Conventional Prompt Strike missiles are physically too large for the Navy’s standard vertical launch cells of the Navy, and that alone is determining the way some warships are being redesigned beginning with the deck. The size factor is: a boost-glide hypersonic missile requires a big-diameter rocket booster and a long canister, and that item can not fit into a widely-used Mk 41 cell of the fleet. The larger peripheral launch cells of the Zumwalt class had not been made on the basis of something in this diameter group.
CPS is the hypersonic, non-nuclear attack project of the sea service that is based on the common design with the army. The system takes advantage of a two-stage solid rocket booster to launch a maneuvering glide vehicle to the upper atmosphere and releases it to travel at hypersonic speed towards a target. Reducing that to the terms of ship integration, the weapon is not merely “a missile” but a long, heavy all-up-round that requires a launch tube with an appropriate internal diameter, structural support, and exhaust management. The Navy strategy is constructed with a two-stage booster with the Common Hypersonic Glide Body, a construction which, by definition, imposes a lower limit on the size of launchers.
It is the reason why the Zumwalt-class destroyers turned into the first apparent surface nominees. The central mission of their origin was founded on two massive Advanced Gun System turrets, which only ended up without any viable source of ammunition, leaving the giant available space in the front hull. Instead of putting CPS into naval missile farms, the Navy can rack AGS mounts and mount the intentional launchers in the locations of the guns and transform idle real estate into a completely new form of magazine.
The launcher that the Navy has settled on is the Advanced Payload Module which is basically a collection of over-sized vertical tubes that are customized to the weapon. In an interview with the Navy information office in 2021, it was said that the service only plans to fit conventional Prompt Strike (CPS) Hypersonic Missiles in the AGS turret openings, and not a complete internal rearrangement. The identical letter associated the timeline with the modernization availability windows: The DDG 1000 Dry-Docking Selected Restricted Availability (DSRA) will start in FY 2024. Those words are important since they disclose the fundamental engineering philosophy: CPS is the head of ship design, not vice versa.
The problem of size begins with the booster. A dimensional hint that has been much quoted is that the hypersonic booster of the Navy is almost 3 feet in width which puts standard cells at a glance out of the reckoning, since it is the uniformity that makes them flexible rather than an increase in diameter. The effect in the real world is that the “addition of hypersonics” to the sea is not the equivalent of loading a new rounds but rather of planting an industry-scale tube farm- digging steel, redistributing weight, shuffling services, and redesigning the deckhouse interfaces to new safety regulations.
With Zumwalt, the limitations can be handled since the volume and electrical margin of a typical experimental design are already in place, such as an internal power system and much larger hull than legacy destroyer. It was constructed with two large gun turrets and deep magazines; a replacement of that design with fewer and larger missile tubes is structurally invasive, yet not spatially constrained. Even the existing missile battery of the class the Mk 57 Peripheral Vertical Launch System is outboard in distributed modules and this means that the central volume of the ship is relatively clearer than many of other combatants.
The same physics is a fleet design problem in Arleigh Burke destroyers. The combat capability of Burke-class ships is based on dense Mk 41 arrays that have the capacity to contain a wide variety of missiles. To put a few huge tubes where there used to be meaningful numbers of those cells is not a simple upgrade; it is a trade of magazine geometry which resonates in mission loadouts, internal layout, and topside balance. That is, hypersonic integration is not so much about software as it is the harsh reality of having to fit a very large rocket into the ship designed to fit the smaller ones.
Giant launch tubes are thus no style choice and no program anomaly. They are the inevitable hardware by-product of a boost-glide weapon requiring a large booster, a large canister and in-board launch facilities designed to support both.
