Mark 41 Vertical Launching System

On 12 October 2016, USS Mason (DDG-87) was targeted by missiles fired from Yemeni territory while operating in the Bab el-Mandeb strait.[3] Mason was not hit by the two missiles, which were fired from near the city of Al Hudaydah.[3] While the Navy is not certain whether the first incoming missile was intercepted or it just fell into the sea, officials claim Mason successfully intercepted the second missile at a distance of about 8 miles (13 km),[4] marking the first time in history a warship destroyed an inbound anti-ship missile with a SAM in actual self-defense and the first time the Mk41 VLS did so.

The Mk 41 is capable of firing the following missiles:[5][2]

• RIM-66 Standard
• RIM-156 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
• RIM-162 ESSM
• Joint Strike Missile
• AGM-179 JAGM
• CAMM (CAMM, CAMM-ER, CAMM-MR)

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][6] Some munitions under development such as CAMM-MR are planned to be dual-packed with two missiles sharing a single canister enabling larger and longer range munitions to be carried in greater quantity.[7] 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 56 VLS is an evolution of the tactical length Mk 41 VLS which is a smaller version of the strike length Mk 41 used on Arleigh Burke-class destroyers.

The Mk 57 Peripheral Vertical Launch System (PVLS) used on the Zumwalt-class destroyers is composed of much larger VLS cells capable of venting much larger volume and mass of exhaust gasses (mass flow rate), but is an evolution of the smaller unarmored Mk 56 VLS. The Mk 57 PVLS are designed to be installed on the ship periphery with armor on the inboard boundary, instead of in centralized magazines used in the Mk 41.

Developed by Raytheon, Mk 57 provides backwards compatibility with existing missiles while allowing new missiles with significantly increased propulsion and payloads. While allowing for larger missiles than the Mk 41, the primary improvement of Mk 57 is its exhaust gas management system which can accommodate new missile designs having up to 45 percent greater rocket motor mass flow rate than that of Mk 41.[8] 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.