China's latest 4,500-meter-level submersible starts first exploration

The Qianlong No. 3 unmanned submersible started its first exploration in the South China Sea on April 20, 2018. The Chinese-made autonomous underwater vehicle (AUV) is expected to dive to a depth of 3900 meters. The submersible has a length of 3.5 meters, a height of 1.5 meters and a weight of 1.5 tons. This photo shows the preparation work done before the mission. [Photo: Xinhua]