China's self-developed Haiqin, a 6,000-meter deep-sea remotely operated vehicle (ROV), has successfully completed a deep-sea voyage in the South China Sea. The deep-sea electric ROV system, which was designed and built by Shanghai Jiao Tong University, reached a depth of 4,140 meters during the sea trial early on August 23. For the first time ever, Haiqin worked alongside another deep-sea unmanned submersible, Haidou-1.