Three years ago, Alphabet (then just “Google”), announced an ambitious plan to help bring internet access to remote regions via fleets of solar-powered balloons. Now, it looks like it’s finally going to become a reality. Later this year, Project Loon is going to start testing service with carriers in Indonesia.

project loon, alphabet, google, x labs, internet access, solar powered balloons, wi-fi, developing nations

Why has it taken three years to get this project off the ground, so to speak? Astro Teller, the head of Alphabet’s X innovation lab, explained in a recent TED talk and Medium post some of the challenges his team has had to overcome. The first major roadblock was simply pinning down a viable balloon design — they had to be able to stay in the sky for months on end, be able to navigate with extreme precision, and do it all at a reasonably low price point.

Last year, Teller’s engineers finally hit on the perfect formula, and managed to navigate a balloon on 19 round-trips across the world over the course of 187 days. They’ve also been hard at work improving the speed of the internet connection the balloons will deliver via an aerial wireless network. The wi-fi can now hit speeds of up to 15 megabits per second, fast enough to steam video.

Related: Project Loon: Google Launches Solar Powered Balloons to Bring the Internet to Off-Grid Areas

There have also been some practical problems on the ground that have gotten in the way — for instance, in Sri Lanka, the company had to negotiate with the government in order to access a needed radio frequency. (The country agreed on the condition that it would receive a stake in Project Loon.)

While Project Loon looks like it’s on the verge of success, other Alphabet X lab projects haven’t fared as well. Teller revealed that some of his other projects have even been abandoned all together, including an effort to ship physical goods via “a lighter­-than-­air, variable buoyancy cargo ship,” and a vertical farming initiative.

Related: Google Buys Solar-Powered Drone Manufacturer Titan Aerospace to Boost Internet Access in Third World Countries

The cargo shipping project was simply too expensive to implement, at a cost of $200 million to build just one rocket, but the vertical farming project failed because Teller’s team was simply unable to figure out how to get certain staple crops like rice and other grains to grow in “stacked” arrangements.

+ Project Loon

Via FastCompany