The Shinkai 6500, one of only 10 manned submersibles in the world, has a lifespan of approximately 5 years.

Japan has many “ultra-deep seas,” a treasure trove of rare metals and other resources, in the seas around Japan, but…

There are 22 ultra-deep-sea trenches in the world that are deeper than 7,000 m. Six of these trenches are in Japan’s exclusive economic zone. Six of them are in Japan’s exclusive economic zone. It is believed that a variety of mineral resources, including rare metals, lie in these ultra-deep seas. The potential for Japan to become a resource-rich country is right around the corner. So why not focus on building submarines?

Because mineral resource extraction can be done by unmanned vehicles.

Certainly, surveys of marine mineral resources are being conducted, and new mineral deposits have been discovered in the waters of Okinawa, Izu, and Ogasawara.

There is always a debate about whether unmanned vehicles can be used instead of manned submersibles. For example, if you want to collect mud from the seafloor and find organisms in it, you can do it with either unmanned or manned submersibles. However, with drones, the location of where you drop them off will depend on the chance of where you drop them off.

On the other hand, with a manned aircraft, a human can see and move around.

With a manned aircraft, on the other hand, a human can see and move around. “With a human, you can see the whole area, near and far, so you can pick a good spot and move on, but with an unmanned aircraft, you have to focus the camera to see. Also, we can move and observe the deep sea with our five senses, feeling the flow and turbidity of the water. The study of nature begins with seeing it with your own eyes.”

Without discovering something previously unknown and knowing how it functions and what it is doing, science cannot progress. That is important for the study of the earth, especially the global environment, according to Dr. Kitasato.

Dr. Kitazato himself has dived to 8,000 meters aboard a foreign manned submersible.

The trenches in Japan’s Exclusive Economic Zone are all unique, with slightly different crustal deformations. When landslides occur due to large-scale crustal deformation such as the Great East Japan Earthquake, you can see dynamic ecosystem transitions, such as new organisms taking up residence there. You will never get tired of seeing them.”

Currently, we get donations and foreign private research vessels to take us there.

Now that it is technically impossible to build a manned submersible in Japan, Dr. Kitasato envisions creating an organization that will serve as the core of ultra-deep-sea research and a platform to promote research.

A manned submersible is extremely expensive, but an unmanned exploration robot lander can be built for just over 10 million yen. To take it to the ocean, we need to charter a ship, train personnel, etc. If we organize a one-month voyage once every two years, it will cost roughly 300 to 500 million yen over five years.

However, this is much cheaper than the tens of billions of yen spent on rocket launches. With that, we can get closer to the mysteries of the ultra-deep ocean around Japan.

Dr. Kitasato hopes to continue his research by collecting donations from people who agree with his plans to investigate the ultra-deep sea.

“I think we can also take the opportunity to have foreign private research vessels take us out to investigate the deep sea around Japan, like we did in August and September of ’22 when we investigated the Ogasawara Trench and other areas of the deep sea around Japan. With high aspirations, I would like to fulfill my dream.

There are probably still craftsmen in Japan who possess outstanding skills. If such people get together, they may be able to build a submarine. I believe it is my job from now on to create such a system.

When the Shinkai 6500 reaches its end of life in five years, its pilots will lose their jobs. Dr. Kitasato says that by conducting research together with foreign commercial research vessels, the pilots may be able to keep their jobs.

The first submersible was built in Japan in 1929. It was called Nishimura-type submersible and could dive down to 200 meters. After the war, Hokkaido University built the Kuroshio in 1949, followed by the Shinkai 2000 and the Shinkai 6500, and there is a long history of manned submersibles being built.

In order to keep that history alive, I believe we must start this project immediately.

We wish Dr. Kitasato the best of luck, but we wonder if the Japanese government will simply back away from the development of manned submersibles.

Dr. Hiroshi Kitasato is currently a visiting professor at the Department of Marine Environmental Science, Tokyo University of Marine Science and Technology, after serving as the Director of the Marine and Extreme Environment Biosphere Area of the Japan Agency for Marine-Earth Science and Technology. He is also a Senior Research Fellow at the Danish Institute for Ultra Deep Sea Research. He specializes in geology, earth life science, deep-sea biology, and marine micropaleontology. He was awarded the Yokoyama Prize of the Palaeontological Society of Japan in 2010. He is the author of Deep Sea, Another Universe: The Birthplace of Life as Seen by the Shinkai 6500.