Submarine

Aquanauts take one giant step for China

PUBLISHED : Sunday, 31 July, 2011, 12:00am
UPDATED : Sunday, 31 July, 2011, 12:00am

The second dive to 5,000 metres will begin at 1.30am, July 26. China Central Television will have a live broadcast.

Please don't watch.

Ye Cong , captain of deep-ocean submersible the Sea Dragon, sent this e-mail to his parents and wife from a 30-year-old ship pitching and rolling in a storm on the Pacific Ocean. He always writes them an e-mail before a mission.

At 5,000 metres, the pressure on his submersible would amount to the weight of a 100,000-tonne aircraft carrier. There was no escape capsule and no rescue team. The main battery would last only a few hours. It had leaked during the first dive.

Yet down he went.

The bad weather meant the Sea Dragon launched a few hours behind schedule on Tuesday - but it reached a depth of 5,034 metres.

Together with two crew members, the captain completed a few careful manoeuvres using seven electric-powered propellers, scooped up some sediment samples with a robotic arm and took a few photographs of deep-sea creatures.

Between the monitors, joysticks and buttons there was little room left for the three men. Stretching their legs was out of the question. A light bulb was kept dim to save power and the electronic equipment added to the heat and stuffiness.

In an earlier interview with Xinhua, Ye said his job was as challenging as an astronaut's. But the aquanauts arguably have a tougher time. There is no floating free from gravity, little glamour and no wonder at seeing the earth from space. Instead, their unique view of the world is glimpsed via a camera with the help of a searchlight and viewed on a computer screen.

And yet Ye, a former engineering student from Wuhan , has said he loves his job because of the freedom it gives him. Once he leaves the mother ship, he is allowed to make all the decisions by himself.

'I feel like the general of an expedition in the old days,' he told the Guangming Daily last year. 'I can ignore orders from the emperor.'

In the pursuit of oil, minerals and prestige, the government mobilised tens of thousands of scientists and engineers to build the world's deepest manned research submersible. The Sea Dragon, built to be able to manoeuvre freely at depths of 7,000 metres, represents China's latest advances in physics, chemistry, artificial intelligence, communication technology and materials.

But some scientists have questioned whether it is necessary to send humans to hazardous depths, when more advanced countries like the United States and Japan use robots. They argue that looking through a tiny glass window several inches thick onto a dark and muddy ocean floor with zero visibility does not lend itself to scientific discoveries.

Xu Qinan , chief designer of the Sea Dragon, told Xinhua: 'Of course, many of the advanced technologies were absorbed and adapted from submersibles developed by other countries. Some technology, such as high-definition filming and data transmission, still depends on imported products.'

With China the fifth country to make deep-ocean manned submersibles, he said China's technology was now more mature than that used in some projects overseas. 'The rule of scientific development determines the equipment of latecomers to be more advanced,' he said.

The super-tough hull of the Sea Dragon uses a titanium alloy. It was made and imported from Russia, said Zhao Junhai, the hull designer and a senior engineer with China Ship Scientific Research Centre in Wuxi, Jiangsu province.

The project began in 2002. Zhao's team worked out the fluid dynamics to create the shape of the ship and then drew up specifications for hull materials. No factories on the mainland could produce anything close to what they needed.

'The strength and quality of a hull determines the maximum operational depth of Sea Dragon,' Zhao said. 'Our military submarines only need to dive a few hundred metres. To operate at 7,000 metres we need something very thin, very light but almost indestructible.'

When the hull arrived from Russia, an X-ray scan produced a jaw-dropping result. No scanner on the mainland could penetrate the material, according to Jiangsu-based newspaper Modern News Express. The technology used by the Russians was totally alien to the Chinese.

But mainland researchers learned fast. Cui Weicheng, deputy designer, told Scientific Chinese magazine last year that they had fully absorbed all the foreign technology used in the making of the Sea Dragon, including the hull materials.

'We have learned all the core technology and we have been gradually replacing imported equipment on board with domestic products. Even if other countries cut off parts supply, we will be able to build another Sea Dragon to replace it,' Cui was quoted by the magazine as saying.

He Bingshou, associate professor with the Oceanic University of China in Qingdao, Shandong, said he could not understand the need to risk sending people into the depths of the Pacific. A marine mining expert, he said modern technology has enabled machines to do most, if not all, of the dirty work on the ocean floor.

For instance, researchers can pin down the possible location of a mineral field or natural gas reserve in a big, bright laboratory, a cup of tea in hand, by looking at high-definition and three-dimensional structures generated by seismic surveys.

'If we need live video feeds for a special location, we can always send a robot. Most robots can be fitted with a high-definition digital camera or a sophisticated mechanical arm. They can do everything from surveillance to sample collection,' He said.

'Nobody needs to risk their lives.'

Shi Xuefa, chief scientist of China Ocean Mineral Resources Research and Development Association, disagrees. Many scientists had an urge to see with their own eyes the subject of their study.

Black smokers in the deep ocean floor, for example, provided significant clues to the formation of mineral deposits. These chimney-like hydrothermal vents emit sulphur which blends with metallic elements such as copper.

Many mainland scientists believe that if they had a chance to observe these vents closely, they could get a better idea how to find and exploit ocean minerals, Shi said, adding: 'It is well worth the risk.'

Alvin, the world's most famous submersible - owned by the US Navy but operated by scientific institutes - has revolutionised our understanding of marine creatures and even the concept of life itself since it was launched in 1964. Not only has it discovered breathtaking geological phenomena, including the black smokers, but also many forms of life at extreme environments where nobody believed that they could exist. It is manned and has done thousands of dives to depths of up to 4,500 metres.

A record set by the US Navy back in 1960 for the deepest dive by a manned submersible still stands, at 11,000 metres.

The Sea Dragon has not made any discoveries yet. The test dives will come to an end next year, assuming the submersible reaches its maximum operational depth of 7,000 metres on schedule.

At that point, Chinese scientists will enter territories never visited by a manned vessel.