SpaceX has announced a launch target of May 2019 for the first batch of operational Starlink satellites in a sign that the proposed internet satellite constellation has reached a major milestone, effectively transitioning from pure research and development to serious manufacturing. R&D will continue as SpaceX Starlink engineers work to implement the true final design of the first several hundred or thousand spacecraft, but a significant amount of the team’s work will now be centered on producing as many Starlink satellites as possible, as quickly as possible.
With anywhere from 4400 to nearly 12,000 satellites needed to complete the three major proposed phases of Starlink, SpaceX will have to build and launch more than 2200 satellites in the next five years, averaging 44 high-performance, low-cost spacecraft built and launched every month for the next 60 months.
My question is how many in the first batch, twenty-five, or more. One estimate:
Using a Falcon 9 at 25 satellites per launch it would take 177 flights, about 36 flights per year. Using a Falcon Heavy with 40 satellites it would take 112 flights, over 5 years that’s about 22 flights per year. Using a BFR assuming 350 satellites per launch, until someone comes up with a better number, would need 13 flights total.
Source: Reddit Starlink FAQ