The U.S. Navy is in the process of exploring options to replace Raytheon's AN/SPY-3 radar on its three still not yet operational Zumwalt class destroyers. The only option we know definitively to be under consideration is a variant of the Enterprise Air Surveillance Radar, or EASR, but the Navy has indicated that there are others. EASR is another Raytheon product that is already slated to go onto a number of the service's new ships, including all future Ford class aircraft carriers from CVN-79 on and the forthcoming Constellation class frigates, previously known as FFG(X). Combined with the stealthy destroyers' other advanced and largely unique combat systems, a new, more powerful radar could significantly expand their capabilities, which were grossly watered-down years ago as part of cost-cutting efforts.
A spokesperson for Naval Sea Systems Command confirmed to The War Zone that "the Navy is exploring several alternatives to sustain air and surface search capability aboard the Zumwalt class ships" on Oct. 15, 2020. That same statement said that "no decision has been made at this time" as to how the service will necessarily proceed. The first-in-class USS Zumwalt has already received its combat systems, but the second and third ships in the class, the USS Michael Monsoor and the future USS Lyndon B. Johnson are in the process of being fitted out. As such, all three could need to have their existing removed in order to recieve new ones.
As originally designed, the Zumwalt class destroyers, also often referred to by the hull number of the first-in-class USS Zumwalt, DDG-1000, were to have a Dual Band Radar (DBR) installation. This would have combined two separate radar systems, the AN/SPY-3, an X-band active electronically scanned array (AESA) type, with the Lockheed Martin AN/SPY-4, an S-band volume search radar. In an air and missile defense scenario, the idea was that the AN/SPY-3 would be used for horizon search, to provide high-fidelity target tracks and otherwise help direct those weapons to impact, while the AN/SPY-4 would offer long-range search, tracking, ballistic missile discrimination, and some additional abilities to communicate with intercepting missiles. The two radars would perform these functions simultaneously, with their information fused together, offering an impressive combined capability. The Zumwalts also feature a unique advanced command and control software and computing architecture, which you can read about more here. It was designed to make great use of the DBR configuration.
However, in 2010, the Pentagon made the decision to eliminate the AN/SPY-4, the larger of the two radar arrays, from the Zumwalt design, one of many cost-cutting measures that degraded the ship's overall capabilities. Instead, software was added to work with the AN/SPY-3 to allow it to perform the volume search function, as well. While the latter radar can now be used to cover some of the AN/SPY-4's tasks, it has nowhere near the performance that was supposed to come from the two radars operating in tandem.
It is worth noting that whether or not the DBR would have ultimately met the Navy's expectations is unclear. This paired radar system was also slated to go onto the Ford class aircraft carriers, but has suffered from repeated technical issues and other delays, which you can read more about in this past War Zone piece. As it stands now, only the first-in-class USS Gerald R. Ford
The AN/SPY-6(V)3, or another variant of the EASR, is certainly one of the most obvious choices as a replacement for the AN/SPY-3 on the Zumwalts. Rich Calabrese, Lockheed Martin's Director of Surface Navy Mission Systems, recently told The War Zone that the Navy was considering doing just that as part of a larger interview that we will be publishing in the near term on that company's Aegis Combat System and what the future holds for it.
"They're looking at a back fit of an EASR radar, back to a DDG-1000 replacing the current radar," Calabrese said. "That would be a pretty straightforward approach."
Derived from the AN/SPY-6(V)1 Air and Missile Defense Radar (AMDR) developed for the Flight III Arleigh Burke class destroyers, EASR, though smaller, is made up of the same modular Radar Modular Assemblies (RMA). The AMDR has four arrays, each with 37 RMAs, with the AN/SPY-6(V)3 has three nine-RMA arrays.
Each two-foot-by-two-foot-by-two-foot cube-shaped RMA is essentially its own AESA radar. This allows them to perform individual functions independently or work together to focus on a single task, providing immense flexibility and high-fidelity over a great range.
In addition, the modularity that the RMAs offer means that EASR arrays are inherently scalable, as shown in the Raytheon product video below, and more easily configured to fit different physical space and power requirements. The DDG-1000s were built with huge spaces, that now sit vacant, for the AN/SPY-4 radars, and have immense power generating capabilities.
The RMAs can be removed or installed individually, as well, reducing the time and costs associated with carrying out certain preventive maintenance tasks and other repairs. This means more reliability, upgradability, and up-time for the radar system as a whole.
EASR, which you can read more about in this past War Zone piece, is already becoming extremely popular within the Navy. In addition to the rest of the Ford class, the AN/SPY-6(V)3 will also be a key sensor on the future Constellation class frigates, previously known as FFG(X). A version of the radar with a single nine-RMA array on a rotating mount, designated the AN/SPY-6(V)2, will also go onto the future USS Bougainville, the first ship in a new subclass of the America class amphibious assault ship, as well as the forthcoming Richard M. McCool Jr., a San Antonio class landing platform dock amphibious ship. The upcoming Flight II San Antonio class ships will also have this radar.
Versions of this radar are slated to be back-fitted onto other members of the America and San Antonio classes, as well as other existing ships as time goes on. In July, the Navy announced that it was buying an AN/SPY-6(V)2 for installation on the Nimitz class aircraft carrier USS John C. Stennis.
Another option for the Zumwalts might be the AN/SPY-6(V)4, another fixed-face member of this family that occupies a space between the AMDR and the existing EASR variants in terms of overall capability. This version has four arrays, just like the (V)1, but each with 24 RMAs, instead of 37. Raytheon developed this radar for the Navy to refit Flight IIA Arleigh Burke class destroyers.
The Navy has said that that is looking at multiple alternatives and Raytheon's competitors, chiefly Lockheed Martin, could very well be offering their own radars for the Zumwalts, as well. Lockheed Martin has already proposed using a version of its AN/SPY-7(V)1 Long Range Discrimination Radar (LRDR) as a replacement for the aging variants of the AN/SPY-1 on the Navy's Ticonderoga class cruisers.
The LRDR is presently slated to be the primary radar used at the future Aegis Ashore ballistic missile defense site in Hawaii. This radar was also set to be a component of Japan's Aegis Ashore systems, before that country canceled work on those sites entirely earlier this year. Lockheed Martin also says that variants of this radar will go onto future Royal Canadian Navy frigates, which will be based on the BAE Systems Type 26 design, as well as Navantia's future F110 class frigates for the Spanish Navy.
Whatever new radar the Navy picks could re-open a world of possibilities for the Zumwalts and could come along with other updates. As it stands now, among their many one-off design elements, these ships do not have the Aegis Combat System that is common across the Navy's surface combatant fleet. The ship's combat system is unique and runs on its own proprietary Linux-based software and advanced computing environment, known as the Total Shipboard Computing Environment (TSCE). Supporting an entirely separate combat system—adapting it for new weapons, hardware, and capabilities over time—is an incredibly complex and costly proposition. Switching over to Aegis for the ship's tactical applications, along with the new radar, could be part of an initiative to solve that glaring problem and it would make the DDG-1000s far more supportable over time.
Lockheed Martin's Calabrese specifically said his company has explored potential ways to give the Zumwalts at least an Aegis-like capability if the Navy were interested, especially as part of the decision to add new radars to the ships. "The DDG-1000 is the oddball out. We have ideas on how, again, leveraging the virtual Aegis Weapon System, you could bring Aegis capability to a DDG-1000," he explained.
"We've developed some concepts for [that approach] and that would be ready to introduce should the Navy have interest in doing that. But yeah, currently that's the sort of the odd duck out," he continued. "I look at DDG-1000 as an opportunity for further commonality because it is currently the 'one-off' of the combat systems in terms of being able to take advantage of synergies across the programs."
Exactly what the Navy expects its three Zumwalts to do will likely be an important factor in whatever course of action the service eventually decides to pursue. The ships are presently assigned to Surface Development Squadron One, a unit focused on exploring future surface warfare concepts of operation, and their actual operational role may be limited in the end. The extremely small size of the class makes it a very low-density, high-end asset to begin with. The Navy has already publicly gone back and forth over the years about the exact missions it wants these advanced warships to be able to carry out.
While a replacement radar could give the ships a boost in capability, other limitations remain. For one, the Navy still has no formal plans to acquire any ammunition for the two 155mm Advanced Gun Systems (AGS) on the Zumwalts, after deciding not to buy stocks of the exorbitantly priced Long Range Land Attack Projectile (LRLAP) in 2016. There are indications that the service may now be looking to modify these guns to fire new Hyper Velocity Projectiles, but whether or not that will actually happen, remains unclear. The first-in-class USS Zumwalt only fired its 30mm automatic cannons, meant for close-in defense and which were controversially installed in place of more powerful 57mm cannons—another cost-saving measure—for the first time in May.
These issues, along with the fact that Navy has resorted to bolting many types of antennas to its stealthy deckhouse—yet another cost-saving move—that diminishes the whole reason behind its elaborate design, underscores how big of a boondoggle the program has become. Now the ship's radars may get ripped out and replaced, and its combat system possibly as well, all before the ships ever set sail on an operational mission. All this has already come at a cost of over $26 billion for just three vessels.
While lessons need to be learned from this fiscal disaster, the fact that the Navy is getting serious about actually squeezing the most that it can out of these ships it has already invested so heavily in is encouraging, even if it means spending a bit more money to see that it happens.
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