Facebook's Subsea Cable Will Become the World's Longest at 28,000 Miles

Facebook has announced the addition of a new leg to its undersea web cable 2Africa, which was first announced in May 2020 with initial plans to span 22,990 miles (37,000 km) across the ocean floor.

The cable that's connecting 23 countries in Africa, the Middle East, and Europe is now expected to run a total of 27,961 miles (45,000 km) once completed with the addition of the 2Africa Pearls leg, which will expand the cable as far as India and Pakistan, according to a press release by Facebook.

The 2Africa project, which was developed in collaboration with a number of global telecoms companies, is part of Facebook's larger goal to create an "open and inclusive internet ecosystem" and "bring people online to a faster internet." The new undersea web cable will bring much-needed capacity and reliability to Africa, where barely a quarter of people of its 1.3 billion people is connected to the internet. The cable was designed to serve 1.2 billion people in its original form, but the new segment will bring the total number of people served to 3 billion, or about 36 percent of the global population.

To make this a reality, engineers have designed the 2Africa cable to allow for a 50 percent increase in burial depth, ensuring maximum redundancy and availability. Moreover, the cable will be routed in a way to avoid the most problematic subsea locations, and all this is an effort to mitigate the traditional limitations of undersea cable networks.

Just a week ago, Google also finished laying its giant 3,900-mile (6,276 km) Grace Hopper subsea internet cable, which stretches the massive expanse of the Atlantic Ocean from New York to the U.K., before going onto Spain. But how are these two giants are laying thousands of miles of cables to carry the internet around the world?

What does it take to lay a subsea web cable?

According to a report by Business Insider, the companies must first plan the route that the cable, which can be as thick as a garden hose, will travel by completing a bathymetric and geophysical survey along the projected route, which can take up to a year. They dispatch sonar-equipped vessels to map the bottom and hunt for hazards including high currents, underwater landslides, and unexploded bombs or mines.

There is also the making of the optical fiber cable. For electricity conduction, optical fibers are wrapped in a copper jacket, but Facebook's 2Africa cable, for example, is made of aluminum rather than copper since it apparently reduces production costs and allows for longer links. After the route is mapped out, a specialized laying vessel uses an underwater plow to dig a trench along the seabed into which it lays the cable.