Project Taara is one of the moon photo ideas from Alphabet X (formerly Google X). It was developed by Project Loon, a broadband project using balloons in the stratosphere since its closure.

The team wrote in a blog post that the latest experiment closed the "very harsh connectivity gap" between two African cities - Brazzaville in the Republic of the Congo and Kinshasa in the Democratic Republic of the Congo.

Cities are only five kilometers apart, but connecting is difficult because traditional cables have to be laid around rivers, making broadband five times more expensive. The X team said that the Wireless Optical Communication System (WOC) delivered nearly 700 terabytes of data in 20 days with 99.9% availability.

"While we do not expect impeccable reliability in all weather conditions in the future, we are confident that Taara's connections will continue to deliver the same performance and will play a key role in ensuring faster and more accessible connectivity for the 17 million people in these cities. " said the blog.

This is the final iteration of a project that has been in development for three years. X partners with Econet Group and Liquid Telecom to bring high-speed internet to sub-Saharan Africa and start commercial distribution in Kenya. This system uses a very narrow, invisible beam of light to deliver high speeds, similar to how traditional ground fiber uses light to transmit data, but without the cabling housing.

The technology known as free-space optical communication results from an experiment the team previously used to send lasers between balloons on Project Loon, which Alphabet discontinued in February because it was no longer considered commercially viable.

It's not perfect, and the team admits that it won't provide complete reliability under challenging conditions such as fog, fog, or birds flying in front of the signal.

But it has been improved by adjusting the power of the laser, which works a bit like a telescope and relies on mirrors, lights, software, and hardware to move the beam exactly where it needs to be. 

"While places like foggy San Francisco may never be the ideal place to use a WOC, there are many, places in the world with ideal weather conditions for a Taara connection," the blog said.