Intense air defense warfare reveals bottlenecks in interceptor missile production
Air and missile defense capabilities depend not only on radar and command-and-control systems, but also on the quantity of interceptor missiles that can actually be launched. In particular, in complex attacks involving the simultaneous deployment of ballistic missiles, cruise missiles, and self-detonating unmanned aerial vehicles, the stockpile and production rate of interceptor missiles determine the sustainability of the defense operation.
According to a statement from the U.S. Department of Defense, Iran launched more than 110 intermediate-range ballistic missiles, more than 30 land-attack cruise missiles, and more than 150 unmanned aerial vehicles towards Israel from April 13 to 14, 2024. U.S. Central Command announced that at the time, U.S. Navy destroyers and ships belonging to the U.S. European Command had destroyed more than 80 unmanned aerial vehicles and at least 6 ballistic missiles.
When multiple types of threats are launched in a short period, the air defense network consumes a large number of interceptor missiles in rapid succession. If the conflict is prolonged, the problem shifts from the performance of individual interceptor missiles to how quickly and reliably the core propellants can be replenished.
Why solid rocket motors are crucial for missile defense
Solid rocket motors (SRMs) are propulsion devices that use a solid propellant consisting of fuel and oxidizer, which is packed inside a casing. They can generate high thrust simultaneously upon ignition, making them widely used in ground-to-air, air-to-air, and ballistic missile interception systems that require rapid acceleration and immediate response.
The U.S. Government Accountability Office (GAO) explained that solid rocket motors provide propulsion for a variety of missiles, ranging from short-range tactical missiles to long-range strategic weapons. While they have a simpler structure compared to liquid propulsion systems and are suitable for long-term storage, they generally have the characteristic that thrust is difficult to stop or restart after ignition.
Solid Rocket Motors (SRMs) for missile defense systems require more than just high speed. They must generate precise thrust at a predetermined time and operate without cracks, adhesive failure, or propellant degradation, even after long-term storage. Some interceptor systems use multi-stage or multi-pulse motors to adjust thrust during different flight phases, which makes the manufacturing and quality assurance processes complex.
Supply chain vulnerabilities are hidden beneath the finished products
The SRM supply chain consists of several sub-supply chains, including those for propellants and additives, motor casings, insulation materials, igniters, nozzles, and electronic components. If even a single item in any of these sub-supply chains relies on a single supplier or if production is halted, the entire schedule for the final missile assembly can be affected.
A 2017 investigation by the GAO (United States Government Accountability Office) revealed that the number of major SRM (Solid Rocket Motor) manufacturers in the United States decreased from 6 in 1995 to 2. During the same period, one manufacturer estimated that the number of raw material, component, and sub-system suppliers decreased from approximately 5,000 to 1,000. This increased the risk that disruptions in the supply of specific materials or components could lead to production delays.
Solid rocket motors, unlike general manufacturing, cannot immediately increase production volume simply by expanding facilities. They require propellant mixing and casting, a long curing process, non-destructive testing, and static burn tests. Facilities that handle explosive materials are subject to strict safety distances and licensing requirements.
The Center for Strategic and International Studies (CSIS), in a report released in June 2026, identified recurring demand fluctuations, complex multi-stage supply chains, and a misalignment of investment incentives between the government and companies as major obstacles to expanding production in the Surface-to-Air Missile (SAM) defense industry. This means that short-term increases in orders alone make it difficult for companies to make long-term investments in new factories and skilled personnel.
United States strategy for expanding solid rocket motor production
The United States is using the Defense Production Act and defense industrial base investment funds to simultaneously expand the production facilities for SRM (Solid Rocket Motors) and the supply chain for key chemical materials. According to the U.S. Department of Defense’s budget data for the 2026 fiscal year, approximately $260,000,000 will be allocated from the fiscal years 2024 to 2026 to enhance solid rocket motor manufacturing capabilities, and approximately $117,000,000 will be used to address deficiencies in the missile and ammunition sectors, including the supply of key chemical materials.
Efforts are also underway to diversify suppliers. The U.S. Department of Defense announced that it will provide $14,300,000 to Anduril under the Defense Production Act in January 2025. This project, linked to the company’s $75,000,000 in private investment, will expand the design, production, and testing capabilities of the Mississippi facility, as well as the propellant casting and curing processes.
These investments are significant not only because they increase the production capacity of existing large manufacturers, but also because they secure new sources of supply. However, for new companies to actually participate in mass production, they must pass the stages of verifying the performance and safety of the propulsion system, obtaining certification for each weapon system, and stabilizing quality through repeated production.
Four challenges for strengthening the SRM supply chain
Long-term contracts must provide predictable demand
If the government repeatedly issues orders for only a single year, companies may hesitate to make large-scale investments in equipment due to the risk of economic fluctuations and project cancellations. To encourage investment in production facilities and skilled personnel, it is necessary to provide a long-term demand through multi-year contracts and minimum purchase quantities.
Sub-suppliers should be inspected before completing the motor
The expansion plan for production must include suppliers of all necessary components, including propellant raw materials, special chemicals, nozzles and casings, insulation materials, and testing equipment. For each critical component, a second supplier should be certified, and, if necessary, the government should provide stockpiles and support domestic production.
Testing and certification capabilities must be increased in conjunction with production facilities
If only the casting and assembly capabilities are expanded, and non-destructive testing or combustion testing facilities are not increased, the bottleneck in the production process will shift to the final stage. It is also necessary to have digital quality control that can quickly approve design changes and new materials, as well as standardized certification procedures.
Interception methods should be categorized by threat type
Expanding the production of Surface-to-Air Missiles (SAMs) alone cannot solve all air defense problems. A layered defense is necessary, prioritizing electronic warfare, autocannons, and small interceptor missiles for low-cost unmanned aerial vehicles (UAVs), while allocating high-performance interceptor systems for ballistic missiles. This approach can reduce the unnecessary consumption of expensive interceptor missiles and preserve strategic reserves.
Conclusion: The sustainability of missile defense is determined in the factory
The weaknesses of modern air and missile defense systems are not limited to detection range or interception accuracy. Even the most advanced defense systems will struggle to sustain operations for extended periods if interceptor missiles cannot be replenished in a timely manner during intense combat.
To strengthen the solid rocket motor supply chain, the following measures should be implemented as a unified policy: expanding production facilities, encouraging new companies to enter the market, securing multiple sources for key materials, expanding testing facilities, and implementing multi-year procurement programs. The solid rocket motor industry should be regarded as a core power that supports the nation’s missile defense posture, rather than simply addressing component supply issues for interceptor missiles.
Frequently Asked Questions (FAQ)
What are the differences between solid rocket motors and liquid rocket engines?
Answer: Solid rocket motors store the fuel and oxidizer in a solid state inside the motor, providing high thrust immediately upon ignition. While their structure and operation are relatively simple, they generally cannot be stopped or restarted after ignition.
What types of missiles use solid rocket motors?
Answer: It is used in various weapon systems that require rapid response and long-term storage, including air-to-air and surface-to-air intercept missiles, ballistic missile defense systems, anti-tank missiles, and tactical surface-to-surface missiles.
What are the reasons why it is difficult to increase the production volume of SRM in a short period?
Answer: This is because the mixing, casting, and curing of explosive propellants require time, and non-destructive testing and combustion tests must be performed. New equipment and suppliers must also obtain safety and performance certifications.
What is the biggest risk in the solid rocket motor supply chain?
Answer: The reliance on a single supplier for specific raw materials and components is a key risk. An accident or production disruption at one supplier can simultaneously affect multiple missile programs.
Does expanding SRM production alone solve the missile defense problem?
Answer: No. A multi-layered defense system must be established, combining sufficient interceptor missile reserves with radar, command and control, electronic warfare, and low-cost anti-drone measures, in order to respond to prolonged and complex attacks.
