Satellite Photo Shows New Activity at China’s Underground Submarine Base

Satellite imagery appears to have captured the activation of a possible damage control system at an underground submarine base for Chinese nuclear-powered submarines operating from the contested South China Sea.

A photograph supplied to Newsweek by Virgnia-based BlackSky, a real-time, space-based intelligence company, showed the unusual activity occurring at Longpo Naval Base on the afternoon of September 2, at a tunnel entrance on the island of Hainan, China’s southernmost province.

The image shows a possible Type 093A attack submarine leaving the base with signs of cavitation on the water’s surface and apparent water spray directed toward it at the tunnel entrance. Cavitation is caused by a submarine’s spinning propeller blades, which create bubbles in the water.

Experts in Chinese naval development told Newsweek that they had not seen the water spray before. The Chinese Defense Ministry did not respond to an emailed request for comment.

The conventionally armed Type 093A uses nuclear propulsion and is capable of striking ships and submarines with missiles and torpedoes. Four of them, as well as two original variants of it, the Type 093, have been built over the past 15 years, the Pentagon reported last year.

Longpo base, which has six 754-foot wharves to moor 12 submarines, is known to be the home of China’s fleet of Type 094 boats, nuclear-armed and -powered Chinese ballistic missile submarines. The underground base protects them from attacks and surveillance.

On September 3, a satellite image captured by BlackSky spotted a total of two Type 093A submarines and four Type 094 submarines docked at four wharves, including the one that was observed departing from the submarine tunnel the previous day.

A Chinese military observer, who requested anonymity due to the sensitive nature of the topic, said the water spray may be for nuclear pollution cleaning during an ABC—atomic, biological and chemical—attack on the base, which is located at the northern end of the South China Sea.

“The submarine would be cleaned of any radioactive or biochemical contaminants that might be on the surface before entering the bunker,” the observer told Newsweek. The system may have been undergoing tests when it was captured by BlackSky’s satellite.

Tom Shugart, a former U.S. Navy submarine commanding officer and an adjunct senior fellow at the Center for a New American Security, also believed the spray could be part of a nuclear, biological and chemical—or NBC—washdown system for China’s submarines.

The water spray at the Chinese submarine base might clean the vessel before it enters the tunnel, Shugart told Newsweek. Washdown systems are a countermeasure commonly found on surface warships, which use sprinklers to decontaminate hazards such as radioactive fallout or chemicals.

“Alternatively, it could be related to a venting/draining mechanism that works to support the docking facilities inside,” said Australia-based maritime security analyst Alex Luck.

There is little information on what exactly the tunnel contains. Luck told Newsweek: “Underground naval facilities remain a relatively rare feature globally, even more so for nuclear-powered vessels.” It was plausible that a dry dock was part of the infrastructure, he said.

H.I. Sutton, a maritime security analyst, wrote in 2020 that a “surprising” number of nations had built tunnels to protect their submarines and warships from attack, including China and ally North Korea—the main users—as well as NATO members Sweden and Norway.

Defense analyst Thord Are Iversen, a former Norwegian naval officer, said he was unaware of anything similar to the water spray at underground naval bases in either Norway or Sweden. “But that doesn’t mean they don’t have it,” he told Newsweek.

Besides Type 093 and Type 093A boats, China also launched two Type 093B submarines between May 2022 and January 2023, according to the Pentagon’s report. The Chinese navy could have a total of three operational boats of this class by next year, it said.

This new Type 093 variant is expected to enhance the Chinese navy’s anti-surface warfare capability and could provide a land-attack option if equipped with cruise missiles, with China placing a high priority on modernizing its submarine force, the report said.

Meanwhile, the United States has 49 nuclear-powered attack submarines in service, comprising three classes: Los Angeles, Seawolf and Virginia. Four of them are assigned to the naval base in Guam, the U.S.’s westernmost territory.