Over the past couple years, undersea cables from the Baltic Sea to the Pacific Ocean have been severed in apparent acts of sabotage. Now a NATO-backed project has shown how to quickly re-establish the most critical communications using satellites.
The first demonstration of the $2.5 million project – short for Hybrid Space-submarine Architecture Ensuring Infosec of Telecommunications – took place in Sweden on 16 January. This test simulated how software can swiftly match outgoing data communications with available satellite internet providers, such as SpaceX’s Starlink and Viasat.
“Our goal is to route those data packets to whatever satellite communication capability is actually available in the market, and then assume that something is better than nothing,” says at Cornell University in New York.
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Even the fastest satellite internet can only achieve about 10 gigabits per second, compared with hundreds of terabits per second for undersea data cables. But the slower satellite speeds can still accommodate the most crucial communications – such as military data, financial transactions and the signals used to synchronise electric grids – that would be prioritised in an emergency, says Falco.
Rerouting traffic could help counter a recent spate of ships cutting undersea cables by dragging their anchors along the seafloor. In October 2023, a Chinese-registered vessel named damaged two undersea data cables and a gas pipeline in the Baltic Sea. That is the first known incident, but others followed: in November 2024, another Chinese-registered ship severed data cables in the Baltic Sea, and in December 2024 an undersea power cable was cut by an oil tanker named , which belongs to a shadow fleet carrying contraband oil for Russia.
“For NATO, protecting critical infrastructures, including undersea infrastructures, is essential to security and defence,” says a NATO spokesperson.
The HEIST demonstration coincides with NATO announcing a new “” initiative that will deploy more warships, aircraft and even a swarm of naval drones to patrol the Baltic Sea and protect against further such sabotage attempts.
But undersea cable disruptions are also occurring beyond the Baltic. In March 2024, three undersea data cables in the Red Sea were accidentally by the anchor of a UK-owned commercial vessel named the Rubymar – it started drifting after being struck by a missile fired by Yemen’s Houthi faction. And earlier this month, Taiwan’s coast guard began a Chinese-owned ship named Shunxing 39 that is suspected of damaging the Trans-Pacific Express Cable connecting China, Taiwan, South Korea, Japan and the US.
Backup options such as HEIST can signal resilience to anyone who may be tempted to sabotage undersea data cables, says at the Atlantic Council, a think tank based in Washington DC. But then the next obvious step would be for potential adversaries to go after the backup systems too.
“Satellites are good as a backup option, but they are expensive, and they too will become the subject of sabotage attempts by the other side,” she says.
