A video frame showing the new guided missile destroyer USS Zumwalt on its way to its new homeport in San Diego, California. Photo: WikiCommons

Hypersonic missiles will be installed on three US destroyer-class ships this month as Washington moves to increase its capabilities at sea and counter possible Chinese and Russian threats.

Three of the US Navy’s troubled Zumwalt-class destroyers will be fitted with the hypersonic missiles, replacing the ships’ two massive 155mm Advanced Gun Systems (AGS).

Upon finishing these changes in 2025, the Zumwalt-class would be the first US naval platform to be armed with hypersonic weapons.

The conversion aims to make the futuristic stealth vessels into blue-water strike platforms, in contrast with their original purpose of operating in the littorals and supporting forces ashore with guided rounds from their dual 155mm guns. 

The Zumwalt class was originally built around two 155mm AGS weapons. However, the high cost of the AGS’ guided rounds at US$1 million each – approaching that of a Tomahawk cruise missile – stopped the US Navy from mass procurement.

Also, the proliferation of littoral defenses such as anti-ship missile batteries, naval mines and coastal submarines may have made the Zumwalt destroyers too vulnerable for shore bombardment roles. 

Replacing the twin AGS weapons, the Zumwalt class would be fitted with at least two sets of hypersonic missile tubes inserted on the port and starboard sides of the ship. Replacing the Zumwalt’s AGS mounts with hypersonic missile tubes gives the class strategic-level capabilities, while preserving its 80 existing vertical launchers, which are vital for air defense and anti-ship missiles. 

These missile tubes would be based on the Multiple All-up-round Canisters (MAC) system installed on four Ohio class nuclear guided-cruise missile submarines. Aboard the Zumwalt class, these MACs could be loaded with three Common Hypersonic Glide Body (C-HGB) missiles per tube. 

However, the US Navy has not given the exact numbers of how many tubes or hypersonic missiles the Zumwalt class will carry.

The Zumwalt-class destroyer USS Michael Monsoor. Photo: Naval News

Advanced technologies

The US Navy may have planned to repurpose the Zumwalt class from being a failed shore bombardment platform into a hypersonic weapons launcher to continue utilizing the advanced technologies featured in the class. These technologies include its stealth characteristics, radars, electric propulsion systems and processing capabilities.

However, this may also be a move to save what was already an unfeasible design in the first place. 

The Zumwalt’s tumblehome stealth hull could potentially become unstable in high seas and can be detected with low-frequency radar. Also, no close-in weapons systems (CIWS) were installed on the class to maximize its stealth features, making it vulnerable to air and anti-ship missile attacks. 

In addition, the high cost of $4.24 billion per unit for only three ships means there might not be enough Zumwalt ships to fulfill US Navy mission requirements.

Such an approach to weapons design may reflect the US tendency to spend exorbitant amounts on over-engineered and overly-complex designs which promise to do so much yet cannot be mass-produced, due to high costs.

These designs may also be aimed at accomplishing too much that they end up not being specialized for any role. 

That said, it may be more practical for the US Navy to install hypersonic weapons on cheaper, more numerous assets.

These could include the upcoming Constellation-class frigates, which are designed to take up the role of inexpensive general-purpose warships that can be bought in large numbers, in order to complement the capabilities of larger and more capable ships such as the Arleigh Burke and Zumwalt class. 

While hypersonic weapons are still in their infancy and therefore have high costs at present, it can be reasonably expected that costs will sink once the technology matures and production rates pick up, allowing more warships to be armed with them. 

Also, it could be more feasible to start with a new ship class designed from the outset to be armed with hypersonic missiles. While the Zumwalt class is planned to be equipped with hypersonic weapons, their high unit cost, unproven technology and small number may restrict their roles into being technology demonstrators for more feasible and sustainable ship designs. 

That said, the US Navy’s planned Next-Generation DDG (X) destroyers are expected to be equipped with hypersonic and directed energy weapons, and feature key technologies featured on the Zumwalt class, such as the electric propulsion and electricity generation systems. 

Construction of the new class is planned to start in 2028 and may be substantially cheaper per unit than the Zumwalt class, with a cost estimate of $1 billion per hull.