Because of poor planning, Japan has decided to cancel the installation of two Aegis Ashore ABM (Anti-Ballistic Missile) systems. The decision to buy and install the two Aegis Ashore in two existing military bases was made at the end of 2017. This decision was encouraged by the fact that in 2016 the first Aegis Ashore system became operational in Romania. The second one became active by 2018 in Poland.
Unfortunately, Japan is not like Romania and Poland, two nations that suffered decades of brutal Russian occupation. Japan has prospered greatly under the protection of the American military after World War II and developed some bad habits when it came to defense matters. What killed the Aegis project were several of those bad habits. First, as defense officials were working out the details the soon found they had underestimated the cost of preparing the two Aegis Ashore sites. That cost was about 25 percent higher than estimated. Costs threatened to increase still more when civilians living near the two Aegis base areas discovered that there were side-effects from the use of Aegis missiles. Planners made some adjustments to the area Aegis would occupy but that was not enough to assure local civilians that the booster portion of the two-stage SM missile would never fall in or near a populated area. In one Aegis Ashore site there were civilian concerns about living too close to the AESA radar Aegis uses to detect and track incoming missiles. Once the Japanese media and local politicians get hold of issues like this, they stay active until the “threat” goes away. North Korean and Chinese missiles are seen as less of a threat. In Poland and Romania, Russia is always seen as the primary threat and the side effects of using Aegis are not an issue.
Japan might still reconsider but it is more likely that the Aegis Ashore funds will be used to upgrade two existing Japanese destroyers to provide these ships with Aegis ABM capabilities. This is not as effective as Aegis Ashore which, as a land base, is cheaper to maintain and always available to defend against North Korean or Chinese ballistic missiles. Ships have crews and ships spend only about a third of their time at sea.
North Korea remains the primary threat to Japan. North Korea's unwillingness to get rid of its ballistic missile and nuclear weapons programs persists. As a result, Japan is still moving ahead to expand its ballistic missile defenses. Most of these will still be based on the Aegis system, which is normally installed on large (8,000 tons and up) warships. Japan has five of these Aegis anti-missile system destroyers with another due to enter service in 2021.
The Maya class destroyers are improved versions of the earlier Atago class destroyers. The Mayas also borrow much from the first four Japanese Aegis-ABM ships, the 9,500-ton Kongos, which were built during the 1990s and modeled on the American Burke class Aegis destroyers. The Kongos have 90 VLS (Vertical Launch System) cells for anti-aircraft/missile missiles as well as ASROC anti-submarine rockets (that carry an anti-submarine torpedo to, in effect, extend the range of the torpedo by 22 kilometers). Japanese Burke type destroyers also carry a five-inch gun and eight Japanese designed anti-ship missiles (similar to the American Harpoon). The Maya class has 96 VLS cells (as do Atagos) as well as more advanced electronics that enable the Mayas to link with the U.S. Navy CEC (Cooperative Engagement Capability) that allows real-time sharing of sensor and other data in real-time between other CEC equipped ships and even shore-based systems like Aegis Ashore.
The two land-based Aegis Ashore anti-missile systems were not expected to be in service until 2024. At that point, Japan would have eight Aegis anti-missile systems and could have two more Aegis anti-missile destroyers by 2024 by upgrading the Aegis systems on two of the older destroyers. That upgrade is more likely now that Aegis Ashore has been canceled. It appears that North Korea will continue to be a threat and how much more of a ballistic missile threat China becomes is still considered less of a problem. China has a long history of threatening but not acting. North Korea has demonstrated an ability to attack without warning and did so in 2010. North Korea has always been less cooperative than China although the Chinese are still a threat.
What prompted the original Aegis Ashore order was the Japanese decision, in 2017, that it did not need the more expensive THAAD anti-missile system when it realized that two land-based Aegis systems on the main island could do the same job at less cost. That plus the Aegis equipped destroyers armed with the SM-3A anti-missile missile would enable those two land-based Aegis systems to protect all three of the home islands.
In addition, Japan has 24 Patriot anti-aircraft missile batteries that can also fire the PAC-3 anti-missile missile. The PAC-3 has one drawback; it only has an effective range of 30 kilometers against incoming missiles. The Aegis SM-3 anti-missile missile has a range of from 700 kilometers (older Block 1) to more than three times that for the later Block II models. This is why two Aegis land-based systems can protect most of Japan (the main island). The Patriot PAC-3 provides local defense for key targets (the capital and major military bases).
The first (Romanian) Aegis Ashore system appears to be as reliable as the original ship-based systems. This was expected because the East European Aegis Ashore system had never been to sea. In early 2014 the only land-based Aegis system in existence (in New Jersey) was taken apart, packed into sixty 60 18.2-meter (40 foot) shipping containers and sent to Romania where it was put back together and in 2015 was an operational anti-missile system by early 2016. After that two more ground-based Aegis systems were ordered; one in Poland and one in Hawaii (for testing and development). All three, including new Aegis components for two of them and needed missiles (24 per location) and launching hardware for all of them came out costing $767 million each. Then came the Japanese Aegis Ashore order, which were initially estimated to cost over two billion dollars for each system. Defense projects have always been more expensive in Japan because of local laws (no weapons exports) and customs (creating the maximum number of jobs with government projects).
The U.S. has long sought to put anti-missile systems in Eastern Europe to protect against ballistic missile attacks from Iran. Russia has opposed this and sees it as a subterfuge to weaken the effect of Russian ballistic missiles attacking European targets. Most Europeans don’t know what to make of that, but East European countries (like Romania and Poland) that spent 1945-89 as involuntary Russian vassal (or “satellite”) states, do see a need for protection from Russian missiles and Russian aggression and domination in general. Romanians and Poles considered Russian anger over Aegis Ashore as a benefit, not a problem.
It is different in East Asia where Japanese atrocities during World War II are still remembered. Japan, in turn, considers itself a victim of World War II and still insists it was trying to help its neighbors. The neighbors disagree and two of them, North Korea and China, openly threaten Japan with more nuclear attacks.
Meanwhile, Aegis remains one of the most effective missile defense systems available. Aegis has achieved an 83 percent success rate during live test firings. As a result, many countries want Aegis ABM (Anti-Ballistic Missile) ships for protection from local ballistic missile threats. The Aegis system was designed to operate aboard warships. These are usually cruisers and destroyers that have been equipped with the special software that enables the Aegis radar system to detect and track incoming ballistic missiles. Currently, the U.S. Navy has about 40 ships with the Aegis anti-missile system. There are over 100 American and foreign warships equipped with Aegis, but less than half of them had the software mods and anti-missile missiles that enable them to shoot down ballistic missiles and low-orbit satellites. Converting an Aegis ship to Aegis ABM costs about $30 million, mainly for new software and a few new hardware items. This is seen as a safe investment and the U.S. expects to see most Aegis equipped ships to be upgraded to ABM versions in the 2020s.
To knock down ballistic missiles Aegis uses two similar models of the U.S. Navy Standard anti-aircraft missile, in addition to a modified version of the Aegis radar system, which can now track incoming ballistic missiles. The anti-missile missile is the RIM-161A, also known as the Standard Missile 3 (or SM-3). It has a range of over 500 kilometers and max altitude of over 160 kilometers. The Standard 3 is based on the anti-missile version of the Standard 2 (SM-2 Block IV). This SM-2 missile turned out to be effective against ballistic missile warheads that are closer to their target, as is its replacement, the SM-6. One test saw a SM-2 Block IV missile destroy a warhead that was only 19 kilometers up. An SM-3 missile can destroy a warhead that is more than 200 kilometers up. But the SM-3 is only good for anti-missile work, while the SM-2 Block IV and SM-6 can be used against both ballistic missiles and aircraft. The SM-2 Block IV also costs less than half what a SM-3 costs. SM-3 is not being replaced but instead is constantly upgraded.
The SM-3 has four stages. The first two boost the interceptor out of the atmosphere. The third stage fires twice to boost the interceptor farther beyond the earth's atmosphere. Prior to each motor firing, it takes a GPS reading to correct course for approaching the target. The fourth stage is the nine kg (20 pound) LEAP kill vehicle, which uses infrared sensors to close on the target and ram it.