The three Zumwalt-class destroyers currently in service with the U.S. Navy could receive radar systems initially produced for the cancelled Constellation-class frigates. A Raytheon executive told Naval News that the possibility of replacing the AN/SPY-3 radar currently fitted on the Zumwalt-class with the AN/SPY-6 is being considered.
The Zumwalt-class guided missile destroyers are known for their distinctive hull design, which places a strong emphasis on stealth. They were originally conceived as platforms primarily tasked with providing naval surface fire support (NSFS) in littoral and land-attack operations. However, due to a significant reduction in the number of ships built, along with the soaring cost of the guided munitions intended for use with the 155mm Advanced Gun System (AGS), procurement of those rounds was ultimately cancelled. As a result, the class has increasingly diverged from its original operational concept.
At present, modifications are being carried out sequentially to remove the forward AGS turret and replace it with vertical launch systems (VLS) designed to accommodate the Conventional Prompt Strike (CPS) capability, which employs hypersonic glide vehicles (HGVs). The lead ship, USS Zumwalt, has already completed this conversion. The second ship, USS Lyndon B. Johnson, is currently undergoing modification at Ingalls Shipbuilding, while the third ship, USS Michael Monsoor, is scheduled to receive similar upgrades during its next planned maintenance availability.
Plans to replace the radar system on the Zumwalt-class first came to light in November 2022, when a Request for Information (RFI) was issued regarding a capability enhancement program known as the Zumwalt Enterprise Upgrade Solution (ZEUS). According to reporting to date, ZEUS includes the integration of the Surface Electronic Warfare Improvement Program (SEWIP), the undersea warfare combat system SQQ-89, and the Cooperative Engagement Capability (CEC). It also encompasses the replacement of the Raytheon-built AN/SPY-3 radar with the company’s AN/SPY-6.
The AN/SPY-6 is the latest generation of naval radar that Raytheon has begun delivering to the U.S. Navy. It is planned for installation across a wide range of U.S. Navy platforms, including Aegis destroyers, aircraft carriers, amphibious assault ships, and even the proposed Trump-class battleships. The SPY-6 is a modular radar system, in which a large radar array is constructed by combining square Radar Modular Assemblies (RMAs), each measuring two feet (approximately 60 cm) per side and functioning as individual transmit/receive modules.
SPY-6 Backfit for Zumwalt-class
Regarding recent developments concerning the potential backfit of SPY-6 onto the Zumwalt-class, Jennifer Gauthier, Vice President of Naval Systems & Sustainment at Raytheon, stated in an interview with Naval News in Tokyo, Japan, that “we are currently in discussions with the U.S. Navy and nothing has been decided,” before elaborating as follows:
“I will tell you that Raytheon has recently gotten funding from the United States Navy for some development work associated with the combat management system of the Zumwalt. And that combat management system work will help its ability to integrate with the SPY-6. We have also the first certified, classified, what we call a software factory for Zumwalt. And what that means is we have the ability to upload software directly onto the ship, instead of sort of the longer time that it typically takes. So Zumwalt continues to go through development work. We continue to put resources into Zumwalt. And we are optimistic that the Navy will make a choice to back fit Zumwalt with SPY-6.”
Jennifer Gauthier, Vice President of Naval Systems & Sustainment, Raytheon
In addition, according to John Tobin, Associate Director for International SPY Radar Programs at Raytheon, the SPY-3 is roughly comparable in size to the SPY-6(V)3 configuration, which consists of nine RMAs. Therefore, if a backfit were to be implemented, it would most likely involve the SPY-6(V)3 variant. He further noted that such radars could potentially be repurposed from units originally manufactured for the Constellation-class frigate program, which was subsequently cancelled.
“The Zumwalt should be back fit, and it would be the SPY-6(V)3. You can see that the Constellation-class frigate was cancelled by President Trump. But those radars (SPY-6(V)3) exist.”
John Tobin, Associate Director for International SPY Radar Programs, Raytheon
The U.S. Navy cancelled the Constellation-class frigate program on November 25, 2025. FF(X) is meant to replace Constellation-class / FFG(X) frigates but these vessels, based on the much smaller Legend-class cutters of the U.S. Coast Guard, will not be fitted with SPY-6 radars. In addition to the radar arrays, other systems meant to go on the cancelled frigates have already been produced various contractors, such as the sonar systems.
