SpaceX Starlink stack ready for deployment (Source: SpaceX)

First batch of SpaceX Starlink satellites in orbit

On May 24, 2019, SpaceX launched its first 60 Starlink satellites into Low Earth Orbit (LEO).  Most of the satellites are fully operational and are now in the process of climbing to an in-service orbit of 550 kilometers. SpaceX may launch anywhere from 2 to 6 more launches by the end of the year with 60 satellites per launch to get to 400 satellites for a minimal operational capability to deliver broadband.

Around 56 of the Starlink satellites are working well, according to SpaceX President and COO Gwynne Shotwell, with four of them having some issues but still in communications with the ground.  Shotwell made the comments about reliability at a May 29 talk at MIT. A statement issued by SpaceX on May 31 said all the satellites have successfully deployed solar arrays, generated positive power, communicated with the company’s ground stations.

One unexpected controversy emerging from the SpaceX Starlink launch is the potential impact a fully deployed system may have on astronomy.  The initial deployment “train” of 60 satellites was readily visible on the ground.  Astronomers are concerned the bright satellites will interfere with time-lapse and other observations as more satellites are launched.  SpaceX is licensed to deploy up to 12,000 satellites in orbit, but it first needs to get to around 1,000 or so for coverage of the entire globe and be economically sustainable.  A constellation of 12,000 shiny satellites by SpaceX plus other constellation projects will put a lot of shiny noise into orbit for ground-based telescopes to cope with.

The first-generation production Starlink satellites each weigh around 227 kilograms.  Unlike traditional satellites, Starlink is a relatively thin flat panel design enabling a large number of satellites to be stacked together for launch on a single vehicle.  Each satellite has multiple flat-panel antennas on the “bottom” facing the Earth and a single solar array that unfolds perpendicular to the rest of the satellite.  Features include a star tracker navigation system derived from work on the SpaceX Dragon capsules, the ability to conduct autonomous collision maneuvers, and the first ion thrusters using krypton gas.

Significant features not included onboard the first generation of satellites are support for Ka-band communications and optical (laser) crosslinks between satellites.  Both elements were dropped and will likely be rolled into future versions. 

Stripping out the optical crosslinks means Starlink satellites will have to relay data between themselves by using one or more “ground bounce” ground stations.  Each ground bounce will add additional latency, an unwelcome addition that detracts from assertions Starlink would

SpaceX CEO and founder Elon Musk says it will take around 24 launches to provide service to most of the populated world with 30 launches putting up enough satellites to cover the entire world.  Each orbital plane of 60 satellites delivers around 1 terabit per second of useable broadband service, so adding more useable broadband means adding more satellites.

Doug Mohney

Doug Mohney, a principal at Cidera Analytics, has been working and writing about IT and satellite industries for over 20 years. His real world experience including stints at two start-ups, a commercial internet service provider that went public in 1997 for $150 million and a satellite internet broadband company. Follow him on Twitter at DougonTech or contact him at dmohney139 (at) gmail (dot) com.

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