HAIKOU - China's science ship Tansuo-1 loaded with the manned submersible Shenhai Yongshi (Deep Sea Warrior) returned to its home harbor in Sanya, South China's Hainan province, on Sunday, after finishing its first expedition in the Indian Ocean.

The manned submersible can reach a depth of 4,500 meters. The 121-day expedition trip organized by the Chinese Academy of Sciences began Nov. 10, 2018. Scientists from 10 Chinese and foreign research institutes were invited to join the deep-sea research trip.

The ship traveled 17,000 nautical miles on the expedition during which scientists surveyed five deep-sea hydrothermal areas and collected a trove of samples for ecological environment research.

The submersible Shenhai Yongshi conducted 62 dives. Scientists succeeded in retrieving it in a variety of conditions including stormy waves and during the night.

The development of the submersible took eight years and involved over 90 Chinese organizations and companies. It conducted deep-sea testing missions in 2017 and 2018.