SpaceX’s Starlink surpasses 2M active customers
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https://arstechnica.com/tech-policy/2023/09/spacex-projected...
2015 is when they first opened the early development facility in Redmond. No hardware, not even prototype hardware, no government applications filed. Didn't even have an office building.
The entire design of the system went through multiple massive revisions before it even launched the first test satellites, as well as a firing of most of the entire executive staff (who went to work for Amazon, which still has yet to launch any of their satellites).
In a presentation[1] in 2015 to a group of people (early employees?) he mentioned that they plan to launch prototypes in "3 months" (standard Elon time), they didn't launch any prototypes until 2018. That'll kind of throw off your plans to getting to 20 million.