The United States Air Force's next-generation intercontinental ballistic missile is edging toward its first test flight, but the infrastructure needed to deploy it at scale remains years from completion, costs are still climbing, and the arms control framework that governed nuclear arsenals for half a century has just expired. For Australia and its partners in the Five Eyes alliance, the implications are considerable.
The LGM-35A Sentinel, built by Northrop Grumman, is scheduled for its inaugural test launch from a surface pad at Vandenberg Space Force Base in California in 2027. Senior US military officials confirmed the timeline this week at the Air and Space Forces Association's annual Warfare Symposium near Denver, according to Ars Technica. The missile is intended to replace the Minuteman III fleet, which has been on alert since 1970 and is, by any measure, long overdue for retirement.
The programme's fiscal record is, to put it plainly, alarming. Two years ago, the Air Force disclosed that the Sentinel's estimated cost had ballooned from $77.7 billion to nearly $141 billion, triggering what is known as a Nunn-McCurdy breach, a statutory review process for defence programmes that overshoot their original budgets by significant margins. The Pentagon concluded the programme was too critical to national security to cancel, but the $141 billion figure is already considered out of date. A full restructured cost estimate is not expected to be made public until later this year.
The silo problem is, if anything, more embarrassing than the budget figures. The original plan called for adapting existing Minuteman III silos to house the Sentinel. Engineers determined that approach would take too long and cost too much, so the Air Force is now digging hundreds of entirely new holes across Colorado, Montana, Nebraska, North Dakota, and Wyoming. The project will include 24 new forward launch centres, three centralised wing command centres, and more than 8,000 kilometres of fibre connections. The US Army Corps of Engineers notes that the military stopped constructing new missile silos in the late 1960s. The institutional knowledge, it turns out, does not simply wait on a shelf.
"It's been a very, very long time since we've done this," said General Dale White, the Pentagon's director of critical major weapons systems. "At the very core, there were assumptions that were made in the strategy that obviously didn't come to fruition."
One consequence of building new silos rather than repurposing old ones is that the Minuteman III will remain operational far longer than planned. According to the US Government Accountability Office, the ageing missiles could remain on alert until as late as 2050, compared with an earlier retirement target of around 2036. That is a 14-year extension for a weapons system designed in the 1960s. Northrop Grumman broke ground on the first prototype Sentinel silo in Promontory, Utah, earlier this month. The Air Force has ordered 659 Sentinel missiles in total, with more than 400 designated for operational alert status.
The end of New START and what it means
Layered over the programme's construction difficulties is a far larger strategic shift. The New START treaty between the United States and Russia expired on 5 February 2026, leaving both nations without any binding nuclear arms control agreement for the first time since 1972. The treaty had capped deployed warheads at 1,550 per side and required regular mutual inspections. Both mechanisms are now gone.
One immediate consequence is that land-based ICBMs can now legally carry Multiple Independently targetable Reentry Vehicles, known as MIRVs. These allow a single missile to deliver several warheads to different targets simultaneously, making them considerably harder for missile defence systems to intercept. The Air Force removed MIRVs from its Minuteman III fleet in 2014 to comply with New START. Admiral Rich Correll, head of US Strategic Command, confirmed this week that the option to "reMIRV" the Sentinel is now on the table, though he described it as a presidential-level decision.
The Trump administration has signalled it wants a new arms control arrangement that includes China, which was never party to New START. US officials met with Russian and Chinese delegations on arms control discussions this week, though there is no certainty any formal treaty will result. Some analysts expect any agreement to take the form of informal political commitments rather than ratified legal instruments, which would offer far weaker guarantees.
Ankit Panda of the Carnegie Endowment for International Peace put the concern plainly: "The expiration of this treaty is going to lead us into a world for the first time since 1972 where there are no limits on the sizes of those arsenals. This opens up the question of whether we're going to be heading into a world that's just going to be a lot more unpredictable and dangerous when you have countries like the United States and Russia that have a lot less transparency into each other's nuclear arsenals."
The case for and against land-based missiles
The Sentinel programme has revived a long-running debate among strategists about whether land-based ICBMs serve their intended purpose. Critics point out that the locations of America's missile fields are well known, making them obvious targets. Unlike submarines or bombers, silo-based missiles cannot be moved or hidden. Proponents counter that this vulnerability is, paradoxically, the point: an adversary wanting to neutralise America's land-based deterrent would need to target hundreds of dispersed silos, absorbing enormous resources and inviting devastating retaliation. This logic has given rise to the somewhat grim term "nuclear sponge" to describe the ICBM fields.
Both arguments have genuine merit, and neither side of the debate is being frivolous. The reality is that nuclear deterrence strategy has always rested on a series of uncomfortable trade-offs, and the Sentinel programme crystallises several of them at once: fiscal discipline versus strategic capability, arms control versus operational flexibility, modernisation versus the risk of triggering a new arms race.
For Australia, the stakes in this debate are not abstract. The AUKUS partnership ties Australian security directly to US nuclear strategy and capability. A less predictable nuclear environment between Washington, Moscow, and Beijing creates precisely the kind of strategic uncertainty that makes regional security harder to manage. Whether the Sentinel eventually flies on schedule, on budget, and under some new arms control framework or none at all, the outcome will shape the security environment in which Australia operates for decades to come. Informed scrutiny of these decisions, rather than deference or alarm, is the appropriate Australian response.