The darkness is matched by the intense pressure. Four miles down, it amounts to nearly five tons per square inch. That is too much even for Alvin, the most famous of the world’s tiny submersibles, which can take a pilot and two scientists down to a maximum depth of 2.8 miles.
But a new submersible is being built here, and even the process of construction seems a rebuke to the darkness. The work lighted up a cavernous factory with fireworks on a recent visit. Hot reds and oranges burst into showers of spark and flame as blistering metal began to yield to the demands of the submersible’s design.
“Amazing,” Tom Furman, a senior engineer at Ladish Forging, said after a big press bore down on an 11-foot disk of hot metal, making the delicate manipulation look as easy as rearranging a gargantuan pat of butter.
The new vehicle is to replace Alvin, which was the first submersible to illuminate the rusting hulk of the Titanic and the first to carry scientists down to discover the bizarre ecosystems of tube worms and other strange creatures that thrive in icy darkness.
The United States used to have several submersibles — tiny submarines that dive extraordinarily deep. Alvin is the only one left, and after more than four decades of probing the sea’s depths it is to be retired. Its replacement, costing some $50 million, is to go deeper, move faster, stay down longer, cut the dark better, carry more scientific gear and maybe — just maybe — open a new era of exploration.
Its architects at the Woods Hole Oceanographic Institution on Cape Cod describe it as “the most capable deep-sea research vehicle in the world.”
Alvin can transport a pilot and two scientists down 2.8 miles, providing access to 62 percent of the dark seabed. The new vehicle is expected to descend more than four miles, opening 99 percent of the ocean floor to inquiry. But the greater depth means that the vehicle’s personnel sphere and its many other systems will face added tons of crushing pressure.
“Technologically, it’s quite challenging,” Robert S. Detrick Jr., a senior scientist and vice president for marine facilities and operations at Woods Hole, said of forging the new personnel sphere. “It’s also something that hasn’t been done for a long time in the United States.”
To better resist the sea’s pressure, the wall of the new personnel sphere is to be nearly three inches thick, up from Alvin’s two inches. Deep explorers always use spheres to make crew compartments because that geometry best resists the crushing force.
“We have confidence it can be done,” Dr. Detrick said in January of the sphere’s forging. “But we don’t have a lot of margin for error. If the first forging is bad, it would be quite expensive to redo it.”
That air of uncertainty hung over teams of engineers and oceanographers who gathered in late June at Ladish in the Milwaukee suburb of Cudahy.
The objective of the metalworking company was to transform two giant disks of titanium — stronger and lighter than steel, and perfect for withstanding the vast pressures of the deep — into twin hemispheres. If forged successfully, the cuplike hemispheres would be welded together to form the beginnings of the personnel sphere, initiating the vehicle’s birth.
Ladish, its plant nearly a mile long, is a maze of ovens and workshops, forges and presses — giant versions of the hammers that blacksmiths use to manipulate hot metal. Employees wear hardhats, safety goggles and, when conditions warrant, ear plugs.
“No hot loads,” a sign warned as a group of visitors moved deep inside the factory. “Hardhats required beyond this point,” read another.
A star of the site is hydraulic press No. 154, a behemoth that rises some five stories high. For decades, its operators have quietly advanced the nation’s exploration agenda by turning ingots of hot steel into rocket casings.
Now, the operators have turned their attention to inner space. In late June, after much preparation and computer modeling, sirens wailed and they drove the ram of their giant press down onto blistering hot titanium, the glowing disk half a foot thick and 11 feet wide. Smoke and flame shot upward.
“You have to move fast,” Douglas B. Roberts, a manager at Ladish, said amid the fireworks. “That big a piece cools off quickly.”
In seconds, the big press transformed the radiant disk into an enormous cup. The next day, it made another. Even after an hour of cooling, the big cup still radiated waves of heat.
“It went fantastic,” Mr. Furman, the chief engineer for design engineering at Ladish, told a group of officials and visitors.
The overall process of forging, welding, machining, heat treating, cutting view ports, annealing, finishing and testing the new personnel sphere is to be done at several companies around the country and is expected to take about two years. The completed crew cabin, seven feet across, will be a foot wider than Alvin’s.
Oceanographers say the new sphere will help open the sea’s depths. Its volume is 18 percent larger than Alvin’s, allowing twice as much room inside for racks of scientific equipment and a bit more space for passengers.
Alvin has three thick windows through which the pilot and scientists can peer out at the undersea world. The new vehicle will have five, increasing the field of view and the chance for discovery and careful observation.
“It’s going to be incredible,” said Cindy L. Van Dover, a professor of marine biology at Duke University who has spent hundreds of hours diving in Alvin. She noted that scientists would have two windows that look forward. By contrast, Alvin’s scientific viewports look off to the side, with only the pilot getting the central view.
“Forward is cool,” she said, calling it rich in drama, lights and action.
For instance, Dr. Van Dover said the forward view could best reveal a towering hot spring surrounded by exotic forms of life.
“In Alvin, a scientist can’t see that,” she said. “Also, you want to see where your samples are being taken and how they’re being taken. You want to be able to direct the pilot.”
Dr. Detrick of Woods Hole called forging the new personnel sphere one of three big technical hurdles. The others, he said, are making the vehicle’s foam and its banks of batteries. The foam must be hard enough to resist crushing pressure yet buoyant enough to counteract the vehicle’s great weight. And the batteries must be unusually sturdy and powerful.
If successful, the new batteries will allow the vehicle to stay on the bottom for up to eight hours, compared with six for Alvin. Improvements in the vehicle’s propulsion system, including more powerful thrusters, will let it move faster. And the vehicle’s new lights and cameras will better pierce the darkness.
Still, like its predecessor, the new vehicle, over all, is to be no larger than a small truck.
Dr. Van Dover said one of the big payoffs would be the submersible’s ability to dive deep.
“Depth is a big deal,” she said. “It’s hard to wax lyrical on the subject because we don’t know what’s there. So we can’t guarantee a discovery. Yet we know that every time we extend our ability to go somewhere, we discover new things about how the planet works, about how life on the planet is adapted.”
The new vehicle is also seen as building national pride and international goodwill, because foreign scientists at times join the dives.
Submersibles can also foster geopolitical aims. A year ago, a team of Russians trekked to the North Pole and plunged through the ice pack in a submersible to the dark ocean floor. There, they planted Russia’s flag and, upon surfacing, declared that the feat had strengthened Moscow’s claims to nearly half the Arctic seabed.
Just when the replacement Alvin will join the world’s small fleet of submersibles has become uncertain.
Like many federal projects, it faces cost overruns and financing troubles. When first proposed in 2004, the anticipated bill ran to $21.6 million. But delays set in and the price of materials, planning and contracting ran higher than expected. Officials say titanium alone has seen a fivefold price increase.
The National Science Foundation, the federal agency that sponsors the project, has too many competing needs to meet the new estimated cost of about $50 million. So officials at Woods Hole came up with a phased approach that promises to lower the immediate expense.
In an Aug. 8 letter, Susan K. Avery, the president of Woods Hole, outlined the plan to Deborah Kelley, a University of Washington oceanographer and chairwoman of the Deep Submergence Science Committee, a team of researchers that advises the government on abyssal exploration.
The new personnel sphere, she said, might first be fitted onto Alvin’s body, giving the old submersible a life extension and a capability boost. Alvin would also get new batteries, new electronics, better lights, cameras and video systems. But the hybrid would be limited to Alvin’s depth of 2.8 miles.
The second phase, Dr. Avery said, would build a new submersible body that would let the replacement vehicle dive to the full intended depth of four miles.
How soon? The original schedule of 2004 foresaw the replacement vehicle as ready in 2008. Early this year, amid growing uncertainty, the keepers of the schedule put the date at 2010. Now, the soonest the upgraded Alvin might hit the water is estimated to be 2011. And the full replacement, according to Woods Hole officials, might not materialize until 2015.
“Phase 2 is about finding additional resources,” Dr. Detrick said. “It’s a matter of money.”
Officials talk about a $25 million shortfall and hopes that a private donor might materialize who could close the gap and ensure the speedy debut of the new submersible and its program of deep inquiry.
For explorers like Dr. Van Dover, that day cannot arrive soon enough. “We can apply 40 years of experience and build it right,” she said. “That’s the beauty.”
By WILLIAM J. BROAD
Published: August 25, 2008
No comments:
Post a Comment