Following a successful test dive in the Pacific, Chinese scientists say they're on course to complete one of the world's deepest ever dives next year.
The Jiaolong sub is 8.2 meters long and weighs 22 tons. It reached a depth of 5,057 meters early this morning, spending over six hours underwater. It carried a crew of three.
"At a depth of 5,000 metres, the Jiaolong withstood great pressure amounting to 5,000 tonnes per square metre," the head of the diving operation, Wang Fei, told state news agency Xinhua.
At that depth, he said, the sub could reach over 70 percent of the world's sea bed. It's an interesting way of looking at things, given that last year Jiaolong was used to plant a Chinese flag on the seabed of the hotly-disputed South China Sea, which is rich in oil and gas.
And the Jiaolong team aims to go deeper. Next year, it's planning a manned 7,000 meter dive. Back in 1960, the US Navy sent a manned capsule to the bottom of the Mariana Trench, 11,500 meters down, but it remained there for only 20 minutes.
Jiaolong, by contrast, can 'move back and forth easily under the sea', according to its designers. They add that it has a 'state-of-the-art' communication system and high-definition video equipment on board, which were tested during this morning's dive.
A Japanese sub, Shinkai, reached a depth of 6,500 meters in 1989.