Pressure Dive

After two months of testing DEEPSEA CHALLENGER on shallower dives, Cameron was poised above the deepest place on Earth. No one had imagined diving in seas this rough. A key safety system had failed. But it was now, or never.

This story appears in the June 2013 issue of National Geographic magazine.

Storm season was rolling in, and time was running out. Rough seas kept delaying James Cameron’s dive to Challenger Deep, lowest spot of the Mariana Trench, at nearly seven miles below the surface. When the swells subsided just a little, the ship’s captain gave the go-ahead. Cameron climbed into the capsule and watched a crew member seal and lock the 400-pound hatch. In this exclusive account, he describes the intensity and wonder of his white-knuckle ride to the bottom.

05:15, MARCH 26, 2012 11° 22' N, 142° 35' E
Predawn in a pitch-black sea. My sub DEEPSEA CHALLENGER heaves and lurches as huge Pacific swells roll above me. We’ve all been up since midnight, starting our predive checks after a couple of restless hours of sleep, and the whole team is running on adrenaline. These are the roughest conditions I’ve dived in so far on the expedition. Through my external cameras I can see the two divers just outside my tiny cockpit getting whipped around like tetherballs as they struggle to rig the sub for descent.

The pilot’s chamber is a 43-inch-diameter steel ball, and I’m packed into it like a walnut in its shell, my knees pushed up in a hunched sitting position, my head pressed down by the curve of the hull. I’ll be locked in this position for the next eight hours. My bare feet rest on the 400-pound steel hatch, locked shut from the outside. I’m literally bolted in. People always ask me if I get claustrophobic in the sub. To me it just feels snug and comforting. My visual field is filled by four video screens, three showing views from the external cameras, one a touch screen instrument panel.

The sub, painted electric green, is hanging upright in the swells like a vertical torpedo aimed at the center of the Earth. I tilt my 3-D camera, out on the end of its six-foot boom, to look up the face of the sub. The divers are getting into position to release the buoyant lift bag attached to the sub, holding it at the surface.

I’ve had years to contemplate this moment, and I won’t say there hasn’t been dread in the past few weeks, thinking about all the things that could go wrong. But right now I feel surprisingly calm. I am wrapped in the sub, a part of it and it a part of me, an extension of my ideas and dreams. As co-designer, I know its every function and foible intimately. After weeks of pilot training, my hand goes to a specific control or switch without thinking. There’s no apprehension at this point, only determination to do what we came out here for, and childlike excitement for what’s ahead.

Let’s do this. I take a breath and key the mike. “OK, ready to initiate descent. And release, release, release!”

The lead diver yanks a lanyard, freeing the lift bag. The sub drops like a stone, and in seconds the divers become toy figures far above on the churning surface. They dwindle and fade, leaving only darkness. A glance at the readouts shows that I’m dropping at almost 500 feet per minute. After a lifetime of dreaming, seven years developing the sub, grueling months of construction, and the stress and emotion of the voyage here, I’m finally on my way to Challenger Deep, the deepest spot in the world’s oceans.

05:50, DEPTH 12,500 FEET, SPEED 3.5 KNOTS
I pass the depth of Titanic in only 35 minutes, going four times the speed of the Russian Mir submersibles we used in 1995 to film that famous wreck for the movie. At that time Titanic seemed to me to exist at the most extreme depth imaginable, and going there was as exotic as traveling to the moon. Now I give a jaunty wave as I pass that depth as if I’m going down my driveway past the mailbox. Fifteen minutes later I pass 15,617 feet, the depth of the battleship Bismarck. While I was exploring that wreck in 2002, the bulb of a floodlight imploded with the force of a grenade going off just outside our Mir’s hull. That was my first experience with a deepwater implosion. If DEEPSEA CHALLENGER’s hull fails, I won’t feel a thing. It’ll be a CUT TO BLACK. But that won’t happen. We spent three years designing, forging, and machining this little steel sphere. I trust our engineering and the engineers who put it all together.

The external temperature is reading 35°F, down from 85° at the surface. The pilot’s sphere is cooling rapidly, its inside now covered with big drops of condensation. My bare feet, pressed against the steel of the hatch, are freezing. In the confined space it takes several minutes to put on wool socks and waterproof booties. I pull on a watch cap to protect my head from the cold wet steel pressing down on me, and yeah, OK, to look more like an explorer. In the darkness outside, the only indications of movement are particles of plankton racing upward through the sub’s lights, as if I were in a car driving in a blizzard.

06:33, 23,200 FEET, 2.8 KNOTS
I’ve just passed the maximum operating depth of the deepest diving manned submersible in the world, the Chinese Jiaolong. Minutes ago I passed the maximum depths of the Russian Mirs, the French Nautile, and the Japanese Shinkai 6500. I’m going deeper than any other piloted sub in existence can go. And all those other subs were the products of government-funded programs. Our little green torpedo was built privately, in a commercial space sandwiched between a plumbing supply wholesaler and a plywood shop in the suburbs of Sydney, Australia. Our team members, most of whom had never worked on a sub before, came from Canada, China, the United States, Australia, and France. This was a passion project for dreamers from all over the world, who believed they could do the impossible. Today we’ll see if we can.

06:46, 27,000 FEET, 2.5 KNOTS
I’ve just gone below the depth of my previous solo record dive in the New Britain Trench, off Papua New Guinea, three weeks ago. It seems incredible that I still have 9,000 feet to go. Time seems to stretch. I’ve gone through every item on my descent checklist, and I have nothing to do during this long, quiet fall through limbo but think and watch the depth numbers tick higher. The occasional hiss of the oxygen solenoid is the only sound. I look at my feet on the hatch and think about the massive force pushing in against it. If the sub springs a leak, the water will drill in like a laser, cutting right through anything in its path—myself included. I think about how that would feel. Would it hurt? Does the question have any meaning if you’re alive for only another second or two?

07:43, 35,600 FEET, 0.5 KNOTS
Another hour has passed, with the sub slowing during the final 9,000 feet. I’ve dropped some shot ballast, steel ball bearings released by an electromagnet to trim the sub’s buoyancy. I’m almost “neutral,” neither heavy nor light, descending very slowly on thrust alone. The altimeter indicates the bottom is 150 feet below. The cameras are all rolling, the lights aimed straight down. I’m gripping the thruster controls, white-knuckled, peering at the blank screens.

One hundred feet ... ninety ... eighty ... I should be seeing something. Seventy ... sixty ... Finally, I see a ghostly glow reflecting from the bottom. It looks as plain as an eggshell, with no detail, no scale reference to judge distance. I give a tiny braking burst with the vertical thrusters. Five seconds later the faintest downwash hits the seafloor, and the nothingness below me ripples like a silken veil.

I’m not sure yet if there really is a solid surface. Taking a hand briefly off the thruster controls, I aim the spotlight outward across the landscape. The water is gin-clear. I can see far into the distance: nothing. The bottom is utterly uniform, devoid of any character but the absence of character, of dimension and direction. I’ve seen seafloors in more than 80 deep-ocean dives. Nothing like this. Nothing.

07:46, 35,756 FEET, ZERO KNOTS
I nudge the sub downward, closing the gap to the bottom. On the boom camera I see the foot of the vehicle sink in about four inches before it stops. I’m down. The descent has taken two and a half hours. A cloud of the finest silt I’ve ever seen rises up in silken tendrils like cigarette smoke, hanging almost motionless. Then, a voice from seven miles above me: “DEEPSEA CHALLENGER, this is surface. Comms check.” The voice is faint but eerily clear. Our calculations suggested there wouldn’t be any voice comms at all this far down.

I glance at the depth gauge and key the mike. “Surface, this is DEEPSEA CHALLENGER. I am on the bottom. Depth is 35,756 feet ... life support’s good, everything looks good.” Only now does it occur to me that I might have prepared something more memorable, like “One small step for man.” At least I’ve got my watch cap.

Long seconds tick by as my message races up from the bottom of the world at the speed of sound and the answer comes back down. “Copy that.” The ex-Navy man on comms is even more matter-of-fact than I am. Military training. But I can visualize them all grinning and clapping up there on the ship. I know my wife, Suzy, will be glued to the telemetry screen, deeply relieved. I feel a surge of pride in the team, in their accomplishment. Most of the guys who built the sub are up there in that control room, scarcely believing yet what they’ve achieved. The sub is a tangible manifestation of their imagination, their knowledge, and their will. Infused with their collective spirit. In a sense they are all down here, with me.

Thirty-five thousand seven hundred fifty-six feet. What the hell, I’ll round it off to 36,000 feet at cocktail parties. The next voice I hear is completely unexpected. “Godspeed, Baby,” Suzy says, sending radar love down to the most remote place on Earth. Hearing her voice, my two worlds collide in a strange but beautiful way. Suzy has been by my side throughout the expedition, hiding her apprehension and backing me 100 percent. I know it’s been nerve-racking for her.

Time to get to work. We’ve planned for just five hours on the bottom, and there is a lot to do. I turn the sub, using the cameras to peer around at the world I’ve arrived in. The bottom is flat and featureless in all directions. An alien limbo. I power up the hydraulics, open the external door to the science compartment, then deploy the manipulator arm to take my first sediment core sample. If everything goes to hell in ten minutes, at least I’ll be coming back with some mud for the scientists.

It was never enough just to build a sub that could set the world’s depth record. It was important to me that it be a science platform as well. There’s no point in exploring the least understood frontier on our planet and not being able to record data and take samples.

Core sample safe on board, I take a moment to shoot a close-up of the Rolex Deepsea watch for the Swiss firm that has partnered with us on the expedition. The watch, strapped to the manipulator arm, is still ticking, despite 16,300 pounds per square inch of pressure. In 1960, as part of a U.S. Navy project, Lt. Don Walsh and Jacques Piccard dived in the massive bathyscaph Trieste to the same depth, the only other humans to ever do so. They also brought a specially built Rolex, and it too withstood the pressure just fine.

But not everything is working so well. Moments after taking an image of the watch, I see constellations of yellow oil globules floating up across my viewport. The hydraulic system is leaking. In minutes I lose all function in the arm, and the science door as well. With no more ability to take samples but my cameras still working, I set off to continue exploring.

09:10, 35,752 FEET, 0.5 KNOTS
With short bursts of the thrusters, I’m driving north across a plain of ponded sediment, as the geologists call it. The surface is like new-fallen snow on an endless parking lot. I haven’t seen anything alive on the bottom, and only occasional amphipods floating past, tiny as snowflakes. Soon I should be encountering the “wall” of the trench, which I know from our multibeam sonar maps is not really a wall, but rather a gently rising slope. I hope I’ll find exposed rock outcroppings that might harbor life.

All my viewing so far has been through the high-definition cameras. Remembering a promise I made to myself before the dive, I decide to land the sub. There is no way I’m coming down here to the deepest place in the ocean without seeing it with my own eyes. It takes me several minutes to move the equipment out of my way and contort myself into a position where I can look directly out the window. I spend a few minutes taking in the stillness of this alien place, so far from all human experience. Human eyes have been down this deep only once before. But Walsh and Piccard dived 23 miles west of here, in another part of the Challenger Deep now called the Vitiaz Deep. No one has ever seen this place before.

All other deep seafloor that I’ve ever visited, even as deep as 27,000 feet in the New Britain Trench, was crisscrossed with the tracks of worms, sea cucumbers, and other animals. Here there is literally no sign of life. The surface is undisturbed, and has been for who knows how long. I know it’s not truly sterile—we’ll almost surely discover new species of microbes living in that sediment sample I took earlier. But I have the inescapable feeling that I’ve dived beyond the limits of life itself. And with that comes an awe, a sense of the great privilege of being here, of bearing witness to a primordial world.

Some scientists on our team think life may indeed have originated in these black hadal depths, some four billion years ago, powered by the slow, steady chemical energy generated as one tectonic plate was dragged inexorably under another, releasing trapped fluids. This darkling plain has been here for countless eons, existing whether we witness it or not. I am humbled by the vastness of all we don’t know, both down here and out in the darkness of space. I feel how tiny a candle I’ve brought in these brief minutes and how enormous the task remains to explore our world.

10:25, 35,686 FEET, 0.5 KNOTS
I’ve found the north slope and am working up along its gently undulating ridges. I’m about a mile north of my landing site. So far no rock outcroppings. In my travel across the flat trench floor I’d found and photographed two possible signs of life: one a gelatinous blob smaller than a child’s fist sitting on the bottom, the other a dark scar five feet long that might have been the home of a subterranean worm of some kind. Both were enigmatic and unlike anything I’d seen in years of diving. I took good HD images, and I’ll let the scientists puzzle over them. A couple of my batteries are dangerously low, my compass is glitching, and the sonar has died completely. Plus, I’ve lost two of the three starboard thrusters, so the sub is sluggish and hard to control. The extreme pressure is taking its toll. I press on, knowing that time is running out but hoping to get to the kind of steeper cliffs I saw in the New Britain Trench, which harbored a completely different community of animals from those on the trench floor.

Abruptly, I feel the sub yaw to the right, and I check my thruster status display. The one remaining starboard thruster has failed. Now I can only turn in circles. I can’t take samples, and I can’t explore beyond this point, so there is no productive reason to stay. I’ve been on the bottom less than three hours, far less than my planned stay of five. Reluctantly, I call the surface and tell the team I’m preparing to ascend.

The moment when you throw the switch that drops the ascent weights always gives you pause. If the weights don’t drop, you’re not coming home. Period. I spent years designing the weight-release mechanism, and the engineers who built and tested it did a thorough job making it the most reliable system on the sub. But as you reach for that switch, you always wonder. I don’t milk it out, thinking about it. I just throw the switch.

Click. I hear the familiar shtoonk as the two 536-pound weights slide out of their tracks and plummet to the seafloor. The sub lurches, and the bottom immediately drops away into its abiding darkness. As the speed builds up, trapped sediment churns violently out of the sub’s science bay, like the ice falling off the cryogenic tanks during a Saturn V launch. I feel the sub buck and rock as it fires upward. I’m going over six knots, the fastest the sub has ever gone, and I’ll be on the surface in less than an hour and a half. I imagine the pressure coming off the sub, like a great python that was unable to crush it slowly giving up its grip. A feeling of relief washes over me as the numbers get progressively lower. I’m on my way back to the world of sunlight and air, and Suzy’s sweet kiss.

DEEPSEA CHALLENGE is a joint scientific expedition by James Cameron, the National Geographic Society, and Rolex. Learn more at