or carrier strike group. There is a view among some military pundits that modern anti-ship weapons systems, such as torpedoes and missiles, or even ballistic missiles with nuclear warheads have made aircraft carriers and carrier groups too vulnerable for modern combat. like the German U24 of the conventional 206 class which in 2001 "fired" at the Enterprise during the exercise JTFEX 01-2 in the Caribbean Sea by firing flares and taking a photograph through its periscope or the Swedish Gotland which managed the same feat in 2006 during JTFEX 06-2 by penetrating the defensive measures of Carrier Strike Group 7 which was protecting . Description Structure Carriers are large and long ships, although there is a high degree of variation depending on their intended role and aircraft complement. The size of the carrier has varied over history and among navies, to cater to the various roles that global climates have demanded from naval aviation. Regardless of size, the ship itself must house their complement of aircraft, with space for launching, storing, and maintaining them. Space is also required for the large crew, supplies (food, munitions, fuel, engineering parts), and propulsion. US aircraft carriers are notable for having nuclear reactors powering their systems and propulsion. The top of the carrier is the flight deck, where aircraft are launched and recovered. On the starboard side of this is the island, where the funnel, air-traffic control and the bridge are located. The constraints of constructing a flight deck affect the role of a given carrier strongly, as they influence the weight, type, and configuration of the aircraft that may be launched. For example, assisted launch mechanisms are used primarily for heavy aircraft, especially those loaded with air-to-ground weapons. CATOBAR is most commonly used on US Navy fleet carriers as it allows the deployment of heavy jets with full load-outs, especially on ground-attack missions. STOVL is used by other navies because it is cheaper to operate and still provides good deployment capability for fighter aircraft. Due to the busy nature of the flight deck, only 20 or so aircraft may be on it at any one time. A hangar storage several decks below the flight deck is where most aircraft are kept, and aircraft are taken from the lower storage decks to the flight deck through the use of an elevator. The hangar is usually quite large and can take up several decks of