ABOARD KEXUE -- The Chinese-developed underwater robot Tansuo had collaborative underwater operations with the unmanned submersible Faxian in the South China Sea on Wednesday.

It is the first time that the two types of submersible have performed simultaneous underwater explorations.

The robot started to make a 10-hour dive at 6:40 am to obtain camera images and collect real-time data in a 0.36-square-km area of the South China Sea.

The unmanned submersible, which carried a raman spectrometer, dived at 9:30 am to measure marine physical and chemical parameters in the area.

The Chinese research vessel Kexue, carrying both the Tansuo and Faxian, started its maritime scientific expedition on July 10 in the South China Sea.

Previously, China's research vessel had to monitor an underwater robot's operations and could not simultaneously conduct other explorations after the underwater vehicle dived into the sea.