Submersible returns to service after upgrade

The Jiaolong, China's first manned deep-sea research submersible, has reentered service after a major technical upgrade, completing dives in a recent hardware-testing mission in Chinese territorial waters, according to the Ministry of Natural Resources.

In a news release, the ministry said on Wednesday that during the mission, which took place from Feb 27 to Tuesday, the submersible set a record for its operational frequency — it conducted 14 dives within a 10-day period, including four days in which the vessel performed two dives each day.

The operations were supported by the Deep Sea 1, the country's first dedicated mother ship for submersibles, it added.