Photo/IllutrationDefense Minister Tomomi Inada during her inspection of the THAAD system developed by the U.S. military (Provided by U.S. military)

  • Photo/Illustraion
  • Photo/Illustraion

GUAM, United States--North Korean missiles raining down on Tokyo and other cities is a scenario that Japanese defense officials are now grappling with in light of a spike in tests by the reclusive state.

That is why Defense Minister Tomomi Inada visited Andersen Air Force Base here Jan. 13 for a briefing on the state-of-the-art Terminal High Altitude Area Defense system (THAAD) developed by the U.S. military.

Japan currently relies on a two-pronged approach for missile defense, but is considering adding a third element because of the rapid advances in missile technology by North Korea.

After her 40-minute tour, during which U.S. military officials explained the functions of the THAAD, Inada told reporters, "With the threat from North Korea's nuclear missiles entering a new stage, I was able to personally view what could become a new asset for Japan's missile defense."

Japan's current missile defense involves a two-tiered system.

Outside of the atmosphere, SM-3 interceptor rockets launched by Aegis vessels would target ballistic missiles, while surface-to-air PAC-3 missiles would be aimed at the ballistic missiles once they re-enter the atmosphere.

Based on the Medium-term Defense Program for the period from fiscal 2014 until fiscal 2018, the number of Aegis destroyers capable of carrying SM-3 rockets will double from the current four. Improvements will also be made on the SM-3 and PAC-3 missiles to expand the range over which they can shoot down ballistic missiles.

In 2016, North Korea fired more than 20 ballistic missiles into the Sea of Japan. Five types were tested, including a submarine-launched missile. That technology caught Japanese defense officials off-guard, said a high-ranking source, citing assessments that North Korea had not yet reached that level of sophisticated technology.

Those developments led to calls within the ministry to push for the introduction of the THAAD system because it is capable of intercepting missiles moving at far higher trajectories and even outer space.

"If a missile fell on Japan, it would cause irreparable damage," said a ministry official. "We have to fill in any 'holes' by moving to a three-tier approach."

A major hurdle for deploying the THAAD is cost. Putting the system into play would require hundreds of billions of yen, which may be beyond what the Finance Ministry would sanction given the nation's tight fiscal crunch.

"It would be impossible to respond if North Korea launched dozens of missiles simultaneously," said a former defense minister. "There would be no end in sight if we started strengthening our ballistic missile defense."

Another factor in Japan's thinking is the reaction from its neighbors if Tokyo embarks on this course.

The U.S. military's decision in 2016 to deploy the THAAD in South Korea promoted a harsh reaction from China and Russia. Beijing and Moscow cited concerns about the highly advanced radar used in the THAAD to monitor the movements of their own military forces.

When Russian President Vladimir Putin met with Prime Minister Shinzo Abe in December, he raised the issue of Japan's aims for ballistic missile defense.

However, after her THAAD inspection, Inada told reporters, "We should think about what would be most appropriate for protecting Japan."