Rocket scientists in China have made a groundbreaking discovery that could have significant implications for the reliability of intercontinental ballistic missiles (ICBMs). A study conducted at the National Key Laboratory of Solid Rocket Propulsion in Xian has revealed a critical issue with the solid fuel used in ICBMs, showing that missile fuel columns may undergo significant changes within just 30 years, potentially jeopardizing their ability to withstand flight stresses.
Led by senior engineer Qin Pengju, the project team identified this issue as a key factor behind the increasing number of ignition and test launch failures witnessed in recent years. Their findings, published in the Chinese peer-reviewed Journal of Propulsion Technology, shed light on the surprising vulnerability of missile fuel despite its typically stable nature for over 160 years under standard storage conditions.
The research focused on the solid propellant commonly utilized in these missiles, which consists primarily of ammonium perchlorate, aluminum powder, and an HTPB binder. Through accelerated aging treatments at elevated temperatures lasting up to a year, the team discovered that while aged propellant appeared stable during routine storage, it exhibited a significant increase in brittleness under high pressure compared to fresh fuel, as reported by the South China Morning Post.
Emphasizing the crucial role of propellant durability in withstanding pressure loads during engine operation to maintain fuel grain structural integrity, Qin’s team highlighted that the propellant’s ductility under pressure could degrade notably within just 27 years. The intricate structure of solid fuel, with its components needing to tightly align with the missile body, demands that the fuel remains ductile under stress to prevent fracturing during launch and ensure optimal performance.
Recent incidents involving the Minuteman III ICBM and the Trident II missile have underscored the pressing need for vigilance in maintaining the long-term effectiveness of these critical deterrent systems. In November 2023, a Minuteman III manufactured by Boeing experienced flight anomalies resulting in its self-destruction, while a Trident II launched from a British Royal Navy submarine suffered a similar failure two months later. These missile types play pivotal roles in the nuclear deterrent forces of the US and its allies, with over 400 Minuteman III missiles still in service, despite being produced in the 1970s, and the Trident II operating for nearly three decades.
The recurring failures observed in Minuteman III inspections and tests, alongside the back-to-back launch failures of the Trident II despite its historically reliable performance, have raised concerns about the operational longevity and reliability of these vital defense systems. The US military has launched comprehensive inspections and assessments to safeguard the reliability of its nuclear arsenal, committing close to $10 billion to extend the service life of its Minuteman III missiles.
In contrast, China, with a smaller nuclear arsenal compared to the US and Russia, has introduced new missile technologies such as hypersonic weapons. Many of these missiles are mobile-launched from platforms like trucks or trains, enhancing their survivability compared to silo-based systems like the Minuteman III.
