On March 26, 2012, National Geographic Explorer-in-Residence James Cameron succeeded in tackling his biggest challenge ever: a solo journey to Challenger Deep, the deepest known point in the ocean. Challenger Deep is 10.99 kilometers (6.83 miles) below the surface and found at the southern end of the Mariana Trench off the coast of Guam.

In order to make the journey, Cameron and his team utilized revolutionary engineering and cutting-edge technology to develop the single-seat submersible that Cameron piloted solo to the depths of Challenger Deep. Named DEEPSEA CHALLENGER, the sub is 7.9 meters (26 feet) long and unlike anything ever built.

Cameron's team carefully studied the physical geography of the South Pacific when planning the expedition. Unpredictable weather conditions above the Mariana Trench, like 9 meter (30 foot) swells and winds that regularly exceed 25 knots, meant that conducting practice dives at the Challenger Deep site would be exceedingly dangerous. Instead, the expedition team charted a course that used the bathymetry (the topography of the ocean floor) of the Pacific Ocean to safely conduct practice operations en route to the Mariana Trench.

The team began in the protected shallows of Australia's Jarvis Bay, where Cameron could safely make short test dives. The expedition then followed the ocean floor's sloping bathymetry north. The progressively deeper sea floor allowed Cameron to make longer dives without the risks of operating in the open ocean. Two months later, after thorough testing and many practice dives, the team arrived at the Mariana Trench where Cameron successfully dove to the world's deepest point.

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  1. Why would a natural harbor like Jarvis Bay be safer for Cameron's crew than the open ocean above the Mariana Trench?

    • Answer

      In the open ocean large swells and strong winds can make for dangerous conditions, even for large ships like the Mermaid Sapphire. Harbors like Jarvis Bay have land barriers that protect the water from swells and wind, making them much safer for delicate operations like testing the DEEPSEA CHALLENGER sub.

  2. What types of tests did Cameron and his team need to conduct before attempting to dive to Challenger Deep? Why were they important?

    • Answer

      The extreme depth of Challenger Deep, nearly 11 kilometers (nearly 7 miles) under the surface, meant that any malfunction during Cameron’s dive could be life threatening. The team needed to test everything about the sub to ensure no problems would occur. The physical construction was tested for watertightness, the scientific and communications equipment were tested for water usage, and hydraulic and engine design were tested for proper propulsion.

  3. Why is the area of Guam where Cameron’s crew stops to resupply nicknamed “Typhoon Alley?”

    • Answer

      The nickname comes from the frequency with which typhoons (the name for hurricanes originating in the Pacific Ocean) and earthquakes hit the area. “Typhoon Alley” includes Guam, the Philippines and Japan. During typhoon season, tropical cyclones often form in the central and western regions of the Pacific, and then track westward across the “Alley.”

  4. Why didn't Cameron's team sail directly for the Mariana Trench?

    • Answer

      Cameron and his crew needed to conduct numerous tests and practice dives before attempting to reach Challenger Deep. Unpredictable weather and ocean conditions above the trench would have made practice dives there nearly impossible. Instead, the team charted a course that incorporated stops for practice dives and tests en route to the Challenger Deep dive site.