Facebook's drones might be able to stay aloft for months or years, he writes -- which is longer than the 100 days or so that Google has said its balloons could stay up in the stratosphere.
In large areas with low population densities -- think deserts -- Facebook may launch satellites as a cheaper alternative to drones. They'd be deployed either in low Earth orbit up to 2,000 kilometers overhead, or in geosynchronous Earth orbit, much higher at roughly 35,000 kilometers above sea level.
In low Earth orbit, the satellite's signal could provide access to fewer than 100 people per square kilometer, Zuckerberg said, with an even weaker signal provided by satellites higher up. But the FSO system could help speed that up.
For densely populated urban areas, mesh networks can be simple to deploy and cost effective, Zuckerberg said. Facebook will say more about those plans at a later date.
Zuckerberg touted some of the success the company has already had with the project, which it calls Internet.org. In the Philippines, it worked with a local operator to provide "free data access" to its apps, to make it easier for people to register for data plans, or in some cases to get loans for a plan. "In just a few months we helped double the number of people using mobile data on Globe's network and grew their subscribers by 25 percent," he said.
Working with another operator in Paraguay, Facebook helped grow the number of people using the Internet by 50 percent, he said.
The two partnerships together helped almost "3 million new people" access the Internet, according to Zuckerberg.
Internet.org is not only about providing access to Facebook, he said. It's also intended to help people get access to jobs, financial services and health care.
The entire project could be a big investment for the company. Looking at satellites alone, even if Facebook can build them cheaply and make them work, transporting them into space could cost hundreds of millions of dollars, Zuckerberg said, and there are regulatory issues, too.
And, of course, it will have to make sure its drones don't collide with one of Google's balloons, which would open up a whole new level of competition.
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