024. The Government Accountability Office reported that the first flight test is now scheduled for March 2028, placing it four years behind schedule. The Sentinel is the first new class of intercontinental range ballistic missile developed in the Western world since the Minuteman, with the latest variant of the older Cold War era missile, the Minuteman III, having seen its first test flight in August 1968, 60 years before the expected Sentinel test date.<img src="https://militarywatchmagazine.com/m/articles/2025/06/13/article_684cac639cb026_64216049.jpg" title="Minuteman III ICBM Launch">Bringing the Sentinel into service is considered particularly urgent due to the age of the Minuteman III arsenal, which has been pushed to its absolute limit for life extension. The missiles have been in service since 1970, and are several decades past their originally intended service lives. As previously observed by Commander of the United States Strategic Command Charles A. Richard: “You cannot life-extend Minuteman III… It is getting past the point of [where] it’s not cost-effective to life-extend Minuteman III. You’re quickly getting to the point [where] you can’t do it at all.” &nbsp;Richard warned that the&nbsp;missiles in the existing arsenal were so obsolete that their original designers were dead, and engineers no longer even had some of the necessary technical documentation. “That thing is so old that in some cases the [technical] drawings don’t exist anymore, or where we do have drawings, they’re like six generations behind the industry standard. And there’s not only [no one] working that can understand them – they’re not alive anymore,” he stated. The alternative to developing the Sentinel is to <a href="https://militarywatchmagazine.com/article/abandon-nuclear-triad-us-icbm" target="_blank">abandon</a> the third arm of the American nuclear triad, and increase investment in ballistic missile submarines and strategic bombers.&nbsp;<img src="https://militarywatchmagazine.com/m/articles/2025/06/13/article_684cac7d6c17e9_99713829.jpeg" title="Chinese DF-41 ICBMs on Parade">Struggles developing the Sentinel ICBM have occurred as China, Russia and North Korea continue to <a href="https://militarywatchmagazine.com/article/russia-reequips-icbm-division-fastest-reentry-vehicles-avangard" target="_blank">rapidly modernise</a> their own ICBM arsenals, with the former two having integrated hypersonic glide vehicles capable of intercontinental range strikes, while the Korean People’s Army <a href="https://militarywatchmagazine.com/article/nkorea-hwasong16b-hypersonic-changer" target="_blank">did so </a>on intermediate range missiles in 2024, and is expected to also do so for ICBMs in the near future. The Minuteman III, by contrast, is the oldest class of ICBM in service worldwide by a margin of several decades. The lack of experience developing an ICBM has reportedly been a major contributor to the difficulties faced in developing the missile. In June 2024 U.S. Air Force Colonel Charles Clegg was <a href="https://militarywatchmagazine.com/article/head-sentinel-icbm-development-woes" >removed from his position</a> as director of the Sentinel intercontinental range ballistic missile program on June 24, with the service citing a “loss of confidence” in his ability, and stating that he “did not follow organisational procedures.” The House Appropriations Committee stated at the time that it “was stunned to learn” of the massive increases in the program’s costs. The cost per missile was at the time projected at $162 million in 2020 dollars, compared to an initial projection of just $118 million. These cost overruns have occurred as the Air Force <a href="https://militarywatchmagazine.com/article/us-cancels-vital-e7-flying-radar-program-track-chinese-stealth" target="_blank">contends with</a> an <a href="https://militarywatchmagazine.com/article/us-air-force-f35-orders-cut-50pct-sixth-generation" target="_blank">increasingly strained budget</a>, with two new bomber programs, continued procurement and sustainment of the F-35A, development of the F-47 fighter, and development of an AEW&amp;C system and a more survivable class of tanker, being among the major investments seen as highly urgent.&nbsp;