TOKYO (Reuters, Bloomberg) - Japan is worried the United States has so far declined to arm it with a powerful new radar, arguing the decision makes the US missile defence system it plans to install much less capable of countering a growing North Korean threat, three sources said.
Japan wants to have a land-based version of the Aegis ballistic missile defence (BMD) system operational by 2023 as a new layer of defence to help counter North Korea's missile advances.
Yet, without the new powerful radar, known as Spy-6, Japan will have to field the system with existing radar technology that has less range than a new generation of BMD interceptor missiles, the sources who have knowledge of the discussion told Reuters.
That could mean that while the interceptor has enough range to strike a missile lofted high into space, the targeting radar may not be able to detect the threat until it is much closer.
Japanese officials have witnessed a demonstration of Spy-6 technology, which boosts the range of BMD radars dozens of times, but efforts to secure the equipment from their ally have come to naught.
"So far all we have got to do is smell the eel," said one of the officials, referring to a savoury fried eel dish popular in Japan.
The military threat to Japan deepened on Tuesday when Pyongyang fired an intermediate range ballistic missile (IRBM) over Japan's northern Hokkaido island. Japanese Prime Minister Shinzo Abe slammed the action as "reckless" and"unprecedented."
Japan's Defence Ministry and the Pentagon did not immediately respond to requests for comment.
Japan already has a two-phase ballistic-missile defense system, consisting of land-based PAC-3 interceptors and Aegis-equipped ships carrying SM-3 interceptors. Deployment of the U.S.'s Terminal High Altitude Area Defense missile shield appears off the table for the time being.
Japan's Defence Ministry will this week seek a 2.5 per cent increase in its budget for the 2018 financial year, including an allocation for the Aegis Ashore missile defense system, local media reported. It will also set aside funds to upgrade its automatic alert control system because North Korea is increasingly firing missiles on a lofted trajectory, the reports said.
Washington's reluctance to share the Sky-6 radar may make Tokyo feel more vulnerable to North Korean attack and blunt US efforts to assure its Japan about its commitment to defend its East Asian ally to as tensions in the region intensify.
The new US Ambassador to Japan, William Hagerty, dubbed their security partnership as the "greatest on earth" in his first meeting with Abe on Aug 18.
The US' top general, Joint Chiefs Chairman General Joseph Dunford described that alliance as "ironclad" in talks with the Chief of Staff of Japan's Self Defence Forces, Admiral Katsutoshi Kawano the same day.
Still, a pledge to let Japan have Spy-6 has not been forthcoming. Japan has not yet placed an order for Aegis Ashore, but has informally asked Washington to let it have the new radar technology.
"There is no guarantee that Japan is going to get it," said another of the sources. The US Navy supports giving Japan the new radar, the source said, but may be thwarted by reluctance from the Missile Defence Agency, which is responsible for developing BMD technology.
Officials there are wary to release advanced technology, even to a close ally, before the United States has fielded the technology. The United States' first Spy-6 equipped Aegis warship is not slated to begin operations before 2022, one of the sources said.
Tokyo will need permission to use Spy-6 well ahead of that roll out date to give the maker, Raytheon Co and Aegis system integrator Lockheed Martin Corp time to build and test the system.
Any decision to hold back Spy-6 could therefore add significantly to Japan's already rising bill for missile defence by forcing it to pay to upgrade or replace Aegis Ashore systems after deployment.
Tokyo plans to build two Aegis Ashore batteries, costing around US$700 million each without missiles, the sources said. That would mean its southwestern Okinawa island chain would likely be protected by one of Japan's existing BMD warships.
The Aegis system's new SM-3 Block IIA defensive missiles, designed to hit warheads Pyongyang may try to fire over its missile shield, can fly more than 2,000 km - about twice the distance of the current SM-3 missiles.
The interceptor missiles will cost around US$30 million each, the sources added.