The U.S. Navy on Dec. 20 recovered its "Ocean Glider Unmanned Underwater Vehicle" near the location in international waters off Subic Bay in the Philippines where it was "unlawfully seized" by a People's Liberation Army Navy (PLAN) submarine rescue ship on Dec. 15.
There's no word if China took apart the glider to copy its digital data, but this is taken as a given since the glider remained in Chinese hands for almost a week. And, of course, the Chinese have all the photos and technical data they need to make copies of the glider.
China has continued developing deep-diving underwater gliders despite a decades-old U.S. ban on exports of these vehicles to China out of concern China will put the torpedo-shaped gliders to military use.
An underwater glider is an autonomous underwater vehicle (AUV) that uses small changes in its buoyancy to convert vertical motion to horizontal, thereby propelling itself forward with very low power consumption.
Underwater gliders, which are motorless and have wings, trace an up-and-down sawtooth motion through the water. This method of propulsion allows gliders to travel farther than AUVs powered by electric motor-driven propellers.
The United States is the world leader in this technology while the U.S. Navy is one of its biggest backers.
The U.S. at the time said the seizure of the glider is arguably a violation of freedom of navigation norms.
The U.S. Navy said the USS Mustin (DDG-89), an Arleigh Burke-class guided missile destroyer, on Dec. 20 recovered Glider Unmanned Underwater Vehicle 50 nautical miles northwest of Subic Bay.
Among other details of this bizarre episode only now revealed include:
*The glider was returned to the same location by the PLAN warship that stole it: a Dalang III-class submarine rescue ship with pennant number ASR-510.
*The USS Mustin is on patrol in the United States Seventh Fleet area of operations in support of security and stability in the Indo-Asia-Pacific region.
*The glider is an unclassified vehicle that gathers military oceanographic data, including salinity, water temperature and sound speed, which are data useful in anti-submarine warfare.
*Its equipment and electronics consist of off-the shelf components worth $150,000 .
*The U.S. claims the glider is "a sovereign immune vessel" of the United States.
*China said the incident China Foreign confirms the "stable military-to-military relations" between the two countries.