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U.S. Army Receives First Sentinel A4 LRIP 2 Radar for 360-Degree Cruise Missile and Drone Defense.
Lockheed Martin delivered the first Sentinel A4 radar from LRIP 2 to the U.S. Army on Feb. 2, 2026, alongside completion of the first phase of IOT&E. The milestone matters because the A4’s 360-degree AESA coverage is designed to help Army air defenders spot and track cruise missiles, drones, and RAM threats earlier, while the program moves closer to a full-rate production decision.
On February 2, 2026, Lockheed Martin announced it had delivered the first Sentinel A4 radar from Low-Rate Initial Production (LRIP) 2 to the U.S. Army and completed the first phase of Initial Operational Test and Evaluation (IOT&E). The development comes as U.S. formations adapt air defense and base protection to a threat mix that now combines cruise missiles, drones, helicopters, fixed-wing aircraft, and rockets, artillery and mortars. With LRIP hardware moving into operational testing and fielding pathways, the program is entering the phase that shapes the full-rate production decision.
Lockheed Martin delivered the first Sentinel A4 radar from LRIP 2 to the U.S. Army and wrapped IOT&E phase one, marking a concrete step toward fielding a 360-degree sensor built to track drones, cruise missiles, aircraft, and RAM threats (Picture Source: Lockheed Martin)
The delivery marks the first of 19 LRIP 2 systems planned in this production lot, linking factory output directly to the U.S. Army’s evaluation and fielding tempo. Lockheed Martin indicated that IOT&E Phase I has been completed, an early milestone that helps validate performance and suitability before the program transitions to full-rate production. More than a symbolic handover, this step signals the radar is being assessed within the Army’s operational framework, where integration, data quality, and availability become as critical as raw detection performance.
Sentinel A4 is intended to replace the currently fielded Sentinel A3 radar with a modern 360-degree Active Electronically Scanned Array (AESA) sensor designed to counter a wide range of threats. In practical terms, full-circle coverage reduces blind sectors and supports continuous surveillance against targets approaching from unexpected azimuths, including low-altitude systems that attempt to exploit terrain masking or congested airspace. Lockheed Martin also emphasizes that Sentinel A4 is designed for complex environments where multiple threat types can appear quickly and simultaneously.
A key technical and operational point highlighted by the company is the radar’s open-architecture approach and its ability to connect across multiple command-and-control networks. During IOT&E Phase I, Sentinel A4 integrated with Forward Area Air Defense Command and Control (FAAD-C2), an outcome presented as validation of interoperability rather than a standalone sensor demonstration. That detail matters because modern short-range air defense is increasingly a network problem: sensors must distribute tracks rapidly and reliably to the nodes that manage engagements and airspace coordination.
The program’s mission set reflects the reality that defended areas are rarely challenged by one category of threat at a time. Lockheed Martin states Sentinel A4 is built to counter cruise missiles, unmanned aircraft systems, helicopters and fixed-wing aircraft, while also addressing rockets, artillery and mortars. This breadth positions the radar as a single sensor layer intended to contribute both to air surveillance and to counter-indirect-fire awareness, an increasingly valuable combination when adversaries seek to saturate defenses and force repeated disruption of command posts, logistics sites, and forward operating locations.
Beyond expeditionary force protection, Sentinel A4 is also being positioned within homeland security integration. In a separate Lockheed Martin newsroom communication dated February 2, 2026, the company linked Sentinel A4 delivery to the National Capital Region, underscoring the radar’s role in layered defense where continuity of surveillance and dependable data flow are central requirements. Framing the system in both forward-area and homeland contexts helps explain why interoperability claims and test milestones carry weight well beyond the radar community.
The significance of Sentinel A4 lies in shortening the sensor-to-decision timeline. Continuous 360-degree surveillance supports earlier detection and more stable track management, which in turn can improve cueing and coordination within layered defenses when faced with drones, cruise missiles, and manned aircraft in the same operating area. For U.S. planners, the strategic implication is a scalable modernization path: fielded LRIP systems support operational testing and refinement of tactics, while building the industrial and training base needed to expand coverage across formations and priority sites.
The first LRIP 2 Sentinel A4 delivery and completion of IOT&E Phase I move the program into the stage where interoperability, availability, and real operational integration determine readiness for full-rate production. By replacing Sentinel A3 with a 360-degree AESA sensor designed to address both air-breathing threats and rockets, artillery and mortars, the U.S. Army is reinforcing a defense posture shaped by saturation and compressed warning times. The pace of LRIP deliveries and follow-on testing will now decide how quickly this radar becomes a common sensor layer for U.S. force protection and priority homeland defense missions.