The USS Zumwalt (DDG-1000), a very large and stealthy Navy destroyer that has been beset by hurdles for much of its life, was put back in the water Friday after undergoing 14 months of work that saw its original and cost-prohibitive 155mm Advanced Gun Systems (AGS) replaced with launchers that will eventually fire Intermediate-Range Conventional Prompt Strike (IRCPS) hypersonic missiles.
Photos released by shipbuilder HII don’t show much of the IRCPS, as its position on the deck where the big guns once stood is covered. Still, Friday’s news was years in the making, as the Navy first announced plans to remodel its tiny Zumwalt class fleet to field next-generation hypersonic missiles in November 2021.
While the Zumwalt class was originally supposed to grow to 32 ships, the Navy ended up buying only three. Part of its original mission was gun fire support for amphibious operations, but the Navy never bought ammunition for its guns that would fulfill that role. This was largely due to the 155mm Long-Range Land Attack Projectiles (LRLAP) rounds fired from the ship’s two Advanced Gun Systems (AGS) costing $800,000 each.
Ship costs also soared over its lifetime, from an original estimated $1.3 billion per ship in 1998 to more than $9 billion by late 2020, according to the Government Accountability Office. The fact that only three ships were purchased also meant that all development and future upgrade costs would only be spread across a tiny fleet less than one-tenth the size of what was originally planned. Citing the ongoing nature of the work, Naval Sea Systems Command (NAVSEA) declined to confirm what the hypersonic upgrades will cost.
The future USS Lyndon B. Johnson (DDG-1002), the third and final ship in the class, will be the next to receive the IRCPS capability once Zumwalt’s work is done, NAVSEA told TWZ this week. LBJ wasn’t built with the AGS installed so less work will be needed to install the hypersonic missile capability, but the addition of the missiles will push the ship’s commissioning date from this year to 2027, according to NAVSEA.
The second Zumwalt class ship, USS Michael Monsoor (DDG-1001), is operating out of San Diego and will get its own hypersonic capability installed during a future yard modernization period, although NAVSEA did not clarify when that will take place. Navy budget request records for this fiscal year show the sea service is looking to have all three ready to go by Fiscal Year 2028.
While HII said they are not yet finished with the ship’s upgrade, Zumwalt’s eventual return to the fleet with a hypersonic missile capability marks the start of a potential redemption arc for the controversial class of ships. Partially due to its ammoless guns, the type has largely been one without a clear mission, despite the array of cutting-edge, albeit watered-down, technologies onboard.
But IRCPS could prove the Zumwalt’s worth, because the hypersonic missiles the class carries would be reserved for very high-value, well-defended targets. They will be loaded into the ship’s triple-packed Advanced Payload Module (APM) cannisters that are now situated where the guns once were, according to past TWZ reporting.
IRCPS and the U.S. Army’s hypersonic effort, the ground-based Dark Eagle Long Range Hypersonic Weapon (LRHW) system, are the same missile design and have a shared unpowered hypersonic boost-glide vehicle on top, with the only difference being how they are launched.
Such missiles will use rocket boosters to get its payload to the desired altitude and speed. At that point, the glide vehicle will separate from the rest of the booster and make its way toward its target through the atmosphere at very high speed along an unpredictable trajectory. Hypersonic velocity is defined as anything beyond Mach 5, but these weapons will far exceed that threshold.
But it remains unclear when Zumwalt will head out to sea with actual hypersonic missiles onboard. The U.S. Army got its first Dark Eagle missile launcher prototype in October 2021. It scrapped three test launches in 2023. The Navy and Army conducted a test fire in June but have not disclosed the results. Navy budget requests in recent years indicated that the sea services wants to fire hypersonics from Zumwalt by the end of 2025.
TWZ has previously reported on the benefits these speedy systems will provide:
“Boost-glide vehicles are also designed to be highly maneuverable, allowing for more unpredictable movements over the course of their flight compared to typical ballistic missiles, even those with advanced maneuverable reentry vehicles. This presents significant challenges for opponents in terms of detecting the incoming weapon and responding to it, including any attempts to intercept the threat. Giving an enemy less time to react also reduces their ability to relocate critical assets or just seek cover. All of this, in turn, means hypersonic weapons present an ideal choice for penetrating through even the densest air and missile defenses to strike high-value and potentially time-sensitive targets.”
Each of Zumwalt’s four large diameter tubes can fit three missiles, allowing for up to 12 in all, and the sea service will set requirements for how many missiles the ships will field for any given operation, USNI News’ Mallory Shelbourne reported in November 2024.
And while the Zumwalt class will be hypersonic-ready going forward, other facets of the ship remain unchanged. The Navy previously said the IRCPS capability doesn’t require extra space aboard the ship, and would instead take up the space previously used by the guns. DDG-1000s will continue to sport 80 Mk 57 Vertical Launch System (VLS) cells. A host of missiles could be loaded into the refitted Zumwalt, including SM-2 Block IIIAZ and Evolved Sea Sparrow surface-to-air missiles, as well as Tomahawk land-attack cruise missiles and potentially variants of the SM-6 missile family.
Despite the class’ capabilities being diluted over the decades, and while some external system add-ons have increased the class’ radar signature, its stealthy design could help the ships sneak within range of targets that sit inside enemy territory, something that would be critical to countering China’s long-range defenses in the Pacific.
The Zumwalt class has a huge, 14,500-ton displacement for a ship categorized as a destroyer. That is about one-third greater than Flight IIA Arleigh Burke class destroyers. It also boasts a stealthy design and multiple spectrum signature reduction – including electromagnetic emissions, radar, acoustic and infrared – that make it largely unprecedented for a ship of its size.
Zumwalt can also generate a gaudy 78 megawatts of electricity, enough to power nearly 10,000 average American homes. And even while speeding along at 20 knots, the ship class still holds a sizable 58 megawatts of reserve power. The destroyer’s cutting-edge Integrated Power System means enough power has been kept in reserve to provide current to next generation radar systems and directed energy weapons.
Still, with just three ships in the class, all packed with unique hardware, the cost of sustaining and upgrading these ships, including its stealthy features, will be hefty over time. There is talk of potentially replacing its proprietary radar and combat system with versions of the Enterprise Air Surveillance Radar (EASR) and Aegis Combat System to help with sustainment.
While it has ventured into the western Pacific, the class has not been on a traditional cruise. But now that Zumwalt is approaching a final baseline configuration, nearly a decade after it was commissioned into service, Navy brass are hoping it can be a next-level contributor to the fleet, even if that capability has come relatively late in DDG-1000’s life.
Contact the author: geoff@twz.com