Satellite analysis results suggest that China is stockpiling a large number of maritime structures similar to the fixed structures installed in the West Sea Precautionary Measures Zone (PMZ). It appears that China purchased and remodeled oil drilling vessels discarded after use in the Middle East, naming them ‘aquaculture support facilities’ before installation in the PMZ. The discovered facilities have a similar overall structure to the fixed structures in the PMZ, lending credibility to claims that China might have additional installation plans.
On the 13th, the domestic satellite company NaraSpace announced that it confirmed similar structures to the fixed structures installed by China in the PMZ docked at Dalian Port in China, analyzing satellite photos taken by Maxar’s WorldView-3.
The fixed structure that China installed at the western end of the PMZ in October 2022 measures 100 meters in width and 80 meters in length, supported by three steel legs forming a triangular shape. A satellite image taken by Maxar’s WorldView on May 30 shows a distinct ‘H’-shaped helicopter landing pad along with the three steel legs.
◇ Discovery of similar structures to PMZ structures at Dalian Port
China installed a fixed structure resembling an oil drilling facility as a management facility near latitude 35 degrees north and longitude 122 degrees east in October 2022, following the establishment of the ‘Senlan (深藍) No. 1’ deep-sea aquaculture facility at the western end of the PMZ in 2018. Last year, it installed another steel structure named ‘Senlan No. 2’, described as a new aquaculture facility, about 3 kilometers southeast of this fixed structure.
Photos taken by the WorldView satellite on February 17, 2021, showed nine facilities docked within the northern harbor of Dalian Port that exhibit characteristics of the fixed structures captured in the West Sea, including three steel legs and a helicopter pad marked by an ‘H.’
Among the fixed structures, two are near the northern docking facilities while the other seven are clustered at the western docking facilities. This is presumed to be based on China’s plans for mass installation of fixed structures.
In fact, photos captured in April 2024 showed that the number of fixed structures docked at the same harbor had decreased to five. Instead, two were seen being renovated at a presumed dry dock (a facility for repairing ships) next door. Recent footage taken by Airbus for Google Earth on May 17 revealed that five fixed structures were still docked.
Dalian Port is located about 400 kilometers in a straight line from the PMZ facility that has recently been in the spotlight. However, it remains unclear whether the structures in the West Sea were moved there after being renovated at Dalian Port or transferred after modifications at another Chinese port.
This discovery came as the Earthpaper analysis team tracked satellite images related to the West Sea structures and confirmed that the WorldView-3 satellite captured similar facilities in the region for the first time. The WorldView-3 satellite, equipped with a high-performance camera capable of identifying objects measuring 0.31 meters on each side from 617 kilometers above, orbits the Earth every 1 hour and 35 minutes.
◇ West Sea structures also spotted by Arirang satellite
Since 2018, China has installed 13 lighthouse-like structures (buoys) in the West Sea PMZ under the pretext of marine observation. According to confirmation from the navy, 11 of these 13 buoys are identical in size, measuring 13 meters in height and 10 meters in diameter, while the other two are smaller, measuring 5 to 6 meters in height and 5 to 8 meters in diameter.
It appears that site observations as well as satellite resources like the multipurpose practical satellite Arirang were utilized to gather information on the situation. According to the information portal operated by the Korea Aerospace Research Institute (KARI), China has conducted intensive surveillance activities over the areas surrounding the PMZ where structures have been installed, using high-resolution satellites like Arirang-3 and radar imagery satellites such as Arirang-5 and infrared satellites like Arirang-3A in the past two years.
The multipurpose practical satellite Arirang-3, launched in 2012, is equipped with a high-resolution camera capable of identifying objects measuring 0.7 meters on each side. The Arirang-5 satellite, launched in 2013, has synthetic aperture radar (SAR) that monitors the ground even in bad weather. SAR operates by sending radar waves to an object and synthesizing the returning signals to estimate the shape of the object. Typically, iron-made vessels and structures floating on the sea are clearly visible as white dots.
According to an archive that releases photos taken by the Arirang satellites, it appears that Arirang-5 has been focusing on capturing images of structures along the West Sea PMZ area since last year. Footage shot on January 23 of this year shows the fixed structures (large dots) presumably installed by China, a floating structure believed to be Senlan-2 (a long dot in the middle), and fishing boats (small long dots).
The PMZ is an area where the Exclusive Economic Zones (EEZ) of Korea and China overlap, as per the Korea-China fisheries agreement established in 2000, allowing only joint management of fisheries and navigation. The installation of structures is generally prohibited. However, China has bypassed this provision by installing the steel frame platform Senlan-1 in the PMZ on July 2, 2018, and has continuously deployed maritime structures. There are concerns that China’s stance, claiming the West Sea as its jurisdictional waters since 2010, reflects strategic considerations beyond mere fisheries support.
China’s expansion of such activities could potentially act as an unfavorable factor in the recently improving bilateral relations. The government stated it has determined that China plans to install additional structures and is reviewing diplomatic responses. Since the structures installed at sea can be used as a basis for effective control under international law, there is a demand for the government to formulate a clear response strategy. China has a history of asserting its claim by installing oil drilling vessels in its EEZ in the South China Sea.
In April, the Chinese government reportedly suggested on-site investigation plans regarding the structures installed in the PMZ during the third Marine Cooperation Dialogue held in Seoul.
References
NaraSpace Earthpaper, https://ep.naraspace.com/
With the advancement of low-cost space launch vehicles and small satellite technology, we have entered an era where we observe events occurring on Earth in real time. Satellites are now utilized in diverse areas such as defense, disaster and emergency monitoring, damage assessment, and industrial trend analysis. ChosunBiz is serializing a space journalism series titled ‘The World Seen by Satellites’ and ‘The Economy Seen by Satellites’ in collaboration with NaraSpace, a domestic satellite service company, to analyze artificial satellite image data in defense, industry, economy, society, and international reporting.