A manned deep-sea submersible is being developed by Japanese researchers to get a closer look at the seafloor. It's aptly called the Shinkai 12000 as it will be capable of diving to depths of up to 12,000 meters (7.5 miles), deeper than the deepest known point at the Challenger Deep within the Mariana Trench at 10,911 meters (6.8 miles) below the Pacific Ocean's surface.

Japan currently has the Shinkai 6500. This submersible was launched over a quarter of a century ago and has the capacity to dive up to 6,500 meters (4 miles) in depth. The Shinkai 6500 has done good work exploring the seafloor for the Japanese, but the Japan Agency for Marine-Earth Science and Technology has been feeling the pressure to develop a new submersible to go beyond what the Shinkai 6500 has accomplished.

According to JAMSTEC, the Shinkai 12000 should be ready for use in the latter parts of the 2020s. Designed to explore the seafloor for organisms and natural resources, the submersible will be big enough to fit a crew of six. It will also have enough energy and storage capacity for supplies to last for a two-day mission and will be fitted with space for resting and bathroom facilities.

While the Shinkai 6500 was made out of titanium alloy and had small port holes for researchers to peer through and observe where they are, the Shinkai 12000 will be fitted with a glass sphere. Toughened at 5 to 10 centimeters thick, the glass sphere will drastically improve visibility to increase observable areas.

With glass susceptible to breaking due to pressure at such deep depths, shattering even with the smallest scratch, JAMSTEC will have to work on ensuring the submersible's durability. At 10,000 meters (6.2 miles) under the sea, water pressure can reach up to 1 ton for every square centimeter.

At the moment, China is leading the pack with a submersible capable of reaching depths of up to 7,000 meters (4.3 miles). France and Russia are not far behind with their own submersibles diving up to 6,000 meters (3.7 miles) underwater.

The Shinkai 6500 went on its first mission in 1991 to study the seafloor's geology and topography, researching as well deep-sea organisms living in the Pacific Ocean, Indian Ocean and the Atlantic Ocean. Of course, the submersible has taken numerous trips around Japan's seas. As of 2012, the Shinkai 6500 has gone on 1,300 dives in the name of sea exploration.