Laying new a transoceanic internet cable is a massive undertaking -- laying one across the Arctic especially so. Arctic Fibre has grand plans to venture across the ice and the unmapped ocean floors, threading a trans-Arctic cable to finally connect London and Tokyo directly. Here's how.
The trans-Arctic cable is perhaps our 21st-century realisation of the Northwest Passage, a direct route from Europe to Asia that explorers have been searching for since the 18th century. The route didn't exist then, but it does now. Thanks to climate change, the Arctic is no longer frozen solid in the summer. That doesn't mean the Arctic can be called hospitable to humans or our ships though. Cable-laying ships will only be able operate without icebreakers for a limited window between August and October, complicating the whole operation.
But first, before the cables are even made, the entire length of the route has to be mapped to look for trenches and other hazards. Each length of cable is then custom-made for its particular stretch of ocean floor. Over at IEEE Spectrum, Amy Nordrum has a fascinating account of how the whole process will work.
This summer, the survey team will board a ship -- one like the RV Geo Explorer, owned by EGS Group -- to trace every meter of the proposed path. They will use multiple types of sonar, which measure echoes in different ways to scan and chart varying depths, landslide hazards, and unexpected volcanoes or chasms. Under the water, a metal detector called a magnetometer will help them steer clear of discarded fishing equipment or cables that have already been laid. Based on all of this data, the surveyors will build maps and plot a the cable's path, occasionally for areas of the passage that have never before been mapped.
Assuming that all goes according to plan, Arctic Fibre will start laying cables the following summer. It takes two passes for a cable ship to (very, very slowly) install the cable:
When the time is right, the cable is wound around big reels and loaded onto the back of one of three cable ships -- one for each ocean to be traversed. Those ships trundle along the route at about 2 km per hour, around the clock. In the ship's first pass over a segment, it drags a heavy anchor called a grapnel to smooth out the seafloor and remove any debris. During the next pass, the cable is fed from the back of the ship at a rate that speeds or slows with the ship's pace.
Shallow depths -- those less than 1000m -- are also tricky. A special plough on hydraulic skis is used to dig trenches to keep the cable safe from anchors and trawl nets. These precautions are especially important here because ships can't get through the ice to fix it if the cable breaks in winter.
When finished, the cable will connect London and Japan, but even more importantly, it will finally bring fast internet access to rural communities in Alaska and Canada. Our internet is still beholden to the limits of physical geography, for now. [IEEE Spectrum]
Picture: Arctic Fibre