SpaceX today (May 3, 2017) appeared before a US Senate committee and stated that the company's planned constellation of 4,425 broadband satellites will launch via the Falcon 9 rocket starting in 2019 and will then continue to launch in phases until full capacity is attained in 2024.
A broadband infrastructure hearing was conducted by the Senate Commerce Committee and SpaceX offered the member an update on the firm's plans for their custom Ka- and Ku-band satellites to be LEO resident through the testimony of Patricia Cooper, the SpaceX Vice President of Satellite Government Affairs.
A possible launch date of 2019 was voiced by SpaceX when, last November, the firm filed their Federal Communications Commission (FCC) application. The satellites will occupy altitudes from 1,100 to 1,325 km and will be operational in 83 orbital planes. The launches will be handled by the company's Falcon 9 launch vehicle.
Ms. Cooper told the senators, "Later this year, SpaceX will begin the process of testing the satellites themselves, launching one prototype before the end of the year and another during the early months of 2018. Following successful demonstration of the technology, SpaceX intends to begin the operational satellite launch campaign in 2019. The remaining satellites in the constellation will be launched in phases through 2024, when the system will reach full capacity with the Ka- and Ku-Band satellites. SpaceX intends to launch the system onboard our Falcon 9 rocket, leveraging significant launch cost savings afforded by the first stage reusability now demonstrated with the vehicle."
She added that SpaceX intends to further boost capacity and reduce latency in locations of heavy access through an additional launch of 7,500 satellites, but gave no timeframe for this additional influx of orbiting spacecraft that will work at lower altitudes.