SpaceX successfully launched another 60 starlink satellites. There are now be 180 production starlink satellites in orbit. There are about 49 of the test production satellites. It is not known if the test production satellites can be used for the commercial network.
420 satellites are needed for minor broadband coverage of Earth and 780 of the first ~1600 for moderate coverage.
SpaceX is four successful starlink launches from minimum global coverage and ten starlink launches from moderate coverage.
SpaceX expects more than US$30 billion in revenue by 2025 from its satellite constellation, while revenues from its launch business were expected to reach US$5 billion in the same year.
Internet traffic via a geostationary satellite has a minimum theoretical round-trip latency of at least 477 ms (between user and ground gateway), but current geostationary satellites have average latencies of 600 ms or more. Starlink satellites would orbit at 1⁄30 to 1⁄105 of the height of geostationary orbits, and will have Earth-to-sat latencies of around 25 to 35 ms. This latency will be comparable to existing cable and fiber networks. The latency will be lower for Starlink than any earth system for distances greater than 2000 miles. This is because light travels faster in a vacuum than in a fiber. The system will use a peer-to-peer protocol simpler than IPv6. It will have end-to-end encryption natively.
Starlink satellites use Hall-effect thrusters with krypton gas as the reaction mass for orbit raising and station-keeping. Krypton Hall thrusters tend to exhibit significantly higher erosion of the flow channel compared to a similar electric propulsion system operated with xenon, but at a lower propellant cost.
Successful deployment of 60 Starlink satellites confirmed! pic.twitter.com/AHkQYB3uNV
— SpaceX (@SpaceX) January 29, 2020
Another 60 #Starlink satellites are now in orbit courtesy of the #SpaceX #Falcon9 on its third flight. The first stage successfully landed on OCISLY and a fairing half was caught! pic.twitter.com/e7JfZioEvJ
— Richard (@RDAnglePhoto) January 29, 2020