A vertical launching system (VLS) is an advanced system for holding and firing missiles on mobile naval platforms, such as surface ships and submarines. Each vertical launch system consists of a number of "cells", which can hold one or more missiles ready for firing. Typically, each cell can hold a number of different types of missiles, allowing the ship flexibility to load the best set for any given mission. Further, when new missiles are developed, they are typically fitted to the existing vertical launch systems of that nation, allowing existing ships to use new types of missiles without expensive rework. When the command is given, the missile flies straight up long enough to clear the cell and the ship, and then turns on course.