In October 2024, the aircraft carrier USS George Washington entered the U.S. Navy’s Yokosuka base (U.S. Fleet Activities Yokosuka) in Kanagawa Prefecture, Japan. The carrier is replacing the USS Ronald Reagan, which had been forward-deployed to Yokosuka since 2015. This marks the George Washington‘s second deployment to Japan, the first being in 2009. Notably, the vessel was equipped with a peculiar device. Resembling some sort of antenna at first glance, the device was installed in three locations: the starboard side, port side, and the aft section of the ship.
This device was first reported by The War Zone in 2021 and had been speculated to be related to electronic warfare. As of now, all carriers equipped with this device are deployed in the Pacific region. Based on the author’s observations, the carriers outfitted with this system include the USS George Washington, USS Carl Vinson, USS Theodore Roosevelt, USS Abraham Lincoln, and USS Ronald Reagan. Its true nature remained a mystery for some time, but during a media visit aboard George Washington in Yokosuka, the author uncovered the device’s true identity.
During the media visit to the flight deck, Naval News was able to photograph the mysterious device mounted on the port side. A nameplate attached to it read: “MK24 MOD0 Radar Sensor Assembly”. This confirmed that the device is not related to electronic warfare but is, in fact, a radar system.
In addition to its name, the nameplate also displayed the manufacturer of the device: Raytheon, now known as RTX, a major U.S. defense contractor. Naval News reached out to RTX to inquire on the “MK24 MOD0”. The company’s response, while limited, sheds some light on the role of the system:
“The system is part of the Carrier Self Defense system and aids CIWS and RAM for threat detection.”
In other words, this device appears to be a radar designed to detect threats at greater distances or to identify low-flying missiles, enhancing the effectiveness of systems like the Phalanx CIWS (Close-In Weapon System) and RAM (Rolling Airframe Missile). Considering the placement and angles of the devices, it is likely that they provide the carrier with nearly 360-degree threat detection coverage.
What stands out is the question of what this device was based on. Considering the rapid pace at which it was deployed on carriers, it seems more likely to be a system developed swiftly and reliably using an existing platform rather than one built entirely from scratch. Given that the manufacturer is RTX, a logical candidate for its foundation would be the APG-79 AESA radar. The size of the device, along with its configuration—apparently divided into two major components: the front antenna section and the processing unit behind it—further suggests that it may have been developed based on a fighter aircraft radar system. If this is the case, the radar is expected to have a detection range of approximately 150 km or more, and it is likely capable of detecting small, low-RCS (Radar Cross Section) missiles thanks to the use of X-band.
In brief, Naval News believes the new MK24 MOD0 radar system provides the aircraft carriers with a dedicated detection, tracking, cueing capability for self-defense against low observable, very low flying, and surface, threats. Given the advances in military capabilities of China, which the U.S. Navy is facing in the Indo-Pacific region, this system is an important upgrade to enhance aircraft carriers’ defense and ensuring their operational effectiveness.
