Authors: Li Penghan, Yang Donglin, Yu Chengnong, College of Military and Political Basic Education, National University of Defense Technology
The history of the development of the Close-In Weapon System (CIWS) dates back to the 50s of the 20th century, when with the development of aviation technology and missile technology, ships faced increasingly serious air threats, especially from anti-ship missiles. In order to counter these threats, the navies of various countries began to research and develop automatic defense systems capable of intercepting incoming targets at extremely short distances. In the 21st century, the development of short-range defense weapon systems has become even more rapid. Modern short-range defense weapon systems not only have a higher rate of fire and accuracy, but also incorporate advanced electronic warfare capabilities and information technology. These systems can achieve information sharing and coordinated operations with other combat systems through the network, which greatly improves the defense capability of the entire fleet. In addition, with the development of unmanned technology and artificial intelligence technology, short-range defense weapon systems have also ushered in new development opportunities. The unmanned short-range defense system can achieve faster response and more accurate strikes, while the application of artificial intelligence technology can improve the autonomous decision-making and combat capability of the system. MK15 "Phalanx" short-range defense weapon system is an automated defense system developed by the United States military industry, which is mainly used for self-defense of ships against enemy threats at short distances, such as anti-ship missiles, unmanned aerial vehicles, helicopters, etc. In the Red Sea region, the Houthis pose a serious threat to American ships sailing in the region. The Houthis possess a certain number of weapons such as anti-ship missiles, drones, and suicide boats, which are characterized by high speed, high accuracy, and suddenness, and pose a serious challenge to the safety of American ships. In response to these threats, the US Navy has deployed the MK15 short-range defense weapon system on ships in the Red Sea region. The system is capable of quickly reacting after the launch of enemy weapons, intercepting and destroying approaching enemy targets. In the event that the Houthis pose a threat to American ships, the MK15 system became an important means of defense for the US Navy in the region.
Figure 1 The Phalanx short-range defensive weapon system is firing
Fully automated defense performance is ahead of the curve
The "Phalanx" short-range defense weapon system is designed to carry out fully automatic defense, that is, after the radar is given the information of the target, it can completely search, track, assess the threat of the target, lock on, and fire. The advantage of this design is that it is easy to install, the carrier only needs to provide power, does not need to be integrated with the ship's combat detection system to operate, and the deck is installed in a position that ensures sufficient structural strength. Due to the limitations of the carrier, the radar of the Phalanx system can only share the same maneuver/pitch angle with the cannon, and cannot independently perform wide-area search, so the system can only attack one target at a time after it is turned on. This shortcoming has been improved in recent years by integrating it with the Aegis combat system. The Phalanx is equipped with a 20mm six-barreled M61A1 Vulcan Gatling cannon, which and its derivatives have long been one of the main melee weapons of the United States Air Force fighters, such as the F22 and other fighters used in the M61A1 type. The reason why the "Phalanx" is called the last line of defense of the battleship is that the most critical thing is its reaction time and multi-angle defense capability: according to the data of the US Navy, the search and tracking radar equipped with the "Phalanx" is about 2 seconds from detecting the target to the start of the attack, and at the moment of attack, the fire control radar will continue to track the current position of the target and the position of the ammunition to detect the difference between the two and correct the firing angle, which is the so-called"Closed-loop fire control". The dedicated gun mount is the MK-72, a highly flexible gun mount that can rotate at 115°/s driven by servo motors and tilt angles between -25° and +85°. The search radar can provide the computer with data such as the target's bearing, distance, speed, navigation and altitude, while the tracking radar will keep tracking the target until the CIWS confirms that the target is no longer a threat.
Figure 2 Model diagram of the MK15 "Phalanx" close defense system
Value in modern naval warfare
In modern naval warfare, the enemy often uses high-speed, high-precision weapons such as anti-ship missiles to strike at ships. The MK15 system is capable of intercepting such threats in a very short time, increasing the survivability of the ship. At the same time, the MK15 system can be used in conjunction with other anti-aircraft weapon systems, such as the Aegis system, to form a multi-layered air defense network and increase the overall defense capability of the formation. Track multiple targets at the same time and prioritize the most threatening targets to effectively respond to saturation attacks. It is worth mentioning that as the originator of the ship's close defense, the powerful firepower of the MK15 system has a certain psychological deterrent effect on the enemy and reduces the enemy's determination to attack.
For the defenders, the successful application of this system will prompt countries to develop similar close-range defense weapons in order to increase the survivability of their fleets. For the attacker, the emergence and development of this system has transformed air defense operations from traditional long-range interception to close-range interception, emphasizing the improvement of defense capabilities. It is undeniable that the maritime security situation has become more complex: with the popularization of close-range defense weapon systems such as the MK15, the maritime security situation will become more complex, and countries need to strengthen maritime security cooperation and communication while developing defensive weapons. With the continuous development of science and technology and the emergence of new threats, the MK15 short-range defense weapon system also needs to be continuously upgraded and improved. In the future, the system may incorporate more advanced radar technology, fire control systems, and ammunition technology to improve its detection accuracy, strike capabilities, and survivability. With the development of artificial intelligence technology, the MK15 short-range defense weapon system is expected to achieve a more intelligent combat mode, further improving its combat efficiency and defense capabilities.
Figure 3 The MK15 close defense system equipped on the ship
The work is not significant and the accidental injury is repeated
Although the Phalanx close defense system was boasted so miraculously by the United States, it was a big disappointment in actual performance. In the nearly 30 years of service, the Phalanx system has not been without opportunities to perform its unique skills, but in several actual battles, it is either not ready, or it has failed, and nothing has been gained, making the "last line of defense" unworthy of its name. On May 17, 1987, during the Iran-Iraq War, two Exocet missiles hit the US Perry-class frigate Stark. The battle coincided with the ship's Phalanx system being "malfunctioning". The radar of the Phalanx system, which is the ship's main anti-missile mission, failed to even detect the incoming missile, and as a result, the Flying Fish missile penetrated the side of the ship without hindrance and seriously damaged it. On 12 October 2000, the USS Cole, the most elite Ali Burke-class destroyer in the United States, was killed by a small rubber boat loaded with explosives while docking at the port of Aden, Yemen, while refueling. Due to the proximity, neither the main gun nor the anti-ship missile can be used, and the only hope is in the MK15 Phalanx system. Unfortunately, it was too careless, and the two phalanx systems were not prepared, and they could only watch as the dinghy tore a large hole in the port side, killing 17 sailors and wounding 33 on board. To this end, the US Navy ordered to bring large-caliber machine guns to the deck to prevent similar incidents, which showed from the side that it did not trust the capabilities of the Phalanx system. In the case of the Israeli Saar-5 frigate in the missile attack on Allah, the Phalanx system on board the "Harnett" continued its tradition of "battlefield inaction". According to the Israeli Navy's explanation, the ship's protection system was turned off to avoid affecting its own warplanes in the nearby airspace. In 1996, when the frigate "Yukiri" of the Japanese Maritime Self-Defense Force was conducting a live-fire air defense exercise, the "Phalanx" did not hit the target tow, but instead hit the A-6 fighter jet towing the target with a 5.5-kilometer cable, and the two pilots were rescued by parachuting into the sea. The consequences were even more serious in the 1994 Han Kuang exercise in Taiwan, the Phalanx system on the Taiwan Navy's frigate "Chenggong" also shot down the target tower by mistake, but the four people on board failed to escape and all were killed. As the most reliable "guard" of warships, the phalanx system has repeatedly made mistakes, whether it is due to human reasons or its own design flaws, so that the navies of various countries will inevitably have doubts about its actual performance.
Fig.4. Schematic diagram of the structure of the MK15 "Phalanx" close defense system
As the world's first shipborne close defense system to be successfully put into service, the "Phalanx" has its own glorious track record, with the highest shooting accuracy, the largest number of equipment (870 sets have been produced, belonging to the navies of 21 countries), the largest number of destroyed targets, the most compact structure, and the largest number of photogenic appearances...... MK15 short-range defense weapon system responds quickly, has good versatility, and can implement a short-range defense weapon system that can automatically search, detect, evaluate, track and attack targets, it adopts a three-in-one structure of search radar, tracking radar and artillery, and all its combat functions are automatically completed by high-speed computer control, without manual operation, and the response speed is extremely fast, and the tracking distance is 10 kilometers. Although there are shortcomings such as accidental injuries, insufficient power, and fighting alone, it has opened a precedent for the high-velocity close-in defense system of the transfer tube, and many countries have launched similar products with this, such as Russia's AK630 and Italy's "Jushu". It demonstrates the important strategic value of modern naval warfare: in the future, the development of close-range defense weapons will be the focus of attention of navies of various countries, and it will also affect the changes in the maritime security landscape. In developing naval forces, the state pays attention to the development of such weapons, strengthens relevant technical research and equipment construction, and improves the survivability and combat effectiveness of the navy as a powerful means.