The world’s deepest drill is about to get taller—tall enough to dig into Earth’s mantle. Already, the Chikyu research vessel is capable of fetching samples at depths of 23,000 feet below the seabed, two to four times that of any other drill. In 2007, off the coast of Japan, it became the first mission to study subduction zones, the area between tectonic plates that is the birthplace of many earthquakes. Over the next three years, scientists will tack on at least an extra mile of drill and attempt the most ambitious mission ever: piercing the Earth’s mantle. There, scientists expect to find the same conditions as those in the early Earth—and perhaps the same life-forms that thrived then.

How to Reach the Mantle
1. Get in Position Using GPS and transponders on the ocean floor, the ship’s positioning system measures the forces acting on the craft, such as wind, wave and current direction and speed. Six computer-controlled propellers will keep the ship from drifting more than 15 feet in any direction.

2. Assemble Drill To break through the first layer of crust, the crew deploys a steel pipe with an 11-inch-wide drill bit at the bottom. The crew attaches new lengths of pipe one by one from the top until the “drill string” is long enough to hit the seafloor.

3. Start Drilling As the drill bit burrows through sediment and rock, a hose in the drill pipes in a synthetic mud to keep the drill cool and the borehole open under the crushing pressures found at those depths.