The U.S. Navy has marked the delivery of its 1,000th Evolved SeaSparrow Missile (ESSM) Block 2, a major production milestone for a multinational naval air-defense program. The achievement comes as Red Sea combat operations have highlighted the need to maintain sufficient missile inventories to protect warships against repeated aerial attacks.Announced November 2 by the Navy’s NATO SEASPARROW Program Office (PMX-312), the milestone represents a doubling of deliveries since the program reached its 500th missile in 2025. The latest missile was produced for the 12-nation NATO SEASPARROW Consortium, with Raytheon, an RTX business, serving as the prime contractor.The Navy has not disclosed how the 1,000 missiles are divided among participating countries or how many have entered operational service.A more capable layer of ship defenseESSM is a ship-launched surface-to-air missile designed to intercept incoming aircraft, anti-ship cruise missiles, and other airborne threats. It provides individual warships with a layer of protection against attacks, complementing longer-range air-defense weapons.Block 2 introduces an upgraded guidance system featuring a dual-mode active and semi-active radar seeker. Earlier versions rely on the launching ship illuminating a target with radar during the missile’s terminal flight. The active seeker gives Block 2 the ability to detect and track targets independently during the final engagement phase.This reduces reliance on continuous radar illumination from the launching ship and gives its combat system greater flexibility when engaging multiple threats. The missile can also be quad-packed in the U.S. Navy’s Mk 41 Vertical Launching System (VLS), allowing compatible warships to carry four ESSMs in a single launcher cell.Red Sea operations highlight missile inventory pressuresThe production milestone comes as U.S. and allied warships continue to face the demands of defending commercial shipping and naval vessels against Houthi attacks in the Red Sea and Gulf of Aden.These engagements have exposed a practical challenge for modern warships: their missile magazines are finite. Even advanced destroyers can carry only a limited number of interceptors, while reloading vertical launch systems at sea is considerably more complicated than replenishing conventional ammunition.In January 2025, The War Zone reported that Vice Adm. Brendan McLane, then head of U.S. Naval Surface Forces, said the Navy had fired nearly 400 munitions during about 15 months of Red Sea operations. This included 120 SM-2 missiles, 80 SM-6 missiles and a combined 20 ESSM and SM-3 interceptors.The figures do not distinguish between ESSM Block 1 and Block 2, but illustrate the scale of defensive weapons expenditure during sustained operations. Maintaining production capacity is therefore important for replenish inventories and ensure ships can keep responding to aerial threats.A multinational production effortEstablished in 1968, the NATO SEASPARROW Project is one of NATO’s longest-running cooperative weapons programs. Its 12 members, Australia, Belgium, Canada, Denmark, Germany, Greece, the Netherlands, Norway, Portugal, Spain, Türkiye and the United States, collaborate on developing, producing and sustaining the missile system.Managed by the U.S. Navy’s PMX-312 office, the program brings together the participating navies and a multinational industrial base. Raytheon leads ESSM Block 2 production, supporting demand from the United States and its international partners.The 1,000th delivery is a significant manufacturing milestone for the consortium, demonstrating its expanding capacity to supply a widely used ship-defense system. As naval forces contend with increasingly sophisticated aerial threats, the ability to produce and replenish interceptors at scale remains an important part of maintaining maritime defense capabilities.