Mark 41 Vertical Launching System

The Mk 41 is capable of firing the following missiles: RIM-66 Standard, RIM-67 Standard, RIM-161 Standard Missile 3, RIM-174 Standard ERAM, RGM-109 Tomahawk, RUM-139 VL-ASROC anti-submarine missile, RIM-7 Sea Sparrow anti-air missile, and RIM-162 ESSM.[2] The missiles are pre-loaded into "canisters", which are then loaded into the individual "cells" of the launcher. The ESSM is loaded in a quad-pack with 4 missiles in one Mk 25 canister, older types of 8 cell modules are not able to use ESSM.[2][3] Launcher cells are fitted to ships in 8 cell modules (2 rows of 4) that share a common uptake hatch (exhaust system) sited between the two rows.[2] The Mk 41 VLS adopts modular design concept, which result in different versions that vary in size and weight due to different "canisters" in various modules. The height (determining missile length) of the launcher comes in three sizes: 209 inches (5.3 m) for the self-defense version, 266 in (6.8 m) for the tactical version, and 303 inches (7.7 m) for the strike version. The empty weight for an 8-cell module is 26,800 pounds (12.2 t) for the self-defense version, 29,800 pounds (13.5 t) for the tactical version, and 32,000 pounds (15 t) for the strike version.[2] Ticonderoga cruisers and Arleigh Burke destroyers up to DDG-78 have a Strikedown module fore and aft, which consists of five cells and a collapsible crane for assisting with replenishment at sea. As replenishment of large missiles at sea was later seen as impractical and dangerous, Strikedown modules fell out of use on newer ships.[2]

Mk 57 VLS

The Mk 57 VLS is an evolution of Mk 41 VLS. Unlike the Mk 41, the Mk 57 is designed to be installed on the ship periphery instead of in centralized magazines. Developed by Raytheon, it provides backwards compatibility with existing missiles while allowing new missiles with significantly increased propulsion and payloads. While allowing for slightly larger missiles than the Mk 41, the primary improvement of Mk 57 is its exhaust gas management system that can accommodate new missile designs having up to 45 percent greater rocket motor mass flow rate than that of Mk 41.[4] The unique symmetric geometry of the U-shaped gas management system facilitates the egress of gases, while minimizing flow into adjacent cells and reversed flow into the active cell. Another advantage is the elimination of the water deluge system, which is used to cool the missile canister in the event that the missile restraint bolts do not release after rocket motor ignition. Elimination of the water deluge system significantly reduces maintenance and personnel requirements, and protects against accidental missile wet-down.