Photo taken on Nov. 25, 2014 shows Xiangyanghong 09, the carrier of China's manned submersible Jiaolong, in Jiangyin City, east China's Jiangsu Province. Jiaolong started a scientific research voyage to the southwest Indian Ocean on Tuesday. (Xinhua/Zhang Xudong)

JIANGYIN, Jiangsu, Nov. 25 (Xinhua) -- China's deep-diving manned submersible Jiaolong, inside its carrier Xiangyanghong-9, left Jiangyin Port in east China's coastal Jiangsu Province on Tuesday.

This will be the sub's maiden scientific expedition to the southwest Indian Ocean.

During the four-month mission, it will descend into the depths 20 times to focus on the research of polymetallic sulfides, biological diversity, hydrothermal microbes and genetic resources, said the mission's chief commander and director of the National Deep Sea Center, Yu Hongjun.

This will be the furthest and longest voyage for Jiaolong in terms of distance and time.

The ambitious ocean exploration program began in 2002.

Named after a mythical dragon, Jiaolong has reached a top depth of 7,062 meters in the Pacific's Mariana Trench in June 2012.