Famed oceanographer Robert Ballard discovered the Titanic, the Bismarck, the USS Yorktown and John F. Kennedy's PT-109. 
 
 On Tuesday, he added another accomplishment to his list of documenting the world's greatest shipwrecks: the first images in more than six decades of the USS Independence, an iconic World War II aircraft carrier scuttled in 1951 off the California coast, half a mile under the sea. 
 
 In a 20-hour-long expedition, Ballard's team, working with officials from the Navy and NOAA -- the National Oceanic and Atmospheric Administration -- revealed breathtaking images of the lost carrier's flight deck, a Hellcat fighter plane, anti-aircraft guns, hatches, ladders and even the letters of the ship's name still visible on the hull, all submerged 30 miles west of Half Moon Bay. Thousands of viewers in more than 30 countries watched the discoveries live over the Internet. 
 
 "What's so wonderful about the wrecks in deeper water, like this ship, the Titanic and the Bismarck, is that they are in amazing states of preservation," Ballard said Tuesday, still at sea. 
 
 "There's very little change from when the Navy scuttled it," he said. "The deep sea is the largest museum on Earth." 
 
 Ballard, a retired Navy officer, and his organization, the Ocean Exploration Trust, based in Connecticut, plan to build a detailed 3-D digital image of the Independence from the thousands of photographs they took with two unmanned submersibles on Monday and Tuesday. 
 
 "It was really nice to read the name on the side," he joked. "You think, 'Good, I found the right ship'." 
 
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 For hours as the images streamed in at www.nautiluslive.org, the adventure riveted viewers who were discovering the fate of the ship, not seen in 65 years, at the same moments as the 31 researchers aboard the Nautilus, Ballard's ship. 
 
 Classrooms of school children emailed questions that the researchers answered in a running commentary, as huge white sponges covered the Independence decks, and deep sea sole and orange thornyhead fish swam by. Large fishing nets could be seen draped across the ship's bow and stern. 
 
 "We're pleased and surprised," said James Delgado, director of maritime heritage for NOAA, and lead scientist on the mission. "Independence is in much better condition than I had expected. It looks as it did in the 1946 photographs. It is a frozen moment in time." 
 
 Delgado said the discovery of a Grumman Hellcat fighter plane was among the most significant findings. 
 
 "It's damaged, but the star, the insignia, is still there on the wing and the 50-caliber guns are still in place," he said. 
 
 'Hellcat' fighter plane found in the wreckage (Ocean Exploration Trust) 
 
 The Independence, a light aircraft carrier that is 623 feet long, saw combat at Wake Island, Okinawa, and Leyte Gulf from 1943 to 1945, and was present a year later at the U.S. atomic tests at Bikini Atoll in the South Pacific. There, as part of nuclear tests, it was placed roughly 500 yards from two nuclear blasts so Naval officials could study their fleet's vulnerability to atomic weapons. While the Independence sustained major damage in the atomic blasts, it did not sink. 
 
 Afterward, the Navy towed the vessel back to Hunter's Point Naval Shipyard in San Francisco. Then to dispose of it, Naval officials towed it out to sea, placed two torpedoes in the ship, and detonated them, sinking the ship on Jan. 26, 1951. 
 
 The ship was all but lost until 1990 when the U.S. Geological Survey found it while mapping the seafloor. Sonar scans taken by NOAA last year provided more detail. But until now, there were no photos or video of the Independence in its final resting place. 
 
 When the ship was sunk, Navy records show, it carried an unknown number of 50-gallon barrels that contained low-level nuclear waste such as gloves, tools and boots. The barrels were filled with concrete and put in a former engine room space that was sealed. 
 
 Delgado said that Tuesday's expedition found no trace of the barrels. 
 
 Kai Vetter, a professor of nuclear engineering at UC Berkeley, said Monday that the ship and its contents pose virtually no risk to ocean wildlife or the public. The reason, he said, is that the half-life of radioactive material that the steel of the ship was exposed to is seven years, meaning it degrades by half in that time period, and 70 years has passed, leaving far less than 1 percent of the original radioactivity. 
 
 Nevertheless, a scientist from Vetter's lab was on board the expedition, and the two submersibles took samples of sediments and small creatures from the ship, such as sponges, for testing. 
 
 Ballard said there are as many as 3 million shipwrecks at the bottom of the world's oceans. Ships in shallower water are covered with sediment that washes down from rivers, he said. Because sunlight can reach them, plants grow and cover them, breaking them down faster than the ships, like the Independence, lost in the icy, pitch-black waters of the deep oceans. 
 
 With every expedition, said Ballard, 74, he takes great care never to set submersibles on the ship or to remove any artifacts, particularly if people died when the vessel sank, which was not the case with the Independence. 
 
 "I left everything on the Titanic and the Bismarck," he said. "Taking things off would be like bringing a shovel to Gettysburg." 
 
 Paul Rogers covers resources and environmental issues. Contact him at 408-920-5045. Follow him at Twitter.com/PaulRogersSJMN ||||| HALF MOON BAY -- In a ghostly reminder of the Bay Area's nuclear heritage, scientists announced Thursday they have captured the first clear images of a radioactivity-polluted World War II aircraft carrier that rests on the ocean floor 30 miles off the coast of Half Moon Bay. 
 
 The USS Independence saw combat at Wake Island and other decisive battles against Japan in 1944 and 1945 and was later blasted with radiation in two South Pacific nuclear tests. The Navy deliberately sank the contaminated ship in 1951 south of the Farallon Islands. 
 
 The U.S.S. Independence, a WWII-era aircraft carrier, has been discovered beneath 2,600 feet of water off the coast of the Farallon Islands. This image from NOAA depicts the Independence as it appeared during its wartime service and a sonar image of the ship at rest at the bottom of the Pacific Ocean, upright and mostly intact. (Courtesy NOAA) 
 
 The rediscovery of the USS Independence offers a fascinating glimpse into American military history and raises old questions about the safety of the Farallon Islands Radioactive Waste Dump -- a vast region overlapping what is now a marine sanctuary where the federal government dumped nearly 48,000 barrels of low-level radioactive waste between 1946 and 1970. 
 
 The expedition to locate and survey the Independence was led by the National Oceanic and Atmospheric Administration, with help from the Navy and Boeing, which mapped the wreck last month using a robotic underwater vehicle equipped with cutting-edge sonar capable of producing three-dimensional images. 
 
 The images, which show the hull of the ship remains remarkably intact, suggest the Independence lived up to its nickname, "The Mighty I." 
 
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 The 623-foot-long ship took a remarkable degree of punishment over its 10-year career, said NOAA official James Delgado, chief scientist of the Independence mission. After World War II, the Independence was engulfed by a fireball and heavily damaged during the 1946 nuclear weapons tests at Bikini Atoll, transformed into a floating nuclear decontamination lab while stationed at Hunters Point Naval Shipyard in San Francisco, then finally towed out to sea laden with untold barrels of radioactive waste and scuttled with two torpedo warheads. 
 
 The Independence was sunk on Jan. 26, 1951, and came to rest 2,600 feet below the ocean surface. 
 
 The Navy withheld the location of the wreck for decades, but the U.S. Geological Survey found its likely resting place while mapping the sea floor in 1990. In 2004, a NOAA ship captured a distant image of what looked like a giant caterpillar stretched on the bottom of the ocean, said Delgado, who has led a two-year mission to find and study historic shipwrecks in and around the Gulf of the Farallones National Marine Sanctuary. 
 
 "This ship is an evocative artifact of the dawn of the atomic age, when we began to learn the nature of the genie we'd uncorked from the bottle," said Delgado. "It speaks to the 'Greatest Generation' -- people's fathers, grandfathers, uncles and brothers who served on these ships, who flew off those decks and what they did to turn the tide in the Pacific war." 
 
 Delgado said he doesn't know how many drums of radioactive material are buried within the ship -- perhaps a few hundred. But he is doubtful that they pose any health or environmental risk. The barrels were filled with concrete and sealed in the ship's engine and boiler rooms, which were protected by thick walls of steel, Delgado said. 
 
 The submarine that mapped the Independence got within 200 feet of the wreck, he said. Scientists tested the vehicle and the water on its instruments for radioactive isotopes and found only normal background radiation levels, he said. 
 
 But word of the Independence survey stirred up lingering concerns about the nuclear waste near the Farallon Islands, an area teeming with wildlife. Retired judge and state legislator Quentin Kopp, who many years ago demanded research into the Navy's disposal of radioactive material off Northern California before 1970, said Thursday that the question of whether the waste posed a risk to humans and wildlife was never resolved. 
 
 "If I were an elected legislator, state or federal, I would be pounding the table," Kopp said. 
 
 Kai Vetter, a UC Berkeley nuclear engineering professor who assisted the survey, said the ocean acts as a natural buffer against radiation. And the contaminated sites are small enough that they wouldn't work their way into the broader food chain, he added. 
 
 "The risk here to have a public health impact is extremely small," Vetter said. 
 
 Vetter said he hopes to obtain samples of the hull of the Independence in the next year to analyze the effects of radiation and other forces on the metal. Delgado said, however, there are no plans to further examine the wreck at this time. 
 
 The Gulf of the Farallones sanctuary is a haven for wildlife, from white sharks to elephant seals and whales, despite its history as a dumping ground. 
 
 Richard Charter, a senior fellow at the Ocean Foundation, was involved in the creation of the sanctuary back in 1981. He said the radioactive waste is a relic of a dark age before the enviornmental movement took hold. 
 
 "It's just one of those things that humans rather stupidly did in the past that we can't retroactively fix," he said. 
 
 Contact Aaron Kinney at 650-348-4357. Follow him at Twitter.com/kinneytimes. ||||| Scientists have surveyed a World War II-era aircraft carrier scuttled off the coast of San Francisco in 1951, advancing our understanding of how thoroughly we can explore the ocean floor while providing new knowledge about how ships fare after decades under water. 
 
 The 3-D sonar survey of the USS Independence was part of a two-year project by the National Oceanic and Atmospheric Administration to find and document hundreds of wrecks in the Gulf of the Farallones and learn more about the area’s rich maritime and biological history. 
 
 As ships go, the Independence is worthy of a biopic. After the Japanese attack on Pearl Harbor, the US scrambled to rebuild its war machinery, an effort that included a new class of midsize aircraft carriers. The first of them was the Independence, launched in August 1942. It fought in the Pacific and survived a torpedo attack. Among its sailors and aviators was Butch O’Hare, the first naval recipient of the Medal of Honor during World War II. 
 
 After the war, the Independence was part of a huge flotilla the Navy dispatched to Bikini Atoll in 1946 to understand the effects of nuclear radiation on ships. After being blasted twice, it was off to Hunters Point Naval Shipyard in San Francisco, where the Navy studied radioactive decontamination. 
 
 In January of 1951, the brass decided the Independence was no longer useful, too expensive to scrap, and might sink at any time. It was towed to the Farallon Islands, 30 miles off the California coast, loaded with two torpedo warheads the Navy was testing (talk about using the whole buffalo), and scuttled. 
 
 Today it rests at a depth of 2,600 feet. A survey of the area in 2009 revealed something that might have been the Independence, but no one was quite sure. “It looked like a caterpillar,” says James Delgado, director of maritime heritage at NOAA. 
 
 But recent developments in sonar offer the clearest view yet of what’s beneath the sea. A 3-D sonar called Echoscope, made by UK-based Coda Octopus and carried by the Echo Ranger underwater autonomous vehicle, brought things into much sharper focus. Last month’s survey offers a surprisingly detailed look at the ship, revealing the hangar deck and elevator hatches, along with what may be an airplane. 
 
 This mission was largely designed to test the Echo Ranger, an 18-foot long, 10,000-pound, vaguely whale-shaped UAV designed by Boeing (which paid for the survey). The Independence, being the biggest and deepest known shipwreck in the area, was “the absolutely ideal target” for seeing what the Ranger could do. The big issue with sonar is stability; readings taken from a bumpy ride translate to bad data. The Ranger was up to the task: “It’s a big yellow box with a tail and a propeller that proved to be a very stable platform,” Delgado says. 
 
 NOAA also wanted to see if the Echo Ranger could be deployed from a relatively small ship. Using the 67-foot catamaran Fulmar instead of a larger and more expensive research vessel saved NOAA tens of thousands of dollars a day, Delgado says, and it worked just fine. 
 
 Lastly, the researchers wanted to get a better idea of how well the Echo Ranger would survey the wreck. It’s autonomous—the team gives it general instructions but doesn’t control its exact movements—and performed quite well. “Mowing the lawn,” it went back and forth 150 feet above the wreck, fully surveying the entire site. 
 
 The sonar readings don’t reveal everything. Learning what kind of flora and fauna may have colonized the wreck, for example, would require sending down a camera (something that isn’t planned). But NOAA did verify the ship is in good shape after six decades in salt water. The hull and flight deck are largely intact, and the ship is upright, listing to starboard. 
 
 The ability to answer such questions is about more than idle curiosity. There are ships scattered on the ocean floor all around the world, many of them loaded with fuel and oil. NOAA maintains a database of known wrecks, in part to keep an eye out for leaking contaminants that can do environmental harm. A greater understanding of how these ships deteriorate leaves NOAA and other agencies better equipped to prevent an ecological disaster. “The big interesting thing,” Delgado says, “is what happens to these things on the bottom over time.”
– The USS Independence has remained submerged a half-mile deep off the coast of California for 65 years, out of human sight since it was purposely relegated to the bottom of the ocean by the US Navy in 1951, reportedly with a bunch of 50-gallon barrels containing radioactive waste, per the Mercury News. This week, however, thousands of viewers watched as the first photos other than sonar scans of the 623-foot aircraft carrier were shown live online, courtesy of the same ocean explorer who discovered the Titanic, among other famous shipwrecks—and those pics show the Independence is in remarkably good shape in its watery grave. "There's very little change from when the Navy scuttled it," Robert Ballard says of his team's documentation, in conjunction with the Navy and the NOAA, adding the Titanic was similarly well-kept. "The deep sea is the largest museum on Earth." Viewers saw such wonders as the Independence's sponge-covered flight deck, a Grumman Hellcat fighter plane, and even the ship's name imprinted on its hull, all at the same time as researchers on the Nautilus exploration vessel, who sent out two remote-controlled submersibles Monday and Tuesday to capture the pictures about 30 miles west of Half Moon Bay. What the deep-sea dive didn't find: any evidence of the atomic waste rumored to have been sunk with the ship, per USA Today, though a UC Berkeley nuclear engineering expert tells the Mercury News any danger posed by such waste would've long since dissipated. The 74-year-old Ballard says he treated his newest subject with the same respect he does all his shipwrecks, leaving artifacts intact. "Taking things off would be like bringing a shovel to Gettysburg," he says. (Sonar images of the Independence were first seen last year.)