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				Going Deep Part 1 - Into the Deep For decades, explorers have been perfecting the crafts that can brave crushing pressure on deep sea dives. Alvin is one successful submersible -- used first by the Navy, then by scientific expeditions.
		Select text to jump ahead in the clip: ALDA: Woods Hole, Massachusetts. It's one of the picturesque seaside towns that draw the tourists to Cape Cod each year. But few seaside towns have what Woods Hole has. For 70 years it's been home to the Woods Hole Oceanographic Institution, an organization that does nothing but study the world's oceans. While the tourists on Main Street are thinking about fried clams, all around them, the folks at the Institution-- or "Who-ee" as it's universally known-- have other things on their minds. Like this, for instance. It's the submarine that's going to be exploring the world's oceans for the first half of the 21st century. The new sub is to replace this one, the Alvin. Arguably the most successful deep-diving sub ever built, Alvin's still at work after 40 years-- but now it's getting hard to maintain. And no, it's not named after a chipmunk, although oceanographers think it's just as cute. It's actually named for Allyn Vine, a WHOI scientist who championed the cause of ocean exploration. ( applause ) In the summer of 1964, Alvin made its first tentative dives in the shallow waters around Woods Hole, often with Allyn Vine on board. The essential component of any deep-dive sub is the part you can't see here, the massive pressure hull that protects the crew. The first submarine ever built in America was the Turtle. Oh, really? ALDA: Bob Ballard started workingwith Alvin at WHOI in 1967. This sister ship to the Alvin has a pressure hull that's a steel ball about six feet in diameter inside, hidden in the structure. There's a single small hole in the top of the ball. BALLARD: This is the important part is the hatch... two inches thick. What keeps the water from going in here? It's actually tapered. If you look at the hatch, it's like the portholes, and pressure pushes them down. In fact, you're most vulnerable at the surface. That's the most dangerous time. You don't have the pressure seating it. All right, well, let's get down inside here. So watch your step. Right down here. Stand down on that. BALLARD: Absolutely a sardine... Oh, my God, it's tiny! ALDA: In 1869, 100 years before Alvin's launch, the French writer and ocean sailor Jules Verne published his classic story of the renegade scientist who travels the world's oceans in his fabulous submarine, Nautilus. None of Captain Nemo's technology existed at the time, of course, although in Hollywood's 1916 version, the self-contained diving suits were a genuine technical advance. The adventures of Captain Nemo and his crew were an inspiration for generations of ocean explorers, including Jacques Cousteau and Bob Ballard. While some features of the Nautilus brilliantly foreshadowed later developments, Jules Verne did skip over the challenges of water pressure. Submarines like the Nautilus, capable of accommodating large crews, developed rapidly during the Second World War. Yet water pressure limited the best of the German U-boats to a depth of about 700 feet, and today's large submarines can go no deeper than a thousand or so. It was Otis Barton, an engineer from Massachusetts, and his collaborator, William Beebe, who first solved the problem of how to reach extreme depths. The solution was to dive in a small, massive sphere. They called it a bathysphere. A spherical form offers the most effective resistance to the crushing pressures at depth. In a series of dives off Bermuda in the 1930s, they shattered the existing depth record of 525 feet, established by a diver in an armored suit. The bathysphere was simply lowered from a barge, a risky business since any fault in the cable would lead to a fatal plunge to the bottom. It was the peculiar subs called bathyscaphes, conceived by the Swiss balloonist Auguste Piccard in the 1930s, which finally reached the deepest part of the ocean, the 35,000-foot Challenger Deep off Guam. A huge tank of gasoline provided flotation, so you didn't need a suspension cable. Bathyscaphes were safer, but very unwieldy, as Bob Ballard discovered personally. BALLARD: The front of the submarine came down and I'm looking at it, and it's just the metal and everything, it's just... twisting in my eyes, like a giant... just slowly, just very slowly taking the submarine and just ripping it open. And then I see av gas coming out. ALDA: What's that? That's the flotation gasoline. We ruptured our tank. How did this turn out? Did you live? Well, here's what happened. We then... he dropped the whole... Then you could drop the whole door, and he dropped ten tons. When he saw that, I said, "Av gas..." when I yelled, "Av gas!" he dropped the doors open and we dropped ten tons. Now... we're at 20,000 feet. It's a six-hour trip home, and here's what happens. You're leaking your gasoline and you start decelerating and then you start back down. Well, they had in the sub a little calculator, you know, one of those little LED displays? ( mimics clicking, stopping suddenly ) Freezes up on a number? ( mimics clicking, stopping ) And so every few seconds, it was... and telling you your ascent rate. Well, there was enough uncertainty in the calculation that it depended upon whether you were an optimist or a pessimist. You could get whatever you wanted out of those numbers. You didn't know whether you'd make it to the top before you lost your gasoline, which gave you the buoyancy. And then you'd go negative. No one spoke. The most silent experience I've ever had, and we all looked at those numbers... For six hours? For six hours. ( mimics machine clicking ) And we were decelerating because we were losing flotation. But we had enough to get home. ALDA: Although Alvin has done some great science-- as we'll see later-- it was originally built for the U.S. Navy and operated by WHOI. Its first deep dive to 6,000 feet was to check out a secret listening array off the Bahamas. Soon after that, Alvin was brought here, off the coast of Spain, to play a starring role in a famous cold war incident. In the '60s, B-52 bombers loaded with live H-bombs were always in the air. One such patrol, returning to North Carolina, had a catastrophic collision with its aerial refueling tanker. Seven crew members died, and four H-bombs plunged to earth. Mercifully, they didn't explode, and three were recovered on land. The fourth, though, was 2,000 feet down in the Mediterranean. Alvin found the bomb after 19 dives by following a long gouge in the sea floor spotted by the WHOI crew. The gouge led to the bomb's parachute. This film has never been shown before, by the way. Alvin's remote-control arm couldn't recover the bomb, but it did help guide a secret new Navy robot to snag the parachute and haul the bomb up. There had always been doubts about whether Alvin would really turn out to be useful, but not anymore. The incident showed that people could routinely reach unprecedented ocean depths, and so could robots. This tension between manned and unmanned deep diving has continued to this day. A unique ship made from these surplus Navy pontoons was to cause a near disaster for Alvin, as well. Alvin was carried to dive sites on Lulu, then lowered into the water between the pontoons, suspended on steel cables. In 1968, this was the result. A suspension cable on Lulu had snapped, and Alvin had fallen into the sea with the three crew members inside and the hatch open. The sub sank in 60 seconds, but not before the crew scrambled or were pulled to safety. After seven months, a secret Navy camera system towed by this ship, the Mizar, found the wreck. Another deep-dive sub, the Aluminaut, was brought in. The plan was for the Mizar to dangle a nylon rope down to the Alvin. Then the Aluminaut would use its remote-control arm to hook the rope to the wreck. It took two trips over three months, but they finally did it, and Alvin was winched up 5,000 feet from the floor of the Atlantic. In our next story, we'll look at some of the important science results that Alvin went on to achieve over the next three decades. But first, take a look at the famous sandwich that came up in the Alvin, in perfect shape after a year on the bottom. It led WHOI scientists to look closely at slow decomposition at depth and then argue against the idea of deep-ocean disposal of waste. It was a great service performed by one sunken sub and one bologna sandwich.

				Going Deep Part 2 - Deep Science In 1977, Alvin scientists discovered a whole new world -- an underwater ecosystem reliant not on the sun, but on volcanic vents on the ocean floor.
		Select text to jump ahead in the clip: We're in the eastern Pacific, near the Galapagos Islands. We're going to go on a typical deep science dive into the Galapagos Rift. The Alvin's made thousands of such dives over the last three decades. TECHNICIAN: Have a good one. ( over radio ): Sealing the hatch. Hatch is secure. ALDA: But this dive, which our cameras filmed a few years ago, is in many ways the classic Alvin dive. It was here in 1977 that people for the first time gazed out from the sub at a kind of life we never knew existed. PILOT: Hatch is closed, oxygen on, C02 scrubber on, ID light on. Request permission to dive. TECHNICIAN: Roger, you're clear to dive. Depth of the target is 2,485. Clear to dive. Roger, Alvin diving. ALDA: We're going down to 8,000 feet, although the metal ball that's protecting us can safely reach 15,000. It will take us two hours to reach the bottom. My depth is 1,620, one-six-two-zero. ( repeated over speaker ): 1620, one-six-two-zero. ALDA: The acoustic radio echoes through the ocean. Everything looks normal, Jim, so far. JIM: Okay. We'll be on the bottom before long. 600 meters to go. ALDA: We're diving on a part of the ocean ridge system, an enormous undersea mountain range that snakes around the globe. In the 1960s, we realized the mountains are actually volcanoes which create the earth's crust. Then in the '70s, deep-diving subs like the Alvin began to visit the ocean ridges. PILOT: A2, this is Alvin... at the bottom. Depth is 2507, two-five-zero-seven, ambient temperature, two point zero four nine. ALDA: First, we're gliding over lava fields. Then the water begins to warm up. And we see... giant clams. They were first glimpsed in 1976, by a remote camera system from the Scripps Institution of Oceanography. The next year, in a WHOI expedition led partly by Bob Ballard, Alvin came down and found the clams, found hot water vents and found a whole new kind of life on earth. Clustered around the underwater volcanic springs-- called hydrothermal vents-- was an array of unknown life-forms, thriving in the warm currents-- tube worms, clams, mussels, crabs and fish. At first, scientists couldn't figure out how these things survive. Up above, all life depends on sunlight and photosynthesis-- but here there is no sunlight. It turned out that life here depends on kinds of bacteria that were new to science. They live on the energy of the earth itself, consuming hydrogen sulfide gas that's dissolved in the water that flows from the vents. This may be how life on earth began. The scientist on our dive, Jim Childress from UC Santa Barbara, does not always look out the window, as you might expect. Instead, he's watching a TV monitor, while the pilot, Ralph Hollis from WHOI, collects the samples Jim wants. It makes sense for professional pilots to run the sub's systems, but it can be frustrating for the scientists not to see directly what's happening. CHILDRESS: Where are you, sort of right where the tube comes out of the rocks? HOLLIS: Well, I'm about... I'm up to the yellow mark, into the fissure where the tube worms are. ALDA: How pilots and scientists can best work together on the ocean floor is going to change in Alvin's replacement. A2, Alvin, request permission to surface. Request permission to surface. CONTROLLER: Roger. ALDA: To surface, the Alvin drops a thousand pounds of steel ballast maybe right on top of a biology sampling area. Both weights away. ALDA: Later, we'll talk about plans for new working conditions, and ballast, in Alvin's replacement. The objective, though, will remain the same-- take scientists down and get them back with their amazing finds. In 1979, Alvin made another historic find, in an area called the East Pacific Rise, off Baja California. They called them black smokers-- chimneys spewing out clouds of mineral-rich water, so hot that it must have come from deep in the earth's crust. This explained why the sea is so full of minerals. BALLARD: The seawater, which is under pressure, goes right down into those cracks, goes down to the magma chamber. The magma chamber is hot-- 1,400 degrees... 1,200 to 1,400 degrees centigrade. And so it heats up the water, and then the water begins to interact with the magma chamber, and it changes its chemistry. Now, does the water turn to steam? No, it can't, because of pressure. It turns into superhot water. Superhot water, which means it stays... Liquid. Liquid, but it's really... Really hot. And it's now full of chemicals that it didn't have before. And it's those chemicals that are coming out of the black smokers that are responsible for the chemistry of the world's oceans. In fact, we now realize that the entire volume of the world's oceans is going inside the earth and out every six to eight million years. Every six to eight million years. The entire volume... All the oceans in the world, they all go down... Through this system. Under the floor of the ocean. Into the mountain range, and come up in the form of black smokers. And it takes eight or ten million years... For the whole ball game. That's a lot of water. Well, of course. And that's what's caused the chemistry of the world's oceans. And we didn't know that. ALDA: Diving in Alvin is not the only way we've discovered how the oceans and their inhabitants work, but it's been an amazingly successful way. Next we'll see how the folks at WHOI think they can make a better Alvin.

				Going Deep Part 3 - Greater Depths When Alvin retires in a few years, what will its successor be like? Scientists are designing the next generation of manned submersible.
		Select text to jump ahead in the clip: ALDA: We're back at WHOI on Cape Cod. Every three years, Alvin has to break away from whatever ocean it's exploring and return home. Then it gets torn apart and overhauled. They say there's not an original piece of the sub left. In 1973, the all-important pressure hull was replaced with a titanium version that could go twice as deep, to 15,000 feet. The white blocks are a special foam, made of microscopic glass bubbles, that can withstand the pressure of the deep ocean. It's what gets Alvin back to the surface-- you just drop some weight, and the sub floats up. That's why the Alvin is so safe-- no main ballast tanks needing pumps and valves to empty. Barrie Walden's group at WHOI is responsible for designing Alvin's replacement. He's checking out the Sea Cliff, a U.S. Navy sister ship to Alvin, retired in 1998. Sea Cliff could dive to 20,000 feet-- 5,000 deeper than Alvin-- but the basic design is the same. And inside the cramped pressure hull, the drawbacks are the same, too. WALDEN: When these submersibles were first designed, video was nowhere near as capable as it is today. So the designers purposely wished for the observers to have different views than what the pilot had, so that they wouldn't be wasting the human eyeball, essentially. So these viewports do not overlap. The observers can't see what the pilot is doing. The new Alvin is going to be different than that, in that the pilot viewport will still be in approximately the same position, but the observers' viewports will be pulled around to the front and raised a little bit, to give them the same sort of view that the pilot has. ALDA: This is the other wato explore the oceans. It's an ROV-- remotely operated vehicle. Now that video is so capable, ROVs can send high-quality pictures through a fiber-optic cable, back to the control room on the ship. It's cheaper and safer than sending people down. They can take samples remotely, too. Next will be AOVs-- autonomous vehicles that can find their own way out and back. So why build another deep submarine for people? WALDEN: Whenever I find somebody that is a champion of the other methods of doing this kind of work, the easiest thing I can do to convince them that there is a place for manned submersibles is let them make a dive. There are some benefits that you get from actually being there, looking around in person, that you just don't get from a cable-controlled vehicle or a vehicle that gives you data a week after it's recovered, kind of situation. Now, I'm not saying that we should have nothing but manned submersibles. My argument really is that we need at least one manned submersible. ALDA: In the belief that that view is correct, computer models and plywood and fiberglass are now getting together to create Alvin's replacement. This is a mock-up of the pressure hull-- although it won't be sliced in half. Bob Brown, a former Alvin pilot, heads up the design team. Here you can see the pilot's seat. Where the pilot will sit will be a movable little chair. And he would sit like this, with his viewport here. The blue around here indicates the actual size of the viewport. The simulator viewport we have is much smaller. The actual one will be bigger. We have a small pilot's desk here in the middle, and this is something that he can look at by glancing down when he's looking out the viewport. ALDA: The hull diameter is about six inches larger than Alvin's inside. Combined with touchscreen controls and miniaturized electronics, that will give a much roomier cabin. But there'll still be a few old-fashioned, clunky controls. We do have... on the switches above here, we have switches for vital systems that are necessary for getting the submersible back to the surface. ALDA: The sub will use the same tough glass foam as Alvin, but it won't be dropping steel weights to surface. Instead it will pump water out of ballast tanks. In an emergency, it will still be able to jettison all kinds of parts to get back up. The biggest change, though, is the two scientists having their own ports to look out front. All three people will be able to work cooperatively. Put your head up there. We're not going to be fighting for space, are we? ALDA: Current Alvin pilots, like Bruce Strickrott, come in regularly to try out the mock-up. The new sub will go to 21,000 feet-- 6,000 more than Alvin. To have reasonable working time on the bottom, it'll need to go down and up twice as fast. So this sub will be streamlined, and it'll almost fly up and down, at an angle. What will this feel like at 20 degrees nose down in the descent? Yeah, we'll have to, uh... Make some sort of vertical backrest or something. Well, probably a chair back here, probably not even sit on that, and he can have his chair back here for going up and something else for going down, to be determined yet. And these things can be changed to allow for angles. ALDA: The goal is, in three years, to have all this carved in stone... or rather forged in titanium. The sub will give scientists routine access to 99% of the earth's ocean floor, in a whole new style. STRICKROTT: I think it's like the difference between a Motel 6 and a Hilton. They're going to love it, are you kidding me? It's bigger, they got more viewports, they get to look out front-- they never get to look out front. They get benches to sleep on on the way up and down. How could they not like it?