As North Korea has stepped up the intensity of its missile threats in recent weeks, the U.S. military has strengthened surveillance of the country by deploying four key reconnaissance assets to the Korean Peninsula in quick succession. Reports have come out one after another that two aircraft in particular — the U.S. Air Force's RC-135S "Cobra Ball" special reconnaissance plane and ARES, a next-generation reconnaissance and electronic warfare aircraft — flew over waters off the peninsula's east coast.
On Oct. 3, Voice of America reported, after analyzing data from the flight-tracking site Flightradar24, that the RC-135S "Cobra Ball," the ARES reconnaissance and electronic warfare aircraft and the MQ-9B "SeaGuardian" surveillance drone were flying over the East Sea area when North Korea launched a missile that day.
Earlier, on Sept. 16, the same outlet reported that the Cobra Ball ballistic-missile tracking plane, the P-8A Poseidon maritime patrol aircraft and the ARES reconnaissance and electronic warfare plane were deployed simultaneously over the East Sea, inland areas and the Military Demarcation Line to conduct surveillance of North Korea. It described as unusual the Poseidon's inland reconnaissance and its sweep along the front line, given that the aircraft is designed to detect maritime targets with precision.
What can these four key U.S. reconnaissance assets do? The RC-135 is the U.S. military's flagship electronic reconnaissance aircraft and flies regular missions over the peninsula to monitor developments in North Korea. Missions vary by model, and there are three types: the RC-135V/W "Rivet Joint," the RC-135S "Cobra Ball" and the RC-135U "Combat Sent."
The aircraft track and monitor North Korean ballistic missile launches and military activity. They are operated by the 55th Wing under Air Combat Command. The wing, based at Offutt Air Force Base in Nebraska, is believed to operate 22 reconnaissance aircraft: three RC-135S, two RC-135U, eight RC-135V and nine RC-135W planes.
The RC-135U Combat Sent detects radio signals that appear before and after a missile launch. The RC-135W Rivet Joint specializes in intercepting communications. The RC-135S, nicknamed Cobra Ball, is tasked primarily with monitoring and tracking ballistic missiles and can carry a range of equipment for measurement and signature intelligence. It also mounts special cameras that identify ballistic missiles and track their trajectories.
The ARES reconnaissance and electronic warfare aircraft does more than observe North Korean missile launches visually or by radar. It also collects and analyzes changes in electromagnetic activity, including North Korean communications, electronic signals and radar emissions. ARES is the next-generation reconnaissance plane operated by the U.S. Army in the Indo-Pacific.
It carries 6,350 kilograms of mission equipment and can fly for up to 14 hours at an altitude of 40,000 feet, or about 12 kilometers. It is set to replace the RC-12 Guardrail intelligence, surveillance and reconnaissance aircraft currently operated by U.S. Forces Korea. Development was completed in 2023, as military tension on the peninsula rose, and the aircraft now flies deployment missions over the peninsula from Osan Air Base.
The P-8A Poseidon, called a "submarine killer" and considered the most capable maritime patrol aircraft in service, was developed by Boeing on the airframe of the B737 airliner. It measures 40 meters long, 38 meters wide and 13 meters high, and its two turbofan engines allow it to fly at more than 900 kilometers per hour. It can stay airborne on operations for up to 10 hours.
Because it can fly quickly over the sea to find and attack enemy submarines, it is also known as a submarine hunter. It carries more than 120 sonobuoys that can detect, identify and track submarine signals. It can strike submerged submarines with torpedoes and also carries air-to-ship missiles for precision attacks on surface targets, making it a threat to enemy warships as well.
The aircraft is equipped with high-performance surveillance and electronic warfare systems, including long-range X-band radar that can detect maritime targets hundreds of kilometers away and digital electro-optical and infrared sensors that can capture high-resolution images of targets tens of kilometers out. South Korea's Navy introduced the plane in July 2024 and operates it alongside its older P-3 patrol aircraft, a move analysts say has significantly improved the service's air operations capability.
The MQ-9B "SeaGuardian," another maritime surveillance drone, is designed to stay aloft for 30 to 40 hours while carrying out continuous intelligence, surveillance and reconnaissance missions worldwide. Defense Express, a Ukrainian military news outlet, put the price at 237 million euros (about 357 billion won) per aircraft, saying the SeaGuardian is "more expensive than a Eurofighter."
Its range is reported to reach up to 4,900 kilometers. Japan is said to be moving to acquire MQ-9B SeaGuardian unmanned aerial vehicles for its Maritime Self-Defense Force next year to counter military threats from China. General Atomics is also developing a short takeoff and landing version of the MQ-9B, which India, Taiwan and Australia are seeking to acquire.
