Japan to mull joining US 'satellite constellation' initiative to counter missile threats

TOKYO -- The Japanese government will consider joining the United States' "satellite constellation" initiative -- aimed at accurately observing missile movements by deploying a number of low-orbit satellites equipped with smart sensors -- through the production and launch of some of the satellites used in the system.

As part of the move, the government will begin full consideration in fiscal 2021 on ways to cooperate in an initiative to counter new types of missiles owned by China, Russia and North Korea that are difficult to intercept with existing missile defense systems. Japan will also advance development of infrared ray sensors that can detect and track missiles across an extensive area and with high sensitivity, with an eye on mounting them on satellites.

The missile defense system that Japan has heretofore adopted from the U.S., including Aegis missile interceptors, envisages ballistic missiles that fly in a parabolic arc before hitting the targets. However, China and Russia have developed hypersonic glide weapons that can follow irregular trajectories. North Korea also possesses new missiles that can follow irregular trajectories at a low altitude. Both types of weapons could penetrate existing missile defense systems.

The U.S. satellite constellation initiative is aimed at monitoring missiles, enemy movements both on the ground and in the air, and space debris by using a cluster of more than 1,000 small artificial satellites. In order to work as a missile defense system, however, it is also necessary to improve the capabilities of interceptor missiles.

Under Japan's Basic Plan on Space Development and Use, which was approved by the Cabinet in June 2020, the government included a policy to "take necessary measures" by looking into collaboration with the U.S. satellite constellation system. In the initial budget draft for fiscal 2021 green-lighted by the Cabinet in December, the government set aside 170 million yen (about $1.63 million) for launching surveys and research on subjects including optimal altitudes to detect and track hypersonic glide weapons with the satellite constellation system. The government also appropriated 1.2 billion yen (about $11.5 million) for the technological development of high-sensitive, small and lightweight infrared ray sensors, which Japan excels at producing.

The satellite constellation system is expected to cost a total of over 1 trillion yen (about $9.6 billion), making it impossible for Japan alone to develop the scheme. "A plan for Japan to launch several dozen satellites and seek information-sharing from the U.S. is achievable," noted an individual close to the government. There are also many points that remain uncertain, such as how to secure technical accuracy and the cost-effectiveness of maintaining and managing the satellite constellation system. Therefore, the government is also looking at providing cooperation in spheres other than satellite launches, such as technical assistance.

Currently, the Japanese Maritime Self-Defense Force and the U.S. Navy mutually share information acquired through their respective vessel radars. The two countries also share imagery information captured by Japanese and U.S. satellites.

The U.S. plans to first launch 20 satellites by 2022 and then boost the number to 250 by 2025. It ultimately aims to deploy more than 1,000 satellites for the detection and tracking of missiles, reconnaissance and monitoring of the ground, and getting a grasp of space debris. While conventional sophisticated early warning satellites weigh 1 metric ton each and orbit at an altitude of 36,000 kilometers, the low-cost satellites to be employed in the constellation project will be just around several hundred kilograms per unit and be put into orbit at an altitude of 300 to 1,000 kilometers.

Meanwhile, China and Russia have been developing "killer satellites" that are capable of attacking other nations' satellites. By injecting a large number of small satellites under the constellation initiative, it will be possible to make up for some of the satellites in case they are destroyed by killer satellites. The initiative is also aimed at enhancing "survivability" to maintain systems in emergencies.

In recent years, the U.S. arms race with China and Russia in space has been escalating. As of February 2020, there were 128 U.S. military satellites in space, while China had 109, Russia 106, India 21 and Japan 14. Behind Japan's move to consider collaborating with the U.S. in the satellite constellation initiative lies a sense of crisis that Japan could seriously fall behind in the development of missile interceptor capabilities.

(Japanese original by Shu Hatakeyama, Political News Department)