Lasers beam high-speed internet between cities through open air
Alphabet's floating internet venture Project Loon may have been deflated, but its legacy looks set to live on through a new effort called Project Taara. The team has salvaged the technology to deliver internet connectivity with lasers, demonstrating the viability in a new test between two cities separated by the Congo River.
Originally a Google side hustle before being spun off into its own project by parent company Alphabet, Project Loon had lofty goals of connecting remote regions to the internet by beaming lasers between high-altitude balloons. After years of successful trials however, the project was eventually grounded in January 2021 due to sky-high costs.
The balloons may have been a bust, but there’s still life in the lasers. After all, wireless optical communication systems could help connect communities where it’s not feasible to build complex grids of underground optical fiber cables, and where cellular or satellite internet is patchy or expensive.
Enter Project Taara, from Alphabet’s moonshot company X. For this latest tech demo, the team beamed an internet connection from Brazzaville, in the Republic of the Congo, to the neighboring city of Kinshasa in the Democratic Republic of Congo. While the cities are only 4.8 km (3 miles) apart, optical fibers delivering internet have to weave more than 400 km (250 miles) to bypass the Congo River. As a result, internet connections in Kinshasa are far more expensive.
Over 20 days, the link delivered almost 700 TB of data at speeds of up to 20 Gbps, with 99.9 percent availability. Of course, transmitting a narrow beam through open air will never be perfectly reliable, due to birds, rain, fog, and other interruptions, but getting the connection that stable is pretty remarkable.
Much of that comes down to the technology. The laser – invisible to the naked eye – is only the width of a chopstick, and it can precisely hit a target measuring just 5 cm (2 in) wide from 10 km (6.2 miles) away. The receiving terminal is designed to detect the light from the sender and lock on, automatically adjusting a mirror to maintain that connection even as the beam wobbles.
Still, even with that tracking technology the weather in some regions won’t be suitable for wireless optical communication. But the team says that most of the world should be able to get at least 90 percent annual availability.
It’s at least one more tool to connect remote regions and allow them to access the internet more reliably and, ideally, more affordably.