(Image Credit: pixabay)
For over twenty years, the Trans-Atlantic Telephone 8 (TAT-8) cable sat on the ocean floor in its out-of-operational-use state. Now, SubSea Environmental Services is pulling it from the seabed close to Portugal. The world’s first fiber-optic cable became operational on December 14, 1988, and retired in 2002 after 14 years of use, when a fault made it too expensive to repair. TAT-8 reached full capacity within 18 months, setting a precedent for other major undersea cables.
SubSea Environmental Services is using the new diesel-electric MV Maasvliet vessel to recover the cable. However, the crew couldn’t retrieve as much cable as they anticipated as the early hurricane season veered the ship off course. Due to the glass fibers’ fragility, the fiber-optic cable must be manually laid in the ship’s hold rather than being mechanically coiled.
Developed through the mid-1980s by AT&T, British Telecom, and France Telecom, the TAT-8 represented a transitional mark from copper coaxial to optical technology. Spanning 3,700 miles from Tuckerton, New Jersey, it connected to Widemouth Bay, UK, and Penmarch, France, via an underwater branching unit off the British coast. To support this, AT&T introduced developments for the cable, such as the 1.3-micron single-mode fiber, high-strength splicing, lasers/detectors, and 280 Mbps silicon repeaters placed 24 miles apart.
In total, the project cost between $335 million and $351 million to complete. It overcame challenges, including corrosive saltwater, precise splicing at sea, and extreme pressures, before being deployed in the ocean. Its repeaters were pressure-tested at depths of 8,000m, and fibers were engineered 10 times stronger than land variants for tension resistance during laying. Lastly, opto-electric regenerators reduce hardware requirements by 75% compared to copper-based cables, utilizing compact lasers every 40-50 km instead of bulky analog amplifiers. This setup achieved 40,000 simultaneous voice circuits on two fiber pairs, with the US segment host to an extra pair.
While TAT-8 transmitted data over glass fibers, it has recyclable materials like steel and polyethylene for fences and plastics. Plus, it contains high-grade copper in the power conductors and armoring. Copper supply is tightening, so recovering and recycling it for different purposes rather than leaving it on the ocean floor makes more sense. Abandoning the cable down there poses a risk of snagging fishing gears, trawlers, or ship anchors, potentially damaging vessels or entangling marine life.
We also need to keep the ocean floor clear for new cables. As it stands, unused, old cables extend millions of miles. Getting rid of them frees up space, allowing new systems to reuse those routes while leaving the surrounding seabed untouched. This ensures the installation is a safe and smooth process. Google, telecom consortia, and Meta have invested billions into new cables, with some, like Google’s Firminia 1, Apricot, and Nuvem, expected to complete this year. Meta-led Project Waterworth plans to construct the world’s longest subsea fiber-optic cable using 24 fiber pairs at 30,000+ miles long that spans five continents.
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