New Report Exposes Serious Weaknesses in Russia’s S-400 Air Defence

A new report by the Royal United Services Institute (RUSI) has uncovered major vulnerabilities in Russia’s S-400 air defence system—one of Moscow’s most celebrated strategic weapons. Despite its reputation as a world-class air defence platform, the S-400 appears heavily dependent on foreign electronics, materials, software, and a fragile production chain that could be targeted to undermine Russia’s operational capabilities.

Foreign Microelectronics at the Core of S-400 Weakness

RUSI’s analysis reveals that key components of the S-400 rely on technology sourced from abroad:

• The system’s sophisticated electronics use materials produced by Rogers Corporation, a U.S. company with loose export controls and a major manufacturing base in China.
• Another essential supplier of components is located in Kazakhstan, remains unsanctioned, and continues providing critical parts.

This dependence makes the S-400 vulnerable to export controls, sanctions pressure, and supply-chain disruption, potentially crippling its production and performance.

Russian Production Facilities Within Ukraine’s Strike Range

The report highlights that the S-400’s guidance and control systems are manufactured at just two sites in Russia—both within the reach of Ukraine’s Flamingo cruise missiles.
This geographic vulnerability exposes the S-400 supply chain to kinetic attack, placing its production capacity at direct operational risk.

Broader Weaknesses Across Russian Air Defence Systems

Beyond the S-400, RUSI notes that nearly all Russian air defence platforms rely on Western-made microelectronics, calibration tools, specialty ceramics, and foreign software used for radar and system design. These dependencies create multiple points of failure that can be exploited through:

• Cyber intrusions
• Export restrictions
• Targeted sanctions
• Disruptive strikes on production nodes

How Ukraine and Its Partners Could Exploit These Vulnerabilities

According to the report, Ukraine and supporting nations could significantly degrade Russia’s air defence capabilities by:

1. Blocking modernisation of Russian microelectronics by targeting critical raw materials and equipment suppliers.
2. Sanctioning providers of beryllium oxide ceramics, essential for radar systems in the S-400 and other platforms.
3. Restricting high-end Western testing and calibration tools used in quality control of air defence equipment.
4. Conducting cyber operations to compromise design software and disrupt production processes.
5. Striking key industrial facilities involved in guidance and radar manufacturing.
6. Imposing sanctions on repair and recovery services, particularly those dependent on Western machine tools.

Such measures could slow or halt Russia’s production of air defence interceptors at a time when Moscow is expending missiles faster than it can replace them.

Implications for Global Customers

RUSI warns that countries which have purchased or are considering purchasing Russian air defence systems—including the S-400—should reevaluate their resilience.
These systems may be vulnerable to:

• Cyberattacks
• Technical compromise
• Supply-chain disruption
• Sanctions pressure

The report suggests that international buyers might face severe maintenance and resupply challenges in a prolonged conflict scenario.

Impact on the Ukraine War

Russia’s air defence network—particularly the S-400—intercepts a majority of Ukrainian strikes targeting energy, industrial, and military infrastructure. If Ukraine and its partners succeed in disrupting interceptor production, RUSI argues, Kyiv could significantly increase damage to Russian targets in 2026, adding pressure on Moscow’s war machinery.