Systems & Submarines- The Case for Evolving Stealth
The MOC
By
Jack Lindstrom
September 29, 2026
Intro
The Jilin-1 satellites rest at the edge of space, utilized by a Chinese research team to track an F-22 through cloud cover, while Chinese scientists watch Starlink’s radio traffic signals to spot a stealth fighter’s forward-scatter shadow. Stealth, designed to enable a prior form of invisible operations in the air, has been unveiled through novel technology. Like sonar detecting the first submarines, the old sensors stealth jets and submarines were designed to evade, be it radar or sonar, are being outflanked by sensors that did not exist during their inception. As technology advances, what once served as stealth warfare has been made visible; the seas under which submarines once hid are now made clear.
There is therefore a divide in the era of stealth warfare, a split in history- all that came before, through submarines with acoustic quieting, stealth aircraft with radar-absorbent shaping, sonar and radar, and new stealth, with unmanned underwater vehicles (UUVs) and artificial intelligence (AI)-fused networks which stitch tapestries of data together.
The Old Stealth
Submarines were perhaps the first purely stealth-synthesized weapons of war, conquering the maritime domain by moving on the vertical axis in a domain otherwise limited to entirely horizontal movements. The invisibility of the oceans provided concealment otherwise absent with the exposure of all vessels on a flat, open arena. Only fog or clever vessel formations created any level of stealth, false-flags and deception, aside from true invisibility. Two detection strategies arose: the acoustic, utilizing passive and active sonar as well as Sound Surveillance System (SOSUS) arrays, detecting the sound of submarines as they move throughout the open ocean to track their location. Then there is the non-acoustic, which utilizes optical, thermal, and magnetic sensors to detect submarines. These non-acoustic techniques arose specifically as submarines evolved to become quieter, utilizing single hull structures to make the vessels swifter and reduce noise. The arms race of sonar against quieting, a battle of constantly evolving technology to detect sound and, in turn, to dampen it, is decades old.
In the skies, the story is much the same, although through radar, rather than sonar. The reduction of radar cross section (RCS) became imperative to the very design of aircraft; the F-22 was designed with a smooth, sloped fuselage, sawtooth-patterned seams on the bay doors and canopy, winding edging ducts, and a fully internal weapons carriage to deflect radar. These jets were built with radar-absorbent material coatings, which have been used since the 1950s to convert radar energy into heat as opposed to reflecting it as light, in turn, making the aircraft invisible on radar. The radar cross section of an F-22 is estimated at 0.0001–0.001 m², the size of a marble or golf ball on radar, while the B-2 is a mere 0.01 m², closer to the size of a phone screen. Non-stealth fighters, by comparison, such as the F-15, have an RCS of 10-25 m², significantly more visible on radar. The design of such aircraft is specifically to avoid radars in the 2-18 GHz range, the common radar range; lower-frequency radars can detect the aircraft; in other words, the stealth fighters are designed against specific sensors, not all radar as a whole. This is because, strategically, a stealth jet optimized for an unused radar frequency is ineffective at its stealth designation- no stealth jet can be optimized against all radar frequencies.
The old stealth, then, was through design strategy as well as domain strategy- the ocean and its depth concealed submarines, while the construction of stealth aircraft was a design against specific radar frequencies and made invisible to the radar it would face in action. In other words, the vehicles of stealth warfare are designed against specific sensors, sensors which have since changed, and have not seen the evolution of the air- and watercraft with it. Instead, novel stealth means have been produced.
The New Stealth
The new era of stealth is one predominantly defined not by novel stealth innovation so much as the innovation of sensors to detect stealth craft. The Jilin-1 satellite constellation has tracked an F-22 flying through clouds with optical intelligence. However, optical systems cannot operate at night and are made blind by clouds or fog; hence, radar is used more universally. The LT-1 system, also a product of China, is such a radar system, a dual-satellite bistatic radar composed of LT-1A and LT-1B, launched in 2022. Produced by the Shanghai Academy of Spaceflight Technology, the chief engineer Chen Junli published simulations displaying how the system can be used to isolate reflected signals from targets with an RCS of around 10 m² viewed aerially. Fifth-generation stealth aircraft could therefore feasibly be tracked by the LT-1 system. It is, however, only simulated at present, and there is no public live tracking the world is yet aware of from the LT-1 system. Nonetheless, similar claims have been made by other Chinese researchers from the State Radio Monitoring Centre utilizing Starlink. The team utilizes a DJI Phantom 4 Pro drone, with an RCS akin to that of an F-22, and demonstrated the ability to detect forward scatter, thus detecting the “ghost” the aircraft casts between a Starlink satellite and a ground antenna, executing a theory that predates Starlink but poses a threat to stealth aircraft.
In the subsea domain, the role of non-acoustic submarine detection has advanced as well. A Northwestern Polytechnical University (NPU) study led by Wang Honglei modeled the surface disturbance submarines create- known as a Kelvin wake- and found that it creates a magnetic field when the ions of the seawater in the wake interact with Earth’s geomagnetic field. For a U.S. Seawolf-class submarine at 24 knots and 30m depth, the wake’s magnetic field is roughly 10⁻¹² tesla- a measure which means little to those outside the scientific defense world, outside of the fact that it is within the range of existing airborne magnetometers. In short, the wakes created by submarines can be sensed and recorded and thereby used to track submarines- and while the submarines can be made quieter, the water they displace and the wakes they, as any object moving in water makes, are unavoidable. Acoustic quieting can do nothing to change the physical act of a ship moving in or under water- and the NPU researchers created a way to detect that kinetic movement.
Additionally, artificial intelligence (AI) has further advanced this evolution of stealth and its detection. Meng Hao of the China Helicopter Research and Development Institute synthesized an AI-driven anti-submarine warfare system which fuses sonar, radar, magnetic anomaly detection, and oceanographic data, of which China has amassed plenty, in real time- which cuts a submarine’s escape probability down to 5%. While this is, like the detection utilizes the LT-1 system, simulated, the potential behind the mechanism is deep cause for concern. AI-enhanced sensors accelerate a shift towards transparent oceans, as such systems detect submarines with what is likely to be increasing accuracy. The technology, although first synthesized in the 1970s through acoustic arrays, has expanded greatly since. This is the newest generation of a transparent ocean strategy to detect submarines, made more viable through unmanned underwater vehicles. While the timeline for transparency is under debate, the advancements of technology only hasten the inevitable revealing of the original stealth domain.
Jack Lindstrom is a Research Fellow with Rise to Peace’s Counterterrorism Fellowship and the founder and publisher of Arctic Ledger, an independent research platform covering Arctic and Antarctic governance, critical minerals, and great power competition. Graduate study in international affairs is underway at the UC San Diego School of Global Policy and Strategy, alongside research work with the Mackinder Forum.
The views expressed in this piece are the sole opinions of the author and do not necessarily reflect those of the Center for Maritime Strategy or other institutions listed.
Center for Maritime Strategy
By Jack Lindstrom
Intro
The Jilin-1 satellites rest at the edge of space, utilized by a Chinese research team to track an F-22 through cloud cover, while Chinese scientists watch Starlink’s radio traffic signals to spot a stealth fighter’s forward-scatter shadow. Stealth, designed to enable a prior form of invisible operations in the air, has been unveiled through novel technology. Like sonar detecting the first submarines, the old sensors stealth jets and submarines were designed to evade, be it radar or sonar, are being outflanked by sensors that did not exist during their inception. As technology advances, what once served as stealth warfare has been made visible; the seas under which submarines once hid are now made clear.
There is therefore a divide in the era of stealth warfare, a split in history- all that came before, through submarines with acoustic quieting, stealth aircraft with radar-absorbent shaping, sonar and radar, and new stealth, with unmanned underwater vehicles (UUVs) and artificial intelligence (AI)-fused networks which stitch tapestries of data together.
The Old Stealth
Submarines were perhaps the first purely stealth-synthesized weapons of war, conquering the maritime domain by moving on the vertical axis in a domain otherwise limited to entirely horizontal movements. The invisibility of the oceans provided concealment otherwise absent with the exposure of all vessels on a flat, open arena. Only fog or clever vessel formations created any level of stealth, false-flags and deception, aside from true invisibility. Two detection strategies arose: the acoustic, utilizing passive and active sonar as well as Sound Surveillance System (SOSUS) arrays, detecting the sound of submarines as they move throughout the open ocean to track their location. Then there is the non-acoustic, which utilizes optical, thermal, and magnetic sensors to detect submarines. These non-acoustic techniques arose specifically as submarines evolved to become quieter, utilizing single hull structures to make the vessels swifter and reduce noise. The arms race of sonar against quieting, a battle of constantly evolving technology to detect sound and, in turn, to dampen it, is decades old.
In the skies, the story is much the same, although through radar, rather than sonar. The reduction of radar cross section (RCS) became imperative to the very design of aircraft; the F-22 was designed with a smooth, sloped fuselage, sawtooth-patterned seams on the bay doors and canopy, winding edging ducts, and a fully internal weapons carriage to deflect radar. These jets were built with radar-absorbent material coatings, which have been used since the 1950s to convert radar energy into heat as opposed to reflecting it as light, in turn, making the aircraft invisible on radar. The radar cross section of an F-22 is estimated at 0.0001–0.001 m², the size of a marble or golf ball on radar, while the B-2 is a mere 0.01 m², closer to the size of a phone screen. Non-stealth fighters, by comparison, such as the F-15, have an RCS of 10-25 m², significantly more visible on radar. The design of such aircraft is specifically to avoid radars in the 2-18 GHz range, the common radar range; lower-frequency radars can detect the aircraft; in other words, the stealth fighters are designed against specific sensors, not all radar as a whole. This is because, strategically, a stealth jet optimized for an unused radar frequency is ineffective at its stealth designation- no stealth jet can be optimized against all radar frequencies.
The old stealth, then, was through design strategy as well as domain strategy- the ocean and its depth concealed submarines, while the construction of stealth aircraft was a design against specific radar frequencies and made invisible to the radar it would face in action. In other words, the vehicles of stealth warfare are designed against specific sensors, sensors which have since changed, and have not seen the evolution of the air- and watercraft with it. Instead, novel stealth means have been produced.
The New Stealth
The new era of stealth is one predominantly defined not by novel stealth innovation so much as the innovation of sensors to detect stealth craft. The Jilin-1 satellite constellation has tracked an F-22 flying through clouds with optical intelligence. However, optical systems cannot operate at night and are made blind by clouds or fog; hence, radar is used more universally. The LT-1 system, also a product of China, is such a radar system, a dual-satellite bistatic radar composed of LT-1A and LT-1B, launched in 2022. Produced by the Shanghai Academy of Spaceflight Technology, the chief engineer Chen Junli published simulations displaying how the system can be used to isolate reflected signals from targets with an RCS of around 10 m² viewed aerially. Fifth-generation stealth aircraft could therefore feasibly be tracked by the LT-1 system. It is, however, only simulated at present, and there is no public live tracking the world is yet aware of from the LT-1 system. Nonetheless, similar claims have been made by other Chinese researchers from the State Radio Monitoring Centre utilizing Starlink. The team utilizes a DJI Phantom 4 Pro drone, with an RCS akin to that of an F-22, and demonstrated the ability to detect forward scatter, thus detecting the “ghost” the aircraft casts between a Starlink satellite and a ground antenna, executing a theory that predates Starlink but poses a threat to stealth aircraft.
In the subsea domain, the role of non-acoustic submarine detection has advanced as well. A Northwestern Polytechnical University (NPU) study led by Wang Honglei modeled the surface disturbance submarines create- known as a Kelvin wake- and found that it creates a magnetic field when the ions of the seawater in the wake interact with Earth’s geomagnetic field. For a U.S. Seawolf-class submarine at 24 knots and 30m depth, the wake’s magnetic field is roughly 10⁻¹² tesla- a measure which means little to those outside the scientific defense world, outside of the fact that it is within the range of existing airborne magnetometers. In short, the wakes created by submarines can be sensed and recorded and thereby used to track submarines- and while the submarines can be made quieter, the water they displace and the wakes they, as any object moving in water makes, are unavoidable. Acoustic quieting can do nothing to change the physical act of a ship moving in or under water- and the NPU researchers created a way to detect that kinetic movement.
Additionally, artificial intelligence (AI) has further advanced this evolution of stealth and its detection. Meng Hao of the China Helicopter Research and Development Institute synthesized an AI-driven anti-submarine warfare system which fuses sonar, radar, magnetic anomaly detection, and oceanographic data, of which China has amassed plenty, in real time- which cuts a submarine’s escape probability down to 5%. While this is, like the detection utilizes the LT-1 system, simulated, the potential behind the mechanism is deep cause for concern. AI-enhanced sensors accelerate a shift towards transparent oceans, as such systems detect submarines with what is likely to be increasing accuracy. The technology, although first synthesized in the 1970s through acoustic arrays, has expanded greatly since. This is the newest generation of a transparent ocean strategy to detect submarines, made more viable through unmanned underwater vehicles. While the timeline for transparency is under debate, the advancements of technology only hasten the inevitable revealing of the original stealth domain.
Jack Lindstrom is a Research Fellow with Rise to Peace’s Counterterrorism Fellowship and the founder and publisher of Arctic Ledger, an independent research platform covering Arctic and Antarctic governance, critical minerals, and great power competition. Graduate study in international affairs is underway at the UC San Diego School of Global Policy and Strategy, alongside research work with the Mackinder Forum.
The views expressed in this piece are the sole opinions of the author and do not necessarily reflect those of the Center for Maritime Strategy or other institutions listed.