US approves $1.7B Aegis combat system upgrade for five Spanish F-100 frigates.

The United States has authorized a $1.7 billion Foreign Military Sale enabling Spain to modernize its five F-100 Álvaro de Bazán-class frigates, focusing on updated Aegis combat system hardware, software, sensors, and launch systems.

On January 29, 2026, the United States approved a $1.7 billion Foreign Military Sale enabling Spain to modernize its five F-100 Álvaro de Bazán-class frigates through updated Aegis combat system hardware, software, sensors, and launch systems. The upgrade is intended to maintain fleet air defense capability, ensure NATO interoperability, and extend the ships’ service life to approximately 2045.
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The five F-100 frigates, also known as the Álvaro de Bazán-class, were built by Navantia and delivered to the Spanish Navy between 2002 and 2012, forming the first class of Aegis-equipped European air defense frigates. (Picture source: Spanish Navy)

More precisely, launcher and sensor integration are addressed through five shipsets of the Mk 41 Baseline VIII Vertical Launching System and five shipsets of next-generation surface search radar. The package also includes ultra-high frequency satellite communications radio terminal systems to support long-range connectivity. Navigation and timing resilience are reinforced through the inclusion of GPS Miniature Precision Lightweight Receiver Engines with M-Code. Additional elements include AN/SRQ-4 Ku-band hardware and materials to support upgrading the NIXIE SLQ-25A torpedo countermeasure to the SLQ-25E standard. The scope also covers Mk 331 torpedo setting panels and Mk 32 surface vessel torpedo tube upgrades to maintain torpedo employment and control functions. U.S. Government support for the Mk 45 Mod 2 and Mod 2B gun weapon system is included to ensure continued integration with the combat system.

The Aegis combat system was developed in the United States in the late 1960s as a response to the increasing threat posed by high-speed anti-ship missiles and massed air attacks against surface fleets. The program emerged after the cancellation of earlier naval air-defense concepts and was shaped by the need to combine radar detection, tracking, command-and-control, and weapon guidance within a single integrated architecture. Development work focused on fixed phased-array radar technology, advanced computing, and automated threat evaluation, allowing continuous surveillance without mechanical antenna rotation. The first operational installations appeared in the early 1980s, initially on U.S. Navy cruisers, before expanding to destroyers and later export customers. Over time, the system evolved through successive software and hardware baselines, allowing Aegis systems to expand their tasks beyond area air defense to include surface warfare coordination and ballistic missile defense.

The Aegis is an integrated naval combat system that links sensors, weapons, and command functions through centralized computers and automated decision logic. Its core components include the AN/SPY-1 multifunction phased-array radar, the Mk 99 fire control system, command-and-decision computers, weapon control elements, and interfaces with the Mk 41 Vertical Launching System. The radar performs simultaneous search, track, and missile guidance tasks, while digital signal processors manage radar returns and data fusion. The command-and-decision element evaluates threats, assigns priorities, and selects appropriate weapons under time constraints. Missile engagements rely on continuous data exchange between radar, fire control illuminators such as the AN/SPG-62, and interceptors from the Standard Missile family. This architecture enables multiple, concurrent engagements against air and missile targets within a single combat system framework.

The Aegis combat system is installed on a broad range of surface combatants operated by the U.S. Navy and several allied navies, including cruisers, destroyers, and large frigates designed to accommodate its radar and power requirements. U.S. vessels include Ticonderoga-class cruisers and Arleigh Burke-class destroyers, while allied users include Japan, Spain, Norway, South Korea, Australia, and Canada. The system has also been adapted into a land-based configuration using similar radar, command, and launcher components for missile defense roles. Although ship sizes and missions vary, all Aegis-equipped vessels share common combat-system principles, software lineage, and missile interfaces. Data links such as Link-11 and Link-16 enable interoperability among Aegis ships and other allied units. As of the mid-2020s, more than one hundred Aegis-equipped ships are active worldwide, with additional units planned or under construction.

The five Spanish F-100 frigates, also known as Álvaro de Bazán-class, originated in the 1990s following Spain’s decision to replace older escorts and to abandon earlier multinational frigate initiatives. Five ships were built by Navantia at Ferrol and entered service between 2002 and 2012, making them the first European surface combatants designed from the outset around the Aegis system. As the class reached roughly half of its intended service life, Spain initiated a mid-life upgrade program to address obsolescence and maintain operational availability. This modernization includes combat-system renewal, digital processing upgrades, radar and launcher baseline updates, and associated support elements. National planning links the effort to an industrial program estimated at €3.2 billion over about 120 months. The objective is to extend the operational life of the class to approximately 2045.

The Álvaro de Bazán-class was engineered to integrate the Aegis system within a frigate-sized hull while meeting power, cooling, and stability requirements. The ships feature a steel hull and superstructure configured to support the fixed AN/SPY-1 radar arrays and associated equipment. Machinery is installed on resilient mountings to reduce acoustic signatures, supporting anti-submarine operations. Hull and superstructure shaping incorporates measures to limit radar cross-section compared with earlier Spanish escorts. The internal layout provides space, weight, and power margins intended to accommodate future upgrades. These design choices enabled the class to accept successive combat-system modernizations without fundamental structural changes.

The ships were designed as multi-mission escorts with primary roles in fleet air defense, surface warfare, and anti-submarine operations, with a strong emphasis on interoperability with allied naval forces. Therefore, the weapon fit of the F-100 frigates is centered on a 48-cell Mk 41 Vertical Launching System, which supports surface-to-air missiles such as the SM-2 and the RIM-162 Evolved Sea Sparrow Missile for area and point air defense. A 127 mm Mk 45 naval gun provides surface engagement and naval gunfire capability, integrated with ship fire-control systems. Anti-ship warfare is handled through dedicated missile launchers, while two Mk 32 torpedo tubes support lightweight torpedoes for anti-submarine warfare. Each ship operates an embarked SH-60 Seahawk helicopter, extending sensor reach and undersea warfare capability. Defensive systems include electronic warfare equipment, decoy launchers, and a towed torpedo countermeasure.

The first four F-100 units have a standard displacement of 5,800 tonnes, while the fifth ship displaces roughly 6,400 tonnes, with an overall length of 146.7 meters and a beam of 18.6 meters. Propulsion is provided by a combined diesel or gas arrangement using two General Electric LM2500 gas turbines and diesel engines driving two propellers. Maximum speed is approximately 28 knots, with a range of around 4,500 to 5,000 nautical miles at cruising speed. Crew complements are typically about 200 to 216 personnel, depending on configuration. The ships are designed for sustained blue-water operations and integration into multinational task groups. Within the Spanish Navy’s future force structure, the F-100 class is expected to operate alongside the newer F-110 frigates, sharing escort and fleet-defense tasks while relying on different generations of combat systems. The mid-life upgrade is designed to bridge this transition period without creating capability gaps.

Spain's F-100 frigate mid-life upgrade (MLU) outlines a long-duration industrial effort estimated at €3.2 billion over approximately 120 months from execution, with work centered at the Ría de Ferrol shipyard. The objective is to extend the operational life of all five ships to around 2045 while eliminating identified obsolescence and increasing commonality among onboard systems. Planning references an average annual economic impact of about €215 million and approximately 3,500 jobs, including direct, indirect, and induced employment. The program is linked to Spain’s Industrial and Technological Plan for Security and Defense approved in April. Environmental compliance and efficiency improvements are included among the objectives. The effort combines military sustainment with broader industrial considerations.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.