Also see SpaceX Delays Launch of Starlink Orbital Internet Satellites | NYT and SpaceX Is Banking on Satellite Internet. Maybe It Shouldn't | Wired
"On Twitter, Musk recently wrote that the company would need to put up six more batches of 60 satellites for “minor” coverage for what it calls its Starlink program, and an additional 12 batches for “moderate” coverage. But he warned that “much will likely go wrong on 1st mission.”Elon Musk’s SpaceX is striving to win the race to build the Internet in space | Washington Post
In a call with reporters, Musk cautioned that “there is a lot of new technology here, and so it’s possible that some of these satellites may not work. In fact there is a small possibility that all of the satellites might not work.”"