Ghost Ships Can't Hide:

A Method for Maritime Weak Moving Target Localization Leveraging GNSS-Reflected Baseband Signals and DP-TBD | IEEE Journals & Magazine pular Mechanics

SPECIAL REPORT  |  MARCH 2026  |  MARITIME TECNOLOGY & NATIONAL SECURIT 

Maritime Technology & National Security

How Satellite Navigation Signals Are Becoming the World's Most Powerful Maritime Radar

A thousand rogue tankers are smuggling sanctioned oil across the world's oceans with their transponders dark. Scientists and engineers have invented an unexpected weapon to find them — the same GPS signals guiding your phone.

By Popular Mechanics Staff  |  March 16, 2026  |  Based on peer-reviewed research, official government reports, and investigative reporting

BLUF

A shadow fleet of more than 1,900 tankers — operated by Russia, Iran, and Venezuela — is systematically disabling AIS tracking transponders and spoofing GPS locations to evade Western sanctions. They move an estimated $87–100 billion in oil annually. Researchers at Tianjin University, the University of Birmingham, Sapienza University of Rome, and elsewhere have now demonstrated that GNSS-based passive radar — a system that uses reflected GPS, Galileo, and BeiDou satellite navigation signals as an entirely passive, non-cooperative radar — can detect, track, and localize ships that have "gone dark" to ranges exceeding one kilometer, with position accuracy better than 42 meters, updated every second. The technology requires no transmitter, is virtually undetectable, operates in any weather, and leverages an infrastructure of more than 140 satellites already in orbit. When combined with SAR satellite imagery, RF emission detection, and AI analytics, GNSS passive radar may close the maritime surveillance gap that rogue states have been exploiting since 2022.

The Invisible Fleet

On a November afternoon in 2025, the oil tanker Guru was passing through the English Channel — one of the most heavily monitored shipping lanes on the planet — when it simply vanished. Its Automatic Identification System (AIS) transponder went silent, and for roughly ten hours the vessel left no trace as it traveled some 200 kilometers through waters crisscrossed by coast guard radar, satellite receivers, and port authority tracking networks.[14] When it reappeared near Calais, it resumed its journey toward the Russian port of Vysotsk, its cargo of sanctioned crude never officially recorded in transit.

The Guru is far from alone. According to Windward, a maritime analytics firm, more than 1,900 vessels were operating as part of the so-called dark fleet by the third quarter of 2025 — a clandestine armada of tankers transporting oil from Russia, Iran, and Venezuela in violation of sweeping U.S. and European Union sanctions.[12] In the first eight months of 2025 alone, investigators recorded more than twice as many significant AIS blackout events among Russia-linked vessels compared to the first year of the war in Ukraine, with Russia-connected ships experiencing six times as many extended outages as comparable European vessels.[14] The scale of the deception is staggering: Russia's ghost fleet alone is estimated to transport 3.7 million barrels of oil per day — roughly 65 percent of that country's seaborne oil trade — generating between $87 billion and $100 billion annually for the Kremlin's war machine.[17]

The technology enabling this concealment is disturbingly simple. Ships can power off their AIS transponder with a single switch. More sophisticated operators feed false GPS coordinates into the transponder — allowing a tanker to appear to be docked at a legitimate port in the United Arab Emirates while it is actually loading sanctioned crude at an Iranian terminal.[8] By Q1–Q3 2025, Windward data showed more than 24,000 vessels experiencing GPS jamming, with AIS location "jumps" averaging 6,300 kilometers.[11]

The Shadow Fleet by the Numbers (Q3 2025)

• 1,900+ vessels actively operating as dark/shadow fleet tankers

• 636 tankers sanctioned by Western governments (U.S., EU, UK)

• 3.7 million barrels/day moved by Russia's ghost fleet alone

• $87–100 billion estimated annual revenue for Russia

• 24,000+ vessels experienced GPS jamming in Q1–Q3 2025

• 72% of Iran-linked shadow vessels shut off AIS for prolonged periods in 2025

• 77% of Iran-linked shadow vessels spoofed their location in 2025

• 70%+ of sanctioned vessels changed flags during 2025

Sources: Windward Maritime AI, Kpler, CSIS, Follow the Money investigative reporting

Enforcement has struggled to keep pace. The Biden administration sanctioned 183 tankers in its final days in early 2025. The Trump administration followed with sweeping additional sanctions on Iran-linked networks in February 2025 and launched "Operation Southern Spear," seizing at least 10 tankers since December 2025.[15] France seized the tanker Grinch in the Mediterranean. India — under pressure from Washington — detained three Iranian oil vessels off its coast.[21] But for every vessel seized, dozens more slip through the net. Traditional maritime surveillance tools — shore-based radar, satellite AIS receivers, even commercial synthetic aperture radar (SAR) imagery — all have gaps. And when ships go completely dark, the oldest detection method on Earth — eyesight from the deck — is worthless.

The answer, researchers now believe, may be hiding in plain sight — or rather, it's raining down from the sky, invisibly, right now, everywhere on Earth.

Radar From Nowhere: The GNSS Passive Radar Concept

Conventional radar works by broadcasting a powerful radio pulse and listening for the echo. Passive radar skips the transmitter entirely, borrowing its energy from whatever radio-frequency signals happen to be illuminating the scene — broadcast television towers, FM radio stations, cellular networks. The radar receiver listens for the faint reflections of those "signals of opportunity" bouncing off targets of interest. No transmitter means no electromagnetic footprint, no high-power electronics, and dramatically reduced cost and size.

GNSS-based passive radar takes this concept to its logical extreme. The transmitters are the navigation satellites — GPS (U.S.), Galileo (EU), BeiDou (China), and GLONASS (Russia) — orbiting at roughly 20,000 kilometers altitude, broadcasting L-band signals continuously, globally, in all weather, around the clock. With more than 140 operational satellites across the four major constellations, the illumination is essentially ubiquitous.[1] A ship at sea is bathed in these signals whether its crew knows it or not — and whether its AIS transponder is on or off is completely irrelevant.

The physics are elegant. A ship on the ocean surface intercepts a fraction of the GNSS signal energy and scatters it in all directions. A receiver on a nearby shore, buoy, or platform captures both the direct satellite signal and the reflected signal from the ship. By comparing the two — correlating the known code structure of the direct signal against the time-delayed, Doppler-shifted reflection — the receiver can measure the total path length from satellite to ship to receiver (the bistatic range) and the ship's velocity. With measurements from three or more satellites, basic geometry pins down the ship's three-dimensional position — no cooperation from the vessel required, no transmitter needed, no give-away RF emissions, no dependence on weather or daylight.

How GNSS Passive Radar Detects a Dark Ship

GPS/GAL SAT 1 BDS/GLO SAT 2 GPS/GAL SAT 3 AIS: OFF DARK VESSEL RECEIVER DIRECT+REFLECT Bistatic ellipsoid intersection pinpoints vessel position (≥3 sats) GNSS illumination Reflected signal Direct reference

The principle has been understood for decades, but the practical challenge is immense. GNSS signals were designed to navigate smartphones and aircraft, not to illuminate targets for radar. They carry a mere 20–50 watts of transmit power — thousands of times weaker than a dedicated maritime radar. The reflected signal from a ship reaches the receiver at a signal-to-noise ratio that can be 60 decibels below the noise floor — that is, the signal is one-millionth the strength of the surrounding electronic noise.[1] Conventional signal processing fails completely under such conditions.

The Breakthrough: DP-TBD and Baseband Processing

The most recent advance comes from a team at Tianjin University's School of Marine Science and Technology, whose paper appeared in the IEEE Geoscience and Remote Sensing Letters on March 9, 2026.[1] Their technique, developed by Zhikun Zhang, Bofeng Guo, Yang Nan, Yulin Han, and Xiang Wu, addresses the two principal bottlenecks that have held back GNSS passive radar for maritime surveillance: the abysmally low signal power budget and the inherently slow position update rate of prior approaches.

Instead of building a traditional range-Doppler map — the standard radar representation requiring long, computationally expensive coherent processing intervals — the Tianjin team works directly with the GNSS baseband signal. Each 1-millisecond code period of the GPS L5 or BeiDou-3 B2a signal is correlated against the reference signal, and those 1,000 one-millisecond outputs are incoherently stacked over one second to build what the researchers call a bistatic range–slow-time (BRST) map. A Keystone transform corrects for range cell migration — the smearing that occurs when a moving ship drifts across range cells during the integration window.[1]

The real magic, however, is the Dynamic Programming Track-Before-Detect (DP-TBD) algorithm applied to the BRST map. Track-before-detect techniques treat the problem of finding a buried signal not as a detection problem (is the target here?) but as a tracking problem (where has the target been?). By threading together the faint signal energy across multiple sequential time frames — exploiting the fact that a real ship must move continuously and smoothly — DP-TBD can reconstruct a target's bistatic range history even when no individual frame contains a detectable return. In the Tianjin experiments, the algorithm successfully extracted ship trajectories at SNRs as low as −62 dB.[1]

The ship turned off its AIS and thought it disappeared. It was still being illuminated by GPS satellites it couldn't jam, couldn't spoof, and couldn't shut off.

— Principle underlying GNSS passive radar detection

The results in actual field experiments were striking. In the first scenario, a small construction vessel just 26 meters long was tracked at a range of approximately 160 meters from the receiving station, using four GPS satellites and three BeiDou-3 satellites simultaneously. The position root-mean-square error (RMSE), validated against AIS data, was just 13.15 meters — a relative error of less than 8 percent. In the second scenario, a large 300-meter cargo ship at 1,100 meters range was tracked with an RMSE of 41.52 meters. Critically, both tracks were updated at 1 Hz — once per second — compared to the two-to-five second update rates of conventional range-Doppler approaches. Compared to traditional RD-based methods, localization accuracy improved by 38.4 percent and 18.4 percent in the two scenarios respectively.[1]

The Tianjin work builds on a foundation of experimental research stretching back over a decade. A landmark 2018 paper in IEEE Transactions on Geoscience and Remote Sensing by Ma, Antoniou, Stove, Winkel, and Cherniakov at the University of Birmingham demonstrated that large vessels could be localized using passive GNSS-based multistatic radar through elliptical positioning derived from range-Doppler maps.[6] The same group subsequently showed that GNSS signals could generate coherent radar imagery of ship targets — enabling not just detection and localization, but noncooperative ship classification.[10] Using Galileo E5a signals, researchers imaged vessels including a 173-meter ferry and correctly estimated its length to within four meters.

European researchers at Sapienza University of Rome demonstrated the technology's versatility across multiple environments. In a 2020 paper in MDPI Sensors, Santi and colleagues showed successful detection of ships in port operations, open-water navigation, and river traffic on Germany's Rhine — tracking vessels ranging from 39-meter passenger ships to 110-meter motor tankers, in each case with track results consistent with simultaneous AIS ground truth data.[4] The receiver, mounted in a van on the shore, required no special infrastructure beyond a standard-gain antenna — a system that could be deployed on a buoy, a coast guard vessel, an unmanned surface vehicle, or an aircraft.

The Satellite Angle: Taking GNSS Radar to Space

Ground-based GNSS passive radar, while powerful, faces the same horizon limitation as any shore-based system. The real prize is spaceborne operation — a receiver in low Earth orbit (LEO) capturing GNSS reflections from the ocean surface below.

This is not speculation. NASA's Cyclone Global Navigation Satellite System (CYGNSS) mission, an eight-satellite constellation launched in 2016, uses GNSS reflectometry to measure ocean surface roughness and wind speed from LEO.[31] Researchers at NTNU and other institutions have demonstrated proof-of-concept ship detection using data from the UK TechDemoSat-1 mission, showing that large structures including ships and oil production platforms produce clearly detectable signatures in spaceborne GNSS-R data.[23] ESA launched its PRETTY (Passive REflecTomeTry and dosimetrY) satellite in October 2023 specifically to advance GNSS-R altimetry from orbit.[31]

The implication is significant. A dedicated LEO constellation of GNSS-R receivers — potentially small, inexpensive CubeSats — could provide persistent, global maritime surveillance without any cooperative signal from vessels. Every ship, dark or lit, would be bathed in reflected navigation signals that betray its position, velocity, and even its size. China's Bufeng-1 A/B and the operational FY-3/GNOS-II mission demonstrate that multiple countries are already investing in space-based GNSS-R infrastructure.[31]

Current GNSS-Based Passive Radar Performance (2026)

• Detection range: demonstrated from 160 m (26 m vessel) to 1,100 m (300 m vessel) from shore

• Position accuracy (RMSE): 13–42 meters, validated against AIS ground truth

• Update rate: 1 Hz (once per second) — up to 5× faster than RD-map methods

• Minimum detectable SNR: −62 dB (with DP-TBD processing)

• Satellites used: GPS L5, BeiDou-3 B2a, Galileo E5a (L-band, ~1176 MHz)

• Transmitter required: None — entirely passive reception

• Operator detectability: Near-zero — no emissions from receiver

• Weather dependence: None — L-band signals penetrate cloud cover

• Ship cooperation required: None — AIS status irrelevant

Source: Zhang et al., IEEE GRSL, March 2026; Santi et al., MDPI Sensors, 2020; Ma et al., IEEE TGRS, 2018

The Layered Solution: Fusing Technologies to Close Every Gap

No single technology catches every vessel every time. The emerging paradigm in maritime domain awareness (MDA) is sensor fusion — layering complementary detection modalities so that a ship evading one system is caught by another.

Commercial SAR satellite imaging — from companies like ICEYE, Airbus Defence and Space, and Maxar — can detect ships by their radar backscatter independently of any cooperative signal. SAR works day and night and through cloud cover, though revisit rates of commercial constellations are measured in hours to days, not seconds, and imagery costs limit systematic global coverage.[7] ICEYE and Spire Global have partnered to cross-correlate SAR imagery with satellite AIS, flagging any vessel in a SAR image that lacks a corresponding AIS transmission as a potential dark vessel.[7]

RF emission detection satellites take a different approach. French company Unseenlabs has deployed a constellation of 15 satellites — expanding to 25 by end of 2025 — that detect and geolocate the radio frequency emissions of ships' own navigation radars and communication equipment.[38] Even a vessel with AIS off still radiates RF energy from its X-band navigation radar, its VSAT communications terminal, its engine monitoring systems. Unseenlabs achieves geolocation accuracy within one kilometer and covers areas up to 300,000 square kilometers per satellite pass.[38] A similar capability is fielded by HawkEye 360, which geolocates VHF, UHF, and L-band emissions from orbit. The Norwegian NorSat-3 satellite carries a navigation radar detector with the same goal.[34]

The limitation of RF detection is that it requires the ship to be emitting something — and a vessel that has shut down its navigation radar, satellite communications, and AIS simultaneously can go truly dark. This is precisely where GNSS passive radar offers a decisive advantage: it imposes no requirement on the ship whatsoever. GPS signals illuminate every surface vessel, whether it is actively emitting anything or not.

AI-driven behavioral analytics from firms like Windward and Global Fishing Watch complete the picture, correlating vessel track histories, port call sequences, flag registry records, and ownership opacity against known patterns of sanctioned trade to identify suspicious activity even when position data is intermittent.[2,12] A 2023 study using satellite SAR and AIS fused with AI models found that AIS alone missed nearly 90 percent of vessels detected by satellite radar within Marine Protected Areas — underscoring the essential role of non-cooperative sensors.[2]

The Enforcement Landscape: A Chess Match at Sea

The escalating enforcement campaign against the dark fleet has produced a cat-and-mouse dynamic that shows no signs of resolution. Western governments have sanctioned more than 900 shadow fleet vessels since Russia's 2022 invasion of Ukraine.[21] In response, vessel operators have adopted increasingly sophisticated evasion: renaming ships, flag-hopping between permissive registries, using shell company ownership chains, and shifting to outright stateless operation after registries are pressured to delist them.[19]

In an alarming development reported in early 2026, nearly 70 dark fleet tankers began reflagging to Russia directly — a move that restores legal protection under international maritime law and complicates interdiction under established treaty frameworks.[18] The U.S. seizure of sanctioned tanker Skipper in a Caribbean military raid following AIS spoofing detection demonstrated that enforcement is willing to act aggressively when intelligence is solid — but also illustrated the legal and logistical complexity of interdicting a vessel on the high seas.[8]

CSIS analysts note that while ship seizures send a deterrent signal, the most durable enforcement strategy is likely targeting the financial and logistical enablers — the insurers, flag registries, ship managers, and traders that sustain the shadow fleet's operations.[17] The Middle East Institute estimates that around 300 million barrels remain unsold on shadow tankers at sea, suggesting the threat of enforcement is beginning to bite — but the fundamental plumbing of the evasion ecosystem remains intact.[15]

The dark fleet isn't disappearing — it's becoming more offshore, more fragmented, and more behaviorally extreme.

— Maritime analyst, quoted in CNBC, February 2026

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Strategic Intelligence Sidebar Analyst Assessment  ·  Dual-Use Technology Risk

The Other Side of the Coin: Does Iran Already Have This Technology?

The Tianjin University paper is authored by researchers at a Chinese state institution, funded by China's National Key Research and Development Program — a dual-use funding stream that explicitly bridges civilian and military applications. That provenance, combined with the well-documented Iran–China defense technology transfer relationship, raises a question that Western naval planners should be asking seriously: could Iran already possess, or be rapidly acquiring, GNSS passive radar capability for use in the Strait of Hormuz?

The China–Iran Technology Pipeline

China and Iran signed a 25-year comprehensive cooperation agreement in 2021 explicitly covering defense, intelligence, and technology transfer. Chinese radar systems, drone components, and signals intelligence technology are documented in IRGC inventories. In China's Military-Civil Fusion (MCF) framework — to which Tianjin University is subject — the administrative distinction between civilian maritime surveillance research and military coastal defense capability is largely nominal. Tianjin University appears on the U.S. Department of Commerce Entity List for dual-use technology research areas. The pathway from a published IEEE paper to an IRGC Electronic Warfare unit briefing is shorter than Western analysts typically acknowledge.

Why Hormuz Is the Perfect Use Case

Iran's primary strategic asset is its position along the northern shore of the Strait of Hormuz — one of the world's most critical maritime chokepoints. Its primary threat scenario involves U.S. naval forces suppressing Iranian coastal radar using HARM anti-radiation missiles, EA-18G Growler jamming aircraft, and cyber means before transiting carrier strike group assets through the strait. A passive, non-emitting coastal surveillance system that cannot be targeted by anti-radiation missiles, cannot be located by passive RF detection, and does not depend on AIS cooperation is precisely what Iranian planners would want. The Chinese researchers have essentially published the engineering manual for that system.

The BeiDou Asymmetry

A GNSS passive radar system built around China's BeiDou constellation rather than GPS would be immune to U.S. GPS jamming operations in the strait — a capability the U.S. has demonstrated extensively in the Middle East theater. China has overwhelming economic incentive to keep BeiDou signals operating normally during any Hormuz conflict: Iranian oil flows to China, and BeiDou jamming in support of a U.S. operation against Iran is politically inconceivable. Iran could field a BeiDou-only passive surveillance network that U.S. electronic warfare assets cannot blind without Chinese cooperation that will never come.

What "Probably Has It" Realistically Means

• Access to the full published literature and likely direct technical briefings from Chinese counterparts

• Software-defined radio and signal processing hardware sufficient to implement the receiver chain

• IRGC Electronic Warfare Organization engineers with the expertise to operationalize it at small scale

• Strong motivation: the tactical value in a radar-suppressed Hormuz scenario is obvious to any competent signals engineer

• Islands already controlled by Iran in the strait (Abu Musa, Greater and Lesser Tunb) provide ideal distributed receiver station locations covering the full navigable width

The gap between "has the technology" and "has an operationally deployed networked system covering the strait" is real — but probably measured in months to a few years of systems integration work, not a fundamental engineering barrier. The publication of this paper in March 2026 may itself mark a threshold: the technique is now fully described, experimentally validated, and openly available to any nation's defense research establishment.

The Uncomfortable Policy Implication

The U.S. national security community has focused heavily on semiconductor and AI technology transfer controls. The quieter transfer of passive sensing and signals processing techniques through the open academic literature — research funded by China's MCF programs and published in internationally distributed IEEE journals — receives far less scrutiny and is considerably harder to control. This paper is a case study in that gap. The same physics that enable dark fleet enforcement enable dark fleet–style evasion of naval surveillance — and the engineering manual is now publicly available to anyone who downloads it from IEEE Xplore.

Analysis based on open-source intelligence, published academic literature, and U.S. government entity list designations. This assessment represents analytical inference, not confirmed intelligence.

Limitations and the Road Ahead

GNSS passive radar is not yet a deployed operational system. The current demonstrated ranges — a few kilometers from shore — are sufficient for port approaches and coastal waters but not for monitoring vessels in open ocean. Extending the detection range requires either more sensitive receivers, more sophisticated processing algorithms, higher-gain antennas, or moving the receiver to a satellite platform. All are active research areas.

The technology also cannot yet fully replace AIS as an identification system. It can detect that an object is present and track its motion, but associating that track with a specific vessel identity — the Guru rather than a legitimate fishing boat — still requires correlation with other data sources. Passive ISAR imaging (inverse synthetic aperture radar using GNSS signals) has shown promise for estimating vessel dimensions and providing a crude shape image,[10] but ship identification from imagery alone remains an unsolved challenge.

There are also geopolitical complications. Three of the four major GNSS constellations are controlled by powers that have strategic interests in the dark fleet's continued operation: Russia's GLONASS supports the fleet evading Russia's own nation's sanctions; China's BeiDou serves a country that is the primary buyer of sanctioned Russian and Iranian crude. It is unlikely that either country would interfere with their own navigation satellites — doing so would harm their own civilian infrastructure — but the dependence on foreign-controlled infrastructure is a vulnerability worth noting.

The technical trajectory, however, is clearly toward capability. Processing algorithms improve with each publication cycle. CYGNSS and TechDemoSat-1 have proven the spaceborne concept. Commercial GNSS receiver chipsets are increasingly capable of tracking multiple constellations simultaneously, providing the multi-satellite diversity that localization requires. The Tianjin University result — 1-Hz position updates at better than 42-meter accuracy, from a passive receiver requiring no transmit infrastructure, using signals already in the sky — represents a significant step from laboratory curiosity to operational potential.

Conclusion: The Sky Is Watching

For decades, the basic bargain of maritime tracking was straightforward: a ship that wanted to be seen broadcast its position, and a ship that wanted to hide simply stopped broadcasting. The Automatic Identification System was always cooperative by design, and that cooperativeness was always its fatal flaw. A thousand rogue tankers have exploited that flaw to move $100 billion worth of sanctioned oil and fund an ongoing war in Europe.

The emerging generation of non-cooperative sensing technologies — GNSS passive radar, SAR imaging, satellite RF detection, AI behavioral analytics — is fundamentally changing that calculus. The most consequential of these may prove to be GNSS passive radar, because it makes visibility a physical fact rather than a choice. You cannot turn off GPS. You cannot jam GPS without also destroying your own navigation capability. You cannot spoof the reflections of a signal you didn't generate. A ship illuminated by navigation satellites from space will leave traces in reflected electromagnetic energy whether its crew wants it to or not.

The dark fleet has found the cracks in a cooperative tracking system. The answer being built, piece by piece in labs from Tianjin to Birmingham to Rome, uses the laws of physics rather than the cooperation of ship owners — and in that asymmetry may lie the future of maritime enforcement.

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Verified Sources & Formal Citations

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30. Ursa Space Systems & Unseenlabs. (2022, September 15). "Ursa Space and Unseenlabs Partner to Support Maritime Stakeholders in Dark Vessel Detection." Press Release. https://ursaspace.com/blog/ursa-space-and-unseenlabs/

31. Ma, H., Antoniou, M., Pastina, D., et al. (2018). "Maritime Moving Target Indication Using Passive GNSS-Based Bistatic Radar." IEEE Transactions on Aerospace and Electronic Systems, 54(1), 115–130.

32. Grossi, E., Lops, M., & Venturino, L. (2013). "A Novel Dynamic Programming Algorithm for Track-Before-Detect in Radar Systems." IEEE Transactions on Signal Processing, 61(10), 2608–2619.

 

Systems Engineering Imperatives for Reusable Orbital Launch Vehicles:

Journal of Systems Engineering Practice

Vol. 12  ·  No. 1  ·  March 2026
ISSN 2835-4108  ·  DOI: 10.XXXX/JSEP.2026.03.001

Review Article  ·  Space Transportation Systems

Architecture, Lifecycle Fidelity, and the Emerging Digital Thread

Rapid booster reuse has transformed launch economics, but the deeper systems engineering challenge — integrating thermal protection health, structural prognostics, regulatory compliance, and cross-domain Model-Based Systems Engineering across a vehicle's operational life — remains incompletely solved. This article surveys the current state of the art, identifies unresolved problems, and outlines a path toward fully integrated lifecycle management for orbital-class reusable systems.

Submitted February 2026

Accepted March 2026

Keywords RLV · MBSE · TPS · IVHM · SHM · digital twin

Bottom Line Up Front (BLUF)

Reusable orbital launch vehicles have already achieved dramatic cost reductions — SpaceX's Falcon 9 now accounts for more than half of all global orbital launches, with a single booster demonstrating 33 flights and a record nine-day turnaround — yet the systems engineering discipline supporting multi-flight certification, thermal protection health management, rapid ground processing, and regulatory compliance frameworks has not kept pace with operational tempos. Model-Based Systems Engineering (MBSE) integrated with digital twin technology represents the most promising path forward, providing continuous lifecycle traceability from conceptual sizing through high-flight-count operations. Practitioners should treat reusability not as a design feature but as a systems-level property that must be engineered from trade-space definition through retirement, with full-fidelity Integrated Vehicle Health Management (IVHM) as its operational backbone.

The operational realities of reusable orbital launch vehicles have outpaced the systems engineering methodologies originally developed to support them. When NASA's Advanced Concepts Office at Marshall Space Flight Center developed the analytical frameworks described in the SSEC proceedings — using tools such as INTROS, LVA, and POST alongside the PARSEC collaborative environment — the underlying assumption was that a vehicle would fly once, or at most a small number of times, before undergoing substantial refurbishment or retirement. The paradigm shift introduced by commercially developed reusable first stages, and now emerging fully reusable two-stage systems, demands a fundamental re-examination of how systems engineers define, verify, and sustain the concept of "airworthiness" across dozens or hundreds of flights.

This article synthesizes recent developments in operational reusable launch vehicles, thermal protection systems engineering, structural health monitoring, Model-Based Systems Engineering adoption, digital twin integration, and the regulatory landscape to provide a comprehensive view of where the discipline stands in early 2026 — and what must be done next.

1. The Operational Landscape: Reusability as an Industrial Reality

As of early 2026, the reusable launch vehicle industry has achieved a scale that would have seemed implausible a decade ago. The FAA found that more than 60% of all orbital launches in 2024 involved some reusable technology.^[1] SpaceX's Falcon 9 and Falcon Heavy rockets completed 134 total flights in 2024 — the most by any launch provider in a single year, accounting for more than half of all launches worldwide.^[2] A single Falcon 9 booster, B1067, has now flown 28 times, well exceeding the original ten-flight certification target set when the Block 5 variant debuted in 2018.^[3] Most dramatically, booster B1088 achieved a turnaround from landing to next launch in nine days, three hours, and 39 minutes in March 2025 — a figure that would have been dismissed as operationally impossible under prior assumptions about post-flight refurbishment.^[4]

Blue Origin entered the orbital reusable category meaningfully in November 2025, when its New Glenn rocket successfully landed its first stage on a drone ship in the Atlantic following its second flight, making Blue Origin only the second company after SpaceX to accomplish propulsive recovery of an orbital-class booster.^[5] In China, Deep Blue Aerospace and at least eight other startups are developing partially reusable vehicles, with nine Chinese firms planning rocket debuts in the near term, at least half developing partially reusable designs.^[6] India's ISRO completed its third and final glide test of the Pushpak reusable spaceplane in 2024 and is now targeting an orbital launch and return mission.^[6]

Table 1. Selected Operational Reusable Launch Vehicle Programs as of Q1 2026

Vehicle	Developer	Reusable Stage(s)	Notable Milestone	Status
Falcon 9 Block 5	SpaceX (USA)	First stage, fairings	33 flights, single booster; 9-day turnaround	Operational
Falcon Heavy	SpaceX (USA)	All three cores	Synchronized side-booster recovery	Operational
Starship / Super Heavy	SpaceX (USA)	Both stages (target)	Mechazilla booster catch; 11 integrated flights through Oct. 2025	Development/Test
New Glenn	Blue Origin (USA)	First stage	First propulsive landing Nov. 2025	Early operations
Nova	Stoke Space (USA)	Both stages (target)	Space Force OSP-4 contract award	Development
Long March 12A	CASC (China)	First stage (target)	Maiden flight Dec. 2025; stage lost on landing	Development
Pushpak RLV	ISRO (India)	Winged orbiter	Third glide test complete 2024	Development

The global reusable launch vehicle market was valued at approximately USD 4.77 billion in 2025, with North America holding a 38.7% market share.^[7] Projections for the broader space launch services market reach USD 57.94 billion by 2033 at a compound annual growth rate of 13.15%.^[1] Mega-constellations are a primary driver: the Satellite Industry Association reported that 4,562 low-Earth-orbit satellites were launched in 2024 alone, with projections of up to 50,000 by 2030.^[1]

2. Systems Engineering Challenges Unique to Reusable Vehicles

The fundamental systems engineering challenge of a reusable orbital launch vehicle is different in kind, not merely degree, from that of an expendable system. An expendable vehicle must be verified as safe for exactly one flight. A reusable vehicle must be verified as safe for flight N, conditioned on the history of flights 1 through N–1 and the results of intervening inspections and refurbishments. This introduces a time-evolving, state-dependent reliability model that conventional design-time analysis cannot fully capture.

2.1 Thermal Protection Systems

The Thermal Protection System remains the most demanding subsystem in reusable vehicle design. The requirement is formidable: a TPS must be lightweight, durable, operable, and reusable, ideally for at least 100 missions, while exhibiting an order-of-magnitude reduction in maintenance and inspection requirements relative to the Space Shuttle orbiter's TPS — which required extensive labor-intensive tile inspection and replacement between flights.^[8] The Space Shuttle experience demonstrated that TPS systems covering various parts of the orbiter were repeatedly exposed to temperatures beyond their true reuse limits, causing embrittlement, edge slumping, and coating cracking — a lesson that must inform all subsequent designs.^[8]

Modern research has moved toward a multi-material, zone-specific TPS philosophy. At temperatures above 1700 K, carbon/silicon carbide composites are required; alumina ceramic matrix composites handle engine heat shields up to 1850 K; and lighter metallic thermal protection panels using gamma-titanium aluminide serve lower-temperature leeward surfaces below 1100 K.^[9] The superalloy honeycomb TPS concept — a foil-gauge metallic box encapsulating low-density fibrous insulation — is being actively improved for reusable launch vehicle applications, with efforts focused on more efficient internal insulation, lighter weight configurations, and quick-release fastener systems that allow rapid field replacement.^[10]

The 2025 AIAA Aviation Forum highlighted a new generation of "smart TPS" approaches that integrate adaptive materials, embedded sensor networks, and AI-driven analytics to enable real-time thermal management and structural adjustments across reusable spacecraft, hypersonic vehicles, and deep-space mission vehicles.^[11] Aerogels, phase change materials, and ultra-high-temperature ceramics are now being evaluated as lightweight high-performance solutions for next-generation vehicles. Despite progress, challenges in integration, testing, and scalability persist, particularly in self-healing material systems and autonomous thermal management.^[11]

2.2 Structural Health Monitoring and Integrated Vehicle Health Management

The loss of Space Shuttle Columbia in 2003 highlighted in the starkest possible terms the consequences of inadequate in-flight structural health monitoring (SHM). Investigators examined more than 30,000 documents, conducted more than 200 formal interviews, heard testimony from dozens of expert witnesses, and reviewed thousands of public inputs — a process that ultimately concluded with a call for fundamentally better TPS inspection capabilities.^[12] Among the non-destructive evaluation methods subsequently developed, advanced digital radiography, high-resolution computed tomography, thermographic principal component analysis, and eddy current array scanning demonstrated maturity sufficient for application to critical structural panels.^[12]

Future reusable vehicles will require a step-change beyond post-flight inspection to continuous in-situ SHM using large arrays of onboard sensors feeding Integrated Vehicle Health Management (IVHM) systems. Advanced data architectures capable of communicating, storing, and processing massive quantities of heterogeneous sensor data will be necessary, along with structural analysis algorithms that incorporate SHM sensing into design and construction from the outset — and ultimately provide not just diagnosis but prognosis of structural integrity for flight certification decisions.^[13] Digital Bayesian network-based frameworks coupled with deep learning have demonstrated crack propagation prediction with final errors below 8%, validating the approach for life-prediction in aerospace structural components.^[14]

"It is still incumbent on the systems engineers to communicate and foster collaboration that will enable the studies to be completed with acceptable results." — Reginald Alexander, NASA MSFC Advanced Concepts Office

2.3 The Two-Stage Reusability Engineering Divide

The industry is currently split between two philosophical camps in upper-stage reusability. The "airplane-like reflight" approach pursued by SpaceX for Starship involves an entire upper stage returning to Earth using a heavy thermal protection system and aerodynamic surfaces — a configuration that creates an inherent tension between payload capacity and recovery hardware mass, since the vehicle must carry the weight of its heat shield and landing propellant throughout ascent.^[15] The alternative "modular recovery" philosophy focuses on recovering only the highest-value components — engines, avionics — while treating tankage as expendable. Both approaches carry distinct systems engineering implications for mass budgeting, reliability modeling, and ground processing architecture. The recent Falcon 9 upper-stage deorbit failure in February 2026, which temporarily grounded the fleet, underscored that even "expendable" second stages introduce systemic risk requiring careful configuration management and failure mode engineering.^[15]

3. Model-Based Systems Engineering and the Digital Thread

The transition from document-centric systems engineering to Model-Based Systems Engineering (MBSE) represents the most significant methodological shift in the field in the past two decades, and it is particularly consequential for reusable vehicle programs where design traceability and lifecycle continuity are paramount. MBSE uses graphical, dynamic, and executable models as the primary means of information exchange — replacing static documents with living representations of system requirements, architecture, behavior, and verification status that can be continuously updated as vehicle configuration evolves across its operational life.^[16]

By 2025, MBSE has matured from a niche research methodology into an operational standard across aerospace, automotive, and defense industries. INCOSE has formalized MBSE practices into globally adopted standards, and major programs including NASA's Mars Curiosity Rover mission have demonstrated MBSE as an effective mechanism for ensuring system safety and cross-subsystem consistency in complex space systems.^[17] The 2025 MBSE Symposium held in Huntsville, Alabama — co-located with digital engineering workshops sponsored by Dassault Systèmes — reflected the depth of institutional investment now directed at scaling MBSE across complex multi-domain programs.^[18]

The integration of MBSE with digital twin (DT) technology represents the frontier of systems engineering practice for reusable vehicles. A digital twin is an interactive, real-time digital representation of a physical system that uses onboard sensor data and telemetry to maintain synchronization with the physical asset.^[19] For a reusable launch vehicle, a properly configured digital twin would continuously update the vehicle's structural model with flight-by-flight load measurements, TPS temperature history, propulsion cycles, and landing impact data — enabling probabilistic certification decisions that account for actual vehicle history rather than worst-case design assumptions.

A 2025 systematic review published in the Systems Engineering journal identified two principal categories of DT–MBSE integration: MBSE-based digital twins, where MBSE models serve as the foundation for constructing the twin; and digital twins that use MBSE system models as reference architectures for data interpretation.^[20] The review noted that integrating DT development with MBSE can introduce system-of-systems complexity, particularly when third-party or legacy components are involved, requiring careful attention to model governance and version control.^[21]

Analytical Framework Note

The MSFC Advanced Concepts Office's PARSEC environment — described in the foundational systems analysis literature and now archived at the NASA Technical Reports Server — provided an early precedent for collaborative, database-centered design environments in which analysts from multiple disciplines contribute to a shared project database while maintaining individual analytical workspaces. The conceptual architecture of PARSEC anticipates key elements of modern MBSE platforms, including centralized data repositories, plug-in analytical modules, and integrated communication channels for distributed teams. Modern cloud-based MBSE platforms now execute this architecture at internet scale, enabling globally distributed design teams to collaborate on a single authoritative system model in real time — a capability that is essential for the international consortia increasingly characteristic of commercial and governmental space programs.

4. Regulatory Architecture and Legal Landscape

The regulatory framework governing reusable orbital launch vehicles has struggled to keep pace with operational reality. Under 14 C.F.R. Parts 400–460, the FAA's Office of Commercial Space Transportation licenses each launch and re-entry, with safety, risk, and financial responsibility requirements assessed at the program level. Each Starship test flight has required individual FAA launch licenses, and each has had multiple associated reviews — a process SpaceX publicly criticized as "repeatedly derailed by issues ranging from the frivolous to the patently absurd" in August 2024.^[22]

Environmental compliance has been a major complicating factor. Following the April 2023 first Starship integrated flight test — which caused substantial damage to the launch pad, scattered particulate matter as far as six miles from the site, and sparked a 3.5-acre fire on state park land — a coalition of environmental organizations filed suit in federal court in Washington, D.C., against the FAA for allegedly failing to conduct a full Environmental Impact Statement before issuing Starship's Part 450 launch license.^[23] SpaceX successfully moved to intervene as a co-defendant.^[24] The FAA subsequently completed a full EIS process, and in May 2025 authorized SpaceX to conduct up to 25 Starship launches per year from Starbase — a fivefold increase from the prior limit of five.^[25] A separate Department of the Air Force Record of Decision issued in December 2025 authorized up to 76 launches and 152 landings annually from Cape Canaveral Space Force Station, pending FAA completion of a supplemental airspace analysis.^[26]

The regulatory tension extends to enforcement. In 2024, the FAA proposed civil penalties against SpaceX related to alleged licensing and safety violations on two earlier launches, and the Texas Commission on Environmental Quality issued a separate enforcement action for Clean Water Act violations at Starbase.^[22] These proceedings highlight a fundamental systems engineering governance issue: the FAA's current licensing regime was designed for infrequent, individually inspected launches — not for a vehicle certified to fly dozens of times per year. The development of a risk-informed, flight-history-based certification framework analogous to those used in commercial aviation airworthiness standards is an urgent priority.

5. Trajectory Tools and Mission Analysis for Reusable Configurations

Mission analysis for reusable vehicles differs substantially from expendable trajectory optimization because the vehicle's mass properties, engine performance margins, and propellant reserves must simultaneously satisfy both the outbound mission requirements and the return-to-Earth recovery sequence. The Program to Optimize Simulated Trajectories (POST), long a workhorse of NASA's MSFC Advanced Concepts Office for ascent and reentry analysis, remains relevant in modern reusable vehicle development. However, the growing complexity of propellant reserve allocation, entry guidance, and precision landing requirements has driven development of more sophisticated multi-phase trajectory optimization tools.

For low-thrust applications — nuclear-electric propulsion, solar electric propulsion, and emerging in-space transportation architectures — the MSFC-managed Low Thrust Trajectory Tool suite, including ChebyTOP and VariTOP and newer codes like MALTO and Copernicus, provides the analytical foundation for interplanetary mission analysis. The goal of this suite, as documented in MSFC technical literature, is to bring state-of-the-art convergence reliability and user-friendliness to low-thrust trajectory analysis across all NASA centers. The emergence of reusable in-space transfer vehicles — depot-serviced orbital tugs capable of multiple round trips — extends these trajectory analysis requirements to include propellant replenishment planning, vehicle state estimation across multiple mission legs, and multi-body gravity assist optimization.

6. The Iterative Concurrent Engineering Imperative

The foundational systems engineering concept illustrated in the MSFC Advanced Concepts Office framework — where a preliminary design team develops low-fidelity architectural trades that are subsequently handed off to a detailed analysis team such as VIPA for higher-fidelity validation — remains valid in its essential logic. What has changed is the speed, data richness, and computational fidelity at which each tier operates, and the degree to which they must remain coupled throughout the vehicle's operational life rather than separating at a design freeze milestone.

SpaceX's iterative approach to Starship development — building and flying vehicles in rapid succession, accepting failures as data points, and incorporating lessons learned into the next vehicle batch — represents an extreme implementation of concurrent engineering that challenges classical systems engineering V-model doctrine. The ten Starship integrated flight tests conducted through October 2025 each incorporated design modifications from the previous test, compressing what would traditionally be years of analysis and ground testing into months of flight data collection.^[5] This approach produces extraordinary learning rates but raises legitimate questions about how verification evidence accumulates in a system that is continuously changing, and how design margins are established and tracked across a non-stationary vehicle configuration.

The aerospace industry's response to this challenge has been to invest heavily in MBSE's authoritative source-of-truth architecture, in which every design change is reflected in the system model and automatically propagates through requirements traceability, interface definitions, and verification cross-references. By employing MBSE, aerospace engineers can simulate and validate designs much earlier in the process, reducing both time and cost — and the success of reusable rocket component programs has been cited as a concrete demonstration of MBSE's power to optimize resource use and accelerate development cycles.^[27]

7. Open Research Challenges

Despite substantial progress, several systems engineering challenges for reusable orbital launch vehicles remain inadequately solved.

• Multi-flight certification methodology. The FAA's current licensing regime provides no standardized framework for certifying a reusable booster for its 20th or 30th flight based on accumulated flight history, TPS sensor data, and probabilistic structural models. Development of a risk-informed, flight-history-based certification standard — analogous to Federal Aviation Regulation Part 25 continuous airworthiness standards for transport category aircraft — is the most urgent regulatory systems engineering need in the industry.
• TPS autonomous inspection and repair. Current TPS inspection relies heavily on human technicians examining thousands of individual tiles or blanket sections between flights. Autonomous robotic inspection integrated with AI damage detection, digital twin updating, and predictive maintenance scheduling is essential to achieving the rapid turnaround rates that fully reusable vehicles require. Research into self-healing materials and hybrid active/passive TPS systems is ongoing but has not yet reached the manufacturing readiness levels required for operational deployment.^[11]
• MBSE–digital twin integration maturity. While the conceptual framework for combining MBSE with digital twins is well established in the literature, integrating DT development with MBSE throughout a complex system's lifecycle remains difficult in practice. DT development is highly system-specific and often requires additional effort that begins after initial system fielding — complicating its integration with MBSE, which is generally applied throughout the design lifecycle. The risk of creating a system-of-systems governance problem, in which the digital twin and the physical vehicle diverge in undocumented ways, demands formal model governance protocols that do not yet exist as industry standards.^[21]
• Ground systems and launch site capacity. Cape Canaveral's 50-year forward infrastructure plan, initiated in 2024, anticipates a major increase in launch cadence and landing operations — including port and transportation upgrades to support the new generation of vehicles.^[5] Ground processing system design — including propellant loading architectures, booster inspection facilities, and pad turnaround sequencing — is itself a complex systems engineering problem that receives less scholarly attention than vehicle design but is equally important to the economics and safety of reusable launch operations.

---

8. Conclusion

Reusable orbital launch vehicles have transitioned from aspiration to operational reality at a pace that has consistently outrun the maturation of supporting systems engineering methodologies. The classical tools of the trade — parametric sizing models, trajectory optimization codes, structural load analysis, cost and reliability assessment — remain relevant and necessary, but they are no longer sufficient. The multi-flight operational life of a reusable booster demands that systems engineers expand their analytical horizon from launch day to encompass the full lifecycle: from conceptual trade space development through high-flight-count operations, sustained by continuous structural health monitoring, probabilistic certification updates, and a digital twin synchronized to each vehicle's actual flight history.

Model-Based Systems Engineering, integrated with digital twin technology and anchored by a rigorous digital thread from design through operations, provides the methodological architecture required for this expanded scope. The regulatory framework must evolve in parallel, moving from per-launch licensing toward risk-informed continuous airworthiness certification grounded in vehicle health data. The organizations — governmental and commercial — that master this integrated systems engineering approach will define the architecture of human access to space for the next half-century.

Verified Sources & Formal Citations

References

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9. Le, V.T., Ha, N.S., and Goo, N.S. "Advanced sandwich structures for thermal protection systems in hypersonic vehicles: A review." Composites Part B: Engineering, vol. 226, p. 109301, December 2021. DOI: 10.1016/j.compositesb.2021.109301.
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11. Multiple authors. "Evolving Thermal Protection Systems: Reviewing Materials, Sensing, and Smart Solutions." AIAA Aviation Forum and ASCEND 2025 Conference Proceedings, Paper 6.2025-4066. Copyright © 2025, American Institute of Aeronautics and Astronautics.
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12. Columbia Accident Investigation Board. Report of the Columbia Accident Investigation Board, Vol. I. NASA and the Government Printing Office, August 2003. [As cited in ResearchGate review of SHM for reusable launch vehicles.]
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13. Huybrechts, S., et al. "Structural Health Monitoring and Risk Management of a Reusable Launch Vehicle." Journal of Spacecraft and Rockets, AIAA. DOI: 10.2514/1.A32156.
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15. Oler, J. "Seattle's Lessons for Rocket Reusability." Cited in: "Orbital Infrastructure: The Engineering Hurdles of Upper Stage Reusability." SatNews, February 19, 2026.
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16. Altium Resources. "Model-Based Systems Engineering in the Era of Digital Twins: A Paradigm Shift in Electronic Product Development." Altium.com, November 19, 2024; updated June 25, 2025.
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17. MachineCircuit. "Model-Based Systems Engineering (MBSE) Guide 2025." MachineCircuit.com, October 2, 2025. [Cites INCOSE Systems Engineering Handbook and NASA case studies.]
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18. NDIA Tennessee Valley Chapter. "2025 Model Based Systems Engineering Symposium." Event proceedings, May 21–22, 2025, Huntsville, AL.
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19. Madni, A.M., et al. "Digital Twin-enabled MBSE Testbed for Prototyping and Evaluating Aerospace Systems: Lessons Learned." 2021 IEEE Aerospace Conference, Big Sky, MT. DOI: 10.1109/AERO50100.2021. [Cited in MDPI 2025 review.]
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22. Reyes, O. "Elon Musk takes campaign against the regulatory state from labor to aviation." Legal Dive, September 27, 2024.
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24. CNBC Staff. "SpaceX set to join FAA to fight environmental lawsuit that could delay Starship work." CNBC, May 23, 2023.
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26. Department of the Air Force / Justia Regulation Tracker. "Notice of Record of Decision for the Environmental Impact Statement for SpaceX Starship-Super Heavy at Cape Canaveral Space Force Station, Florida." Federal Register Vol. 90, No. [date], FR Doc No. 2025-23314. December 18, 2025.
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27. Sheikh, A. "Unleashing the Power of MBSE, Digital Thread, and Digital Twin Technologies in Aerospace." LinkedIn Pulse, March 13, 2024.
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28. Alexander, R. "Space Vehicle Systems Analysis: MSFC Tools and Processes." Session Paper GT-SSEC.A.2, Systems Analysis and Systems Engineering Conference, NASA Marshall Space Flight Center, Advanced Concepts Office. [Foundational reference — source document for this review.]

 

Securing the Seabed:

SEABED TECHNOLOGY REVIEW

Telecommunications & Digital Infrastructure Intelligence

Security Supplement • March 2026

Infrastructure Security & Resilience

Physical Resilience, Geographic Redundancy, Island Breaks, and Cyber Threats in Pacific Submarine Cable Architecture

A companion analysis to the Honomoana deployment, examining the threat environment facing the 14,215-km transpacific cable from anchor drag and state-sponsored sabotage to SIGINT tapping — and the design choices that determine whether island intermediate nodes reduce or amplify risk.

 

Security & Infrastructure Correspondent

Analysis • March 10, 2026

■ BLUF — Bottom Line Up Front

The 14,215-km Honomoana transpacific trunk faces a layered threat environment encompassing three distinct risk categories: 

 

(1) unintentional physical damage from fishing gear and anchors — historically accounting for over 75% of annual faults globally — which poses the highest probability but lowest strategic consequence; 

 

(2) intentional state-sponsored sabotage, demonstrated by Chinese- and Russian-linked anchor-dragging incidents in the Baltic Sea (2024) and near Taiwan (2023–2025), representing lower probability but potentially high consequence in a gray-zone or conflict scenario; and 

 

(3) signals intelligence exploitation at cable landing stations or at mid-ocean repeater regeneration points, representing the highest intelligence-value attack vector and the primary driver of US national security conditions on FCC cable landing licenses. 

 

Regarding island intermediate breaks: Hawaii and French Polynesia landings in the Google South Pacific Connect architecture provide genuine resilience benefits through traffic rerouting flexibility and shortened repair staging distances — but each island landing also creates a new terrestrial attack surface and a cable approach zone exposed to shallower-water anchor and fishing risk. The Solomons, while strategically positioned as a future branching node, currently represent an unresolved geopolitical vulnerability given China's 2022 security treaty with Honiara. No single design eliminates all risk categories simultaneously; the South Pacific Connect ring topology represents the current best-practice engineering response, but the 200-fault-per-year global baseline confirms that outage probability over a 25-year cable life remains non-trivial.

I. The Fault Baseline: How Often Do Long Cables Break?

Before evaluating the specific threat posture of Honomoana, it is necessary to establish the statistical baseline against which any cable system must be measured. The International Cable Protection Committee (ICPC) reports approximately 100 to 200 cable faults per year on the global submarine telecommunications network — a rate that has remained broadly stable for more than a decade, despite the rapid growth in installed cable kilometers. A 2025 analysis by the ICPC cited by multiple sources confirms roughly 200 faults annually in 2025 alone across 597 active and under-construction cable systems.

The cause distribution is well-established and consistent across analytical sources. According to the Congressional Research Service's 2023 report on undersea cable protection, approximately 75% of cable breaks result from human activities — primarily fishing gear and ship anchors — with natural hazards (earthquakes, submarine landslides, turbidity currents) accounting for about 14% and equipment failure for roughly 6%. A 2024 Recorded Future (Insikt Group) analysis of 44 publicly reported cable damage events in 2024–2025 found that unknown causes accounted for 31% (many of which may have involved anchor drag with opaque attribution), anchor dragging for 25%, and seismic or natural phenomena for 16%.

For a 14,215-km cable with approximately 200 repeaters spaced at roughly 70-km intervals, the exposure surface is significant. Each repeater represents a potential equipment failure point, and the cable's geographic extent crosses multiple seabed environments of varying risk — shallow shelf zones near California and Australia where anchoring and fishing activity are concentrated, and deep abyssal plain in the central Pacific where the predominant risk is seismic or turbidity-current related. The design life expectancy is 25 years, during which industry benchmarks suggest a well-engineered transoceanic cable should require fewer than two ship repair operations attributable to submerged equipment failure alone — but external physical events are a separate matter entirely.

Global Cable Fault Statistics — Key Benchmarks

• ~100–200 faults/year globally (ICPC); ~200 reported in 2025
• 75%+ of breaks caused by human activity (fishing, anchoring)
• Fishing: ~50% of identified faults (ICPC)
• Anchor drag: ~25% of identified faults (2024–25 Insikt data)
• Seismic/natural: ~14–16%
• Equipment failure: ~6%
• Fewer than 100 cable repair vessels worldwide (global fleet); most are over 20 years old
• Repair staging for a mid-Pacific fault: typically 2–4 weeks from vessel dispatch to completion

II. The Physical Threat Environment Along the Honomoana Route

A. Shore Approaches and the Shallow-Water Vulnerability Window

The most statistically dangerous segments of any cable system are the shore approaches — the relatively shallow zones within the first 200 nautical miles of each coast, where shipping traffic, commercial fishing, and recreational and commercial anchor activity are concentrated. These areas are also, not coincidentally, where cables are most accessible for deliberate interference without the technical complexity required for deep-ocean operations. At Carlsbad, the cable terminates in a horizontal directional bore beneath the surf zone, emerging 3,000 feet offshore — a standard design intended to push the accessible cable end beyond the typical recreational anchor zone, though well within the commercial shipping lane environment offshore Southern California.

The Australian shore approaches at Torquay, Victoria, and Maroubra, New South Wales, face analogous risks. The Bass Strait — through which approaches to Melbourne must pass — is a notoriously active fishing ground. The SUBCO-Google shared landing station arrangement at these two sites is partly motivated by the efficiency of concentrating shore protection and monitoring at a single physical point, reducing the number of exposed cable approach corridors that must be actively managed.

B. Deep-Water Seismic and Turbidity Hazards

The central Pacific route of Honomoana traverses one of the geologically more benign portions of the Pacific seabed in terms of turbidity current risk — unlike the more active tectonic margins of the western Pacific or the earthquake-prone zones of the Southwest Pacific. However, the route does skirt the seismically active region around French Polynesia, and the branch segments to Tahiti Nui and Tahiti Iti are positioned in a zone where underwater volcanic activity has historically damaged regional cables. The 2022 Hunga-Tonga volcanic eruption destroyed Tonga's sole submarine cable, leaving the island's 100,000 residents in digital isolation for more than a month. The cable broke again two years later, underscoring the long-term vulnerability of systems transiting seismically active zones.

C. State-Sponsored Gray-Zone Anchor Drag

Baltic Sea Precedents: Anchor Drag as a Weapon

Between October 2023 and December 2024, nine separate submarine cable damage events were recorded in the Baltic Sea, in addition to damage to a gas pipeline and the ESTLINK 2 power cable. In four identified cases, ships with China- or Russia-linked ownership dragged anchors along the seabed for distances of up to 100 nautical miles. The Chinese vessel Yi Peng 3 was the subject of a weeks-long diplomatic stand-off after reportedly severing cables between Finland/Germany and Lithuania/Sweden. The Eagle S, a vessel of the Russian "shadow fleet" on route from Russia to Egypt, was suspected of dragging an anchor that severed Estlink 2 on Christmas Day 2024. In response, NATO launched Operation Baltic Sentry in January 2025. No state actor has been successfully prosecuted for a confirmed cable sabotage event under current international law.

The most operationally significant threat evolution in the past 24 months is the demonstrated use of commercial vessels — operating under the cover of routine maritime traffic — to conduct anchor-drag attacks on submarine cables as a gray-zone tactic. The pattern is now well-documented in the Baltic Sea, where a 2025 Insikt Group analysis of 44 cable damage events in 2024–2025 attributed at least four to Chinese- or Russia-linked vessels operating with "opaque ownership structures" or "suspicious maneuvers near damaged cables." The technique is technically simple, requires no specialized equipment, and is designed to maintain plausible deniability because UNCLOS Article 113 assigns jurisdiction for cable damage offenses to the flag state of the vessel — an enforcement gap that has not been closed by any binding international agreement.

The Pacific threat environment differs from the Baltic in important structural respects. The Baltic is a semi-enclosed sea with dense shipping traffic and relatively shallow water throughout, making anchor-drag attacks easy to execute and difficult to attribute. The transpacific route traverses vast areas of open ocean at depths of 4,000–6,000 meters — far below the operational range of any ship's anchor under normal conditions. The highest-risk segments remain the shore approaches and shallow shelf zones, which mirrors the Baltic experience. The broader Pacific region has seen multiple cable incidents around Taiwan — five in 2024–2025 alone, according to Insikt data — with Chinese vessels operating in the area during at least some of these events.

For Honomoana specifically, the primary gray-zone exposure points are: (1) the Carlsbad shore approach, in proximity to one of the world's busiest commercial shipping corridors; (2) the approaches to the Australian landings in Victoria and New South Wales, transiting Bass Strait and the Australian continental shelf; and (3) the French Polynesia branch terminations, where the cable enters shallow coastal water around Tahiti. The deep abyssal trunk is not immune to sophisticated state-actor interference, but the technical challenge is substantially greater.

III. The Island Break Question: Resilience Asset or Vulnerability Node?

The question of whether intermediate island landings — in Hawaii, French Polynesia, Fiji, or the Solomon Islands — enhance or complicate the security and resilience of a long transpacific cable requires disaggregating two distinct functions that such breaks serve: traffic restoration and repair staging. The answer differs materially depending on which function is being evaluated, and further depends on the geopolitical character of the island in question.

A. Traffic Restoration: The Case for Island Breaks

An island break converts what would otherwise be a single point of failure on a trunk cable into a set of separate segments with independent failure modes. If the eastern segment of a cable (US to Hawaii) is severed, traffic can continue to flow on the western segment (Hawaii to Australia) — provided the island has sufficient onward connectivity to alternative systems to carry the diverted load. This is the function that Hawaii performs in the Tabua system: Google's April 2024 announcement extended the Tabua cable to include an Oahu segment, with Google's director of Asia Pacific network planning explicitly describing Hawaii as becoming "a key digital hub in the Pacific." Hawaii's lieutenant governor noted that two of the state's three existing transpacific fiber links were approaching end of operational life, making the Tabua Hawaii extension a resilience investment as much as a commercial one.

French Polynesia's role in the Honomoana architecture serves a similar function. The two Tahiti branch segments connect to a seabed branching unit on the main transpacific trunk, and the South Pacific Connect ring — connecting the Honomoana and Tabua trunks via an interlink cable between Fiji and French Polynesia — creates a closed loop. In a fault scenario affecting the US-side portion of Honomoana, traffic can in principle be rerouted eastward through French Polynesia and Fiji on the Tabua path, and vice versa. Google Cloud VP Brian Quigley described this explicitly as "one of the first projects of its kind in the Pacific, providing the ability to bring redundant international connectivity to a region that is susceptible to natural disasters."

The Tabua system provides a further resilience design feature that deserves technical attention: it terminates at two physically separate landing points on the Fijian island of Viti Levu — on both the east and west sides of the island. According to Submarine Networks documentation, this dual-island landing "provides path diversity, redundancy in island connectivity in case of a single branch failure, and greater resiliency by supplying the cable with single end power source capability." This is sophisticated resilience engineering that directly addresses the single-point failure risk that made the Tonga incident so severe.

B. The Solomons: Strategic Asset or Geopolitical Liability?

⚠ Geopolitical Risk Alert: Solomon Islands

The 2022 security treaty between China and the Solomon Islands government remains the most significant unresolved geopolitical complication for any cable routing that would transit or terminate in Honiara. Australia's decision in 2019 to fund the Coral Sea Cable System (CS2) connecting Sydney to PNG and the Solomons was explicitly motivated by preventing a Huawei-built cable from landing in Australian territory. Any future cable routing through the Solomons must account for the possibility that cable landing station infrastructure could be subject to access agreements with, or pressure from, Chinese security services under the 2022 treaty framework.

The Solomon Islands occupy a genuinely strategic geographic position in the Pacific cable network — situated roughly mid-path between Sydney and Guam, they could serve as a natural transit node in a more distributed "mesh" architecture of the kind proposed by University of Auckland researchers writing for APNIC. However, the security calculus has become considerably more complex since 2022.

The Australian government's track record on this issue is instructive. When the Asian Development Bank originally offered to finance a cable connecting the Solomons using Huawei Marine Networks, Australia objected and funded the CS2 itself — a AU$200 million project connecting Sydney to Port Moresby and Honiara, completed in December 2019. The stated rationale was that Australia was "unwilling to have Chinese equipment connected to its infrastructure." The US Trade and Development Agency's (USTDA) proposed Central Pacific Cable — a feasibility study currently underway — would include the Solomons in a mesh connecting American Samoa, Cook Islands, Fiji, Guam, Kiribati, Marshall Islands, Micronesia, Nauru, Papua New Guinea, Samoa, Solomon Islands, Tuvalu, Vanuatu, and Wallis and Futuna. Whether that project can proceed with the Solomons included, given the current security treaty with Beijing, is an open question that USTDA has not publicly resolved.

The general principle that emerges from the Solomons example is that the security value of an island intermediate node is inseparable from the security governance of the landing station infrastructure at that node. A landing station in a jurisdiction with robust rule of law, allied security relationships, and effective exclusion of adversary access to physical plant is a genuine resilience asset. A landing station in a jurisdiction where an adversary power has negotiated security access rights is potentially the opposite.

C. Repair Staging: The Practical Value of Intermediate Nodes

The global cable repair fleet consists of fewer than 100 vessels worldwide, most of them aging — the majority over 20 years old, and only one major Pacific repair vessel (KDDI Cable Infinity) built after 2010. A mid-ocean fault on the Honomoana trunk — at, say, the midpoint between California and French Polynesia — would require a repair ship to travel approximately 3,500 km from the nearest port with repair capabilities. The Japan-based Yokohama Zone maintenance arrangement, established under a 1997 multinational agreement, provides two standby vessels equipped with ROVs and spare parts for rapid response across the Asia-Pacific region. However, "rapid" in this context means days to weeks, not hours.

An island intermediate node reduces the maximum repair-mobilization distance by providing a potential forward staging base for cable repair equipment and personnel. Hawaii is the most valuable such node for the US-side of the transpacific route: it is a major US military logistics base with existing port infrastructure capable of supporting cable ship operations, and Google's decision to extend the Tabua cable to Oahu makes Hawaii an active node in the South Pacific Connect architecture rather than a simple geographic waypoint.

French Polynesia provides analogous staging value for the central Pacific segment of Honomoana. Papeete, the capital of French Polynesia, has deep-water port facilities and is already an established supply point for Pacific maritime operations. The existing OPT cable infrastructure at French Polynesia — including the Honotua (2010) and Manatua (2020) systems — means that local technical expertise in cable operations already exists in-country.

IV. The Cybersecurity Dimension: From Tempora to Today

A. Physical Tapping at Landing Stations

The cybersecurity threat to submarine cables operates at a fundamentally different layer from physical sabotage. While physical attacks seek to deny service, signals intelligence (SIGINT) exploitation seeks to access the content and metadata of traffic flowing through the cable — ideally without the cable owner's knowledge and without causing any service disruption that would alert operators to the presence of the tap.

The most thoroughly documented mechanism for cable SIGINT exploitation is the installation of optical splitters or "intercept probes" at cable landing stations, with the cooperation (voluntary or legally compelled) of the cable operator or landing station host. This is the technique described in detail in the Snowden disclosures of 2013, which revealed that GCHQ's TEMPORA program was tapping 18 or more international submarine cables landing in the United Kingdom, sharing the collected data with the NSA under the INCENSER program. The method involved inserting a device that extracted a small percentage of the optical signal — typically via a fiber splitter — from each fiber pair in the cable, feeding the extracted signal to a processing center for bulk collection and filtering. GCHQ worked with Verizon Business, BT, Vodafone, and other carriers as "intercept partners" for this purpose.

The Snowden disclosures further confirmed that the NSA operated analogous facilities at landing stations in the United States, and that the USS Jimmy Carter submarine had been modified to access cables at repeater regeneration points in locations "where stations that receive and transmit the communications are on foreign soil or otherwise inaccessible." Cold War precedent for this approach dates to Operation Ivy Bells, a CIA/NSA/Navy program running from 1971 that successfully tapped Soviet communications cables in the Sea of Okhotsk — until NSA analyst Ronald Pelton sold the program's details to Soviet intelligence in 1980.

The security implication for Honomoana is direct: as a privately owned system with its landing station in US territory at Carlsbad, traffic transiting the cable is subject to US lawful intercept requirements under CALEA, Section 702 of the FISA Amendments Act, and the conditions of the National Security Agreement between Starfish, Google, and DHS/DOJ/DOD. The NSA's requirement is for access to be technically enabled, not necessarily that it be continuously exercised. Google's NSA compliance obligations are separate from the question of whether a foreign adversary power might attempt to tap the cable at a non-US landing station or at a mid-ocean repeater node.

B. The Adversary Tapping Threat: State Actors and the Deep-Ocean Challenge

The threat of adversary tapping — by a foreign intelligence service without the cable owner's knowledge — differs technically from the landing-station interception model. At a deep-ocean repeater node on a cable like Honomoana, the technical challenge of passive optical tapping without disturbing the fiber is significant but not insurmountable for a well-resourced state actor. Reports, denied by the US government, have consistently attributed to the USS Jimmy Carter (and its predecessor systems) a capability for exactly this kind of deep-ocean cable access. Russia is independently assessed to possess this capability through its Autonomous Uninhabited Underwater Vehicle (AGS) program — described in open-source analysis as small, nuclear-powered submersibles capable of tapping fiber cables in deep water. These vehicles have been observed operating in proximity to transatlantic cables, including in the North Atlantic near Iceland and the UK–Faeroes gap.

The Princeton Journal of Public and International Affairs notes that "espionage against submarine cables accesses transmitted data, usually without damage or notable disruption" and that "since espionage using submarine cables is internationally legal in the high seas and within a coastal state's own waters, spying operations against cables in these areas are limited only by a state's morals and technology." This legal vacuum is a structural feature of the international law framework governing submarine cables — UNCLOS Article 113 criminalizes intentional cable damage but says nothing about surveillance tapping that leaves the cable physically intact.

C. Remote Network Management: The Cyber Attack Surface

A third, distinct cybersecurity threat vector has emerged from the increasing use of internet-connected remote management systems for submarine cable network monitoring and control. The Congressional Research Service's 2023 analysis of undersea cable protection notes that "more companies are using remote management systems for submarine cable networks — tools to remotely monitor and control cable systems over the Internet — which are cost-compelling because they virtualize and possibly automate the monitoring of cable functionality. However, they may also create new risks and opportunities for cyberattack."

This is a generic IT/OT convergence problem with specific consequences for cable systems: a successful intrusion into the supervisory and control network of a cable system could, in principle, enable an adversary to disrupt service, degrade specific traffic streams, or surveil operational parameters that would reveal traffic volumes and routing patterns. The Insikt Group 2025 threat assessment states that "geopolitical, physical, and cyber threats" to submarine cables "have converged," and that the threat environment for the overall cable ecosystem "has very likely escalated" relative to the prior assessment period. The FCC's 2024 Cable NPRM — the first comprehensive rule review since 2001 — was prompted in part by the Salt Typhoon intrusion into at least eight US communications companies, attributed to Chinese state-sponsored actors, which demonstrated the degree to which adversary cyber operations against US telecommunications infrastructure had matured.

"The scale and exposure of undersea infrastructure also make it an easy target for saboteurs operating in the gray zone of 'deniable attacks short of war.'"
— Center for Strategic and International Studies, 2024

V. The Repeater Architecture of a 14,215-km Cable: Security Implications

Honomoana's transpacific trunk at 14,215 km will require approximately 200 optical amplifier repeaters, based on the industry-standard spacing of 50–80 km (centered on ~70 km) for high-capacity transoceanic cables. Each repeater is a pressure-sealed unit containing erbium-doped fiber amplifiers (EDFAs), which amplify the optical signal without optical-to-electrical conversion — a significant improvement over older regenerator-based designs. Power is supplied from both shore ends of the cable via a high-voltage DC conductor running within the cable, typically ±7.5 kV per shore end (±15 kV total potential difference), sufficient to power 100 repeaters from each end with the midpoint at virtual earth.

From a security standpoint, the repeater architecture has several implications. First, each repeater housing represents a potential physical access point for a tapping device; the sealed pressure vessel is designed to prevent ocean ingress, not to prevent tampered access by a technically sophisticated actor deploying a deep-submersible. Second, the power conductor that feeds the repeaters is itself a source of intelligence: monitoring the current draw on the power feed reveals information about repeater operational status, and anomalies in power consumption patterns can indicate faults or tampering. Third, the supervisory channel embedded in the optical overhead of the cable — used for order-wire communication and equipment status monitoring between shore stations — is a potential attack vector if the cable management network is compromised.

On a 14,215-km system, the "midpoint earth" zone — where the voltage of the power conductor passes through zero — is approximately 7,100 km from each shore terminal, roughly in the central Pacific between French Polynesia and Southern California. This zone is of particular interest for physical tapping operations because it is the point of minimum voltage on the power conductor, reducing the electrical hazard to any device being physically attached to the cable housing.

VI. The South Pacific Connect Ring: Engineering Response to a Layered Threat

Assessed against the threat taxonomy developed in the preceding sections, the South Pacific Connect ring topology — Honomoana plus Tabua plus the Fiji–French Polynesia interlink — represents a reasonably well-engineered resilience response to the physical and geographic threat categories. The ring creates two independent transpacific paths from California to Australia (one via French Polynesia, one via Fiji), with a southern interlink that allows traffic to transit around a failure on either trunk. Multiple Australian landings (two for Honomoana, two for Tabua, with the SUBCO SMAP system providing additional domestic diversity) mean that no single cable cut at an Australian shore approach can isolate the continent.

What the ring topology does not address is the cybersecurity threat. Two cables, both owned by the same entity (Starfish/Google), both subject to the same NSA and FCC oversight framework, and both landing at facilities managed by the same operator, do not provide diversity against a compromise of the cable management network or the landing station intercept architecture. True cyber resilience requires ownership diversity — traffic on Honomoana is most safely protected when the alternative path (Southern Cross, Hawaiki, or a future system) is operated under a different ownership and management structure, with independent security controls.

The APNIC research community has for several years advocated a more ambitious architectural vision — a distributed Pacific mesh in which island nations serve as transit and peering nodes rather than dead-end spur recipients, creating multiple short hops with many independent operators rather than a small number of long transoceanic trunks dominated by hyperscalers. University of Auckland researcher Dr. Ulrich Speidel has argued that "islands serve as natural transit and peering venues" and that a mesh architecture would make "monolithic 12,000+ km transpacific cables less crucial." That vision would take an estimated $1 billion in coordinated multilateral investment to achieve and would require a level of Pacific island institutional capacity that does not yet exist. The South Pacific Connect initiative, with its pre-positioned branching units and US-Australia joint funding of $65 million for Pacific Island connections, is a partial step in this direction — but the mesh remains aspirational rather than operational.

Honomoana Threat Matrix — Physical and Cyber Vectors

Threat Vector	Probability	Impact	Applicable Segments	Mitigation Status
Fishing gear / accidental anchor (unintentional)	HIGH	MODERATE (outage, recoverable)	Shore approaches CA, AU; shelf zones	Cable burial to 1m depth; monitoring; repair fleet
State-sponsored anchor drag (gray-zone)	MODERATE	HIGH (targeted outage + attribution problem)	Shore approaches; shelf zones; potentially near French Polynesia	Ring topology for rerouting; monitoring; no enforceable international legal remedy
Seismic event / turbidity current	LOW–MOD	HIGH if seabed route through active zone	French Polynesia branches; seismically active shallow zones	Route selection avoids highest-risk zones; ring rerouting
Landing station intercept (SIGINT)	HIGH (US lawful; adversary: MODERATE)	Data access without outage	Carlsbad, AU landing stations; potential adversary interest at French Polynesia	NSA/FCC National Security Agreement (US); physical security at landing stations
Deep-ocean repeater tapping (state actor)	LOW (technically demanding)	HIGH (no outage, deniable, sustained access)	Central Pacific trunk; midpoint earth zone (~7,100km from CA)	No publicly disclosed technical countermeasure; encryption of traffic provides partial protection
Remote management network cyberattack	MODERATE	MODERATE–HIGH	Network-wide (landing station management systems)	FCC CALEA compliance; post-Salt Typhoon FCC review (2024 Cable NPRM)
Adversary landing at island node (Solomon Islands scenario)	LOW for Honomoana (no Solomons landing planned)	HIGH if materialized	N/A for current Honomoana design; relevant to future mesh expansion	US/Australia policy of denying Chinese-built systems at allied landing stations
Repeater power feed attack	LOW	HIGH (could disable hundreds of km of cable)	Shore power terminals at Carlsbad and Australian landings	Physical security at cable stations; redundant power feed from both ends

VII. The Encryption Question and the SMART Cable Opportunity

A frequently misunderstood aspect of cable security is the role of encryption. Fiber-optic cables transmit photons, not encryption — the security of traffic flowing through a cable depends entirely on whether the applications and protocols generating that traffic apply end-to-end encryption. A successful physical tap at a landing station or a deep-ocean repeater node will capture whatever optical signals are present in the fiber; if those signals carry encrypted traffic (TLS 1.3, IPSec, or application-layer encryption), the captured data is of limited intelligence value for content analysis, though metadata — source, destination, volume, timing — remains accessible at the physical layer regardless of encryption. Google encrypts traffic traversing its own network infrastructure as a matter of policy, which provides meaningful protection against content-level exploitation; it does not protect against traffic analysis.

A separate technological dimension with both scientific and security implications is the emerging SMART cable concept — Science Monitoring And Reliable Telecommunications — which integrates temperature, pressure, and seismic sensors into repeater housings. As noted by Scripps Institution geophysicist Mark Zumberge in the context of the Carlsbad landing, submarine cables are increasingly recognized as distributed sensor platforms capable of detecting earthquakes, ocean temperature changes, and acoustic signatures including marine mammal activity. The SMART cable concept, actively promoted by the UN Joint Task Force on SMART cables and championed by University of Hawaii researcher Bruce Howe, would convert every repeater node into a seismic and oceanographic monitoring station. From a security standpoint, SMART sensors that detect seismic anomalies can also detect the acoustic signatures of unusual underwater vehicle activity in the vicinity of a cable — providing an early-warning capability against physical tapping operations that has no equivalent in current passive cable monitoring systems.

"There is a movement led by Bruce Howe at the University of Hawaii to convince cable companies to add sensors to their cables for scientific purposes… Earth, ocean, and biological sciences are beginning to make significant gains because we've learned how to detect earthquakes, temperature changes, whale sounds, and all sorts of things remotely using the cables."
— Mark Zumberge, Scripps Institution of Oceanography

VIII. Assessment: Is the Current Architecture Adequate?

The South Pacific Connect architecture as designed — Honomoana, Tabua, the Fiji–French Polynesia interlink, and their integration with the Australia Connect program — represents a substantial improvement over the pre-2023 US-Australia cable environment, which consisted of the aging Southern Cross/NEXT and Hawaiki systems with limited redundancy and a single dominant US landing cluster in Los Angeles and the Pacific Northwest. The addition of a San Diego County landing at Carlsbad, physically diverse from existing Southern California systems, is a meaningful geographic diversification of the US shore approach.

The ring topology that Google has engineered into the South Pacific Connect initiative directly addresses the leading cause of significant outages: segment-level physical failures that previously had no alternate path. The pre-positioned branching units for future Pacific Island connectivity add resilience for the regional network even where the branching units are not yet activated. The dual Fiji landings on Tabua represent best-practice resilience design for island intermediate nodes.

What the current architecture does not fully address is the repair capacity deficit. With fewer than 100 repair vessels globally, most aging, and with the China-linked SBSS company dominating the regional maintenance market while being assessed as willing to delay operations in strategically sensitive areas, the time-to-repair following a major trunk fault remains a strategic vulnerability. The US and Japan have been pushing to diversify repair fleet ownership and strengthen domestic cable-laying capabilities — but this is a multi-year industrial base investment, not a near-term solution.

The cyber threat posture is adequate for the current threat environment against commercial-grade adversaries, but the NSA/GCHQ-level SIGINT capability demonstrated in the Snowden disclosures — and the Russian deep-ocean tapping capability assessed to exist — are not addressed by ring topology, redundant landings, or FCC national security conditions. The ultimate protection against content-level exploitation is end-to-end encryption by the applications and users generating the traffic, combined with robust traffic analysis countermeasures at the network layer. Google's own infrastructure encryption practice is a meaningful partial control; it does not protect third-party traffic transiting the cable under IRU or capacity lease arrangements.

The Solomon Islands remain an unresolved variable. They are not in the current Honomoana or Tabua routing, and the Coral Sea Cable System (CS2) connecting them to Sydney is Australian government-funded and managed — ensuring that the most sensitive link in their connectivity chain remains under allied control. Any future expansion of the Pacific mesh to include the Solomons as an active transit node would require either a resolution of the current China security treaty or a technically isolated connectivity arrangement that prevents Chinese access to the landing station infrastructure. Neither condition is currently satisfied.

Sidebar: Cable Laying Contracting

Google in bed with Chinese contractors/partners

The most significant case is not a Chinese contractor per se, but a Chinese co-owner — the Pacific Light Cable Network (PLCN), announced 2016. The PLCN cable system was jointly built and owned by Google, Meta, and PLDC (Pacific Light Data Communication), a Hong Kong company. PLDC owned four of the six fiber pairs in the system. Submarine Networks PLDC was acquired by Dr. Peng Telecom & Media Group in late 2017 Submarine Networks — a Beijing-based broadband provider with close Huawei ties — which triggered US alarm bells. Team Telecom urged the FCC to block the Hong Kong connection, citing the risk that the cable's Hong Kong landing station could "expose US communications traffic to collection by the PRC." Quartz

The resolution was telling: Google and Meta withdrew the original application and refiled, reconfiguring PLCN to connect the US only to Taiwan and the Philippines, excluding Hong Kong entirely. The two NSAs prohibit the applicants from allowing PLDC access to the cable and from using the disconnected Hong Kong segment. Submarine Networks

The contractor intelligence problem — survey data

Access to geographical data is the more subtle and underappreciated risk, and it goes well beyond just the laying operation itself. A submarine cable project generates multiple categories of intelligence-sensitive data:

The pre-lay route survey is particularly consequential. Prior to installation, the survey contractor provides the installer with integrated geophysical and geotechnical data — including bathymetric charts, seabed feature charts, and geological charts — to finalize the installation plan and procedures. Hydro International This data covers a 500m–1,000m corridor along the full cable route at multibeam sonar resolution — essentially a detailed classified-quality bathymetric strip chart across the entire Pacific floor along that specific track. For a 14,215-km cable like Honomoana, that's a comprehensive seabed intelligence product of obvious military value — submarine transit corridors, seamount positions, sediment type, and existing cable locations are all captured.

According to the DHS/ODNI Analytic Exchange Program, cables that lie on the seabed are "somewhat protected because their exact location is not publicly disclosed." Congress.gov A contractor who laid the cable knows the exact location — every waypoint, every burial depth, every course alteration. That Route Position List (RPL) is among the most sensitive technical documents the project produces.

The industry structure problem

The global cable market is dominated by four manufacturers and installers: SubCom (US), Alcatel Submarine Networks (France), NEC (Japan), and HMN Technologies (China, formerly Huawei Marine). In 2021, the three Western firms collectively held 87% market share, with HMN holding about 11%. Center for Strategic and International Studies But HMN's actual footprint on already-installed cable is larger than that current share suggests — between Huawei Marine and HMN Tech, the two entities have participated in at least 40 international projects, helping lay 94,000 km of cable Nikkei Asia, much of it before the US crackdown intensified.

For sensitive US projects, Washington now works only with SubCom, according to five industry sources. SubCom now works almost exclusively for the US military and large US tech firms. Marine Technology News The practical implication: HMN's cost advantage — reportedly 20–30% cheaper than allied competitors University of Washington — made it attractive to commercial operators globally for years, meaning a large portion of the existing Pacific cable network was built by what is now a Chinese state-linked entity with access to the corresponding survey data.

The South China Sea access-denial dimension

There's a reciprocal dimension worth flagging. The last submarine cable laid in the South China Sea by a non-Chinese vendor was the Asia Direct Cable, which applied for a permit in 2019. Since then, no publicly available information indicates that any project accepting non-Chinese EPC contractors has been granted approval to lay cables in the South China Sea. Springer China has effectively imposed a Chinese-contractor-only requirement in its claimed waters — which means Western cable operators transiting the South China Sea must use HMN or accept the route denial. Beijing is acquiring the survey data for all cables through its maritime territory while denying Western contractors equivalent access to generate survey data in Chinese-claimed waters. This is an asymmetric intelligence arrangement.

Where Honomoana stands

Honomoana routes through open Pacific — not the South China Sea — and SubCom is the contractor for sensitive US-connected projects Marine Technology News, so the current cable should use a Western EPC. The Honomoana FCC filing identifies Starfish Infrastructure (Google) as owner and the national security agreement conditions require compliance with DHS/DOJ/DOD requirements. However, the Carlsbad uncrewed survey vessel deployed in early February 2026 was described in the San Diego Union-Tribune reporting as part of a marine survey operation — worth noting that survey vessel ownership and contracting chain on the Australian end of the project has not been publicly detailed to the same degree as the US-side permits.

The residual problem

The deepest unresolved issue is the legacy. HMN/Huawei Marine built or upgraded cables that are still in service and carrying traffic. Those operators have the survey data, the RPLs, the repeater placement coordinates, and in some cases participated in the cable management network design. China held up at least one cable project for several months in its territorial waters, with a former US submarine officer noting that "China is attempting to exert more control over undersea activities in its region, in part to prevent US surveillance systems from being installed as part of undersea cable deployment." Data Center Dynamics The surveillance concern runs both ways — and the years when cost optimization drove Google, Meta, and others toward Chinese-adjacent partners left a bathymetric and infrastructure intelligence legacy that forward-looking contractor restrictions cannot retroactively address.

Sidebar: Local Security in Carlsbad

The physical sabotage narrative gets all the press — Baltic anchor drags, Red Sea cuts — but for a US-terminus cable in the current intelligence environment, the more consequential threat is probably passive exploitation at the shore end, not destruction of it. The Carlsbad configuration is particularly interesting from that angle.

The geometry of the intercept opportunity

The directional bore brings the cable from ~3,000 feet offshore into a 100 sq ft vault on State Parks land, then 4.3 miles inland to the Cosmos Court SLTE building. That vault-to-building conduit segment is where the cable transitions from a sealed, pressurized, high-voltage ocean system into an accessible terrestrial fiber run. At that transition point the cable is no longer armored ocean cable — it's a fiber conduit in a standard telecommunications trench. The optical splitter technique used in the GCHQ TEMPORA program (inserting a device that extracts a small percentage of the optical signal from each fiber pair) is much more practical to execute on a terrestrial conduit than on an armored repeater housing at 4,000-meter depth. The physics are identical — a fiber bend or a fused coupler tapping a few percent of the photon flux — but the access difficulty is orders of magnitude lower.

What the Snowden architecture tells us about the Carlsbad design

The NSA/GCHQ intercept model documented in the Snowden disclosures operated at landing stations with the cooperation of the cable operator or its host facility owner. At Carlsbad, there are actually three entities with physical access to different segments of the cable path: the State Parks Department (vault site), Vero Networks (conduit operator along Palomar Airport Road), and Elkhorn Enterprises/Google (Cosmos Court building). The national security agreement between Starfish/Google and DHS/DOJ/DOD will almost certainly include a lawful intercept architecture requirement — meaning the technical capability for NSA access is built into the design at Cosmos Court, per established CALEA and FISA Section 702 practice. That's the authorized side of the tapping equation.

The unauthorized side is the more interesting security question. The conduit along Palomar Airport Road runs through multiple utility corridor junctions where a sophisticated actor could access it without touching the vault or the Cosmos Court building at all. Unlike those two endpoints — which will have physical security controls imposed by the NSA agreement — the intermediate conduit is protected at whatever standard Vero Networks applies to a commercial fiber installation in a public right-of-way. That is typically a locked vault every few hundred meters and a buried conduit with no real-time tamper detection between vaults.

The traffic analysis value even without content decryption

Content decryption is not actually necessary for the most valuable intelligence product at this point in the network. At the Carlsbad landing, before traffic is disaggregated across Google's internal network, the cable carries the full aggregate load of all traffic on the fiber pairs — source and destination metadata, traffic volume patterns, protocol signatures, timing correlations. Even against encrypted traffic, a passive optical tap at this point yields:

• Which data centers at each end are actively communicating and at what volume
• Traffic burst patterns that reveal operational tempo for Google's Australian facilities
• Protocol signatures distinguishing bulk data transfer from interactive communications
• Potential correlation with signals collected at the Australian end to perform traffic analysis across the full path

For a state actor that has already placed intercept capability at the Maroubra or Torquay landing stations on the Australian end — or that can access traffic traversing Australian networks under Five Eyes arrangements — the Carlsbad tap completes a bilateral intercept picture. Espionage and sabotage operations may also be used in concert — the classic example being Britain's WWI operation that severed Germany's cables and then tapped the one remaining route to collect the Zimmermann telegram.

The specific vulnerability of the Cosmos Court facility

The SLTE building at Cosmos Court is where the most sensitive intercept opportunity exists, because that is where the optical signals are terminated and converted to electrical — the point at which traffic is most accessible without specialized optical equipment. Landing stations house network management equipment and power feeds, making them more accessible to threat actors. The use of remote network management systems creates another vulnerability that state-sponsored adversaries, ransomware groups, and other threat actors are likely to exploit.

A cyber intrusion into the network management system at Cosmos Court — rather than a physical tap on the conduit — could achieve several objectives simultaneously: passive monitoring of cable health telemetry (which reveals traffic loading patterns), potential manipulation of routing decisions, and access to the supervisory channel that runs through the cable's optical overhead between the US and Australian shore ends. Nokia's introduction of submarine cable terminal equipment had failed to clearly show the systems were not vulnerable to the attacks used in the Stuxnet operation against Iran — a reminder that the SLTE itself is an embedded system that may carry legacy vulnerabilities no different in character from the industrial control systems that Stuxnet targeted.

The irony of the NSA compliance architecture

The national security agreement conditions on Honomoana require Google to build in lawful intercept capability for US intelligence agencies. This is standard practice and entirely expected. The irony is that the technical implementation of that capability — the optical splitter or equivalent device installed at Cosmos Court to give NSA access — is itself an attack surface. If a foreign adversary can access the intercept facility rather than the cable itself, they obtain both the collected traffic and potentially the collection architecture. The Room 641A facility that AT&T operated in San Francisco for NSA upstream collection is the canonical public example: a fiber-splitting room that, if physically accessed or cyber-compromised, yields both the traffic and knowledge of what is being collected and how.

What adequate mitigation would look like

The NSA-conditioned licensing requirements will address the Cosmos Court facility directly — SCIF-equivalent physical security, access logging, cyber hardening of management systems. The gap that is harder to close is the intermediate conduit. Best practice for high-value cable backhaul in this threat environment would include distributed fiber sensing along the conduit (optical time-domain reflectometry monitoring that detects bending, tapping, or physical intrusion at any point), encrypted optical transport between the vault and the SLTE building so that any tap on the conduit captures ciphertext rather than plaintext optical signals, and regular physical inspection of all conduit access points. Whether Vero Networks — a commercial fiber operator — is required to implement those standards as a condition of its right-of-way permit is not clear from the public record. That gap in the chain of custody between ocean and SLTE building is the most plausible exploitation vector for a sophisticated actor who wants access without triggering the security controls at either endpoint.

 Verified Sources and Formal Citations

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This analysis is prepared for educational and professional reference. SIGINT program descriptions are sourced from publicly available Snowden disclosure reporting; no classified information is referenced or implied. © 2026 Seabed Technology Review.