Today, February 17, SpaceX successfully put another of its 60 Starlink broadband satellites into orbit. The company now has conducted five launches for the Starlink program and put 300 of its own broadband satellites into space. Around 297 are currently operational.
The launch took place at 10:05 a.m ET from Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station, Florida. Fifteen minutes after launch, the Starlink satellites were successfully released and will undergo checkout before moving into their intended orbits and operational altitude of 550 kilometers.
SpaceX plans to put between 600 to 800 satellites in orbit in 2020 to offer coverage to the Northern U.S. and Canada with a full initial constellation of around 1400 satellites completed by 2021 to offer global broadband coverage. The company plans to conduct Starlink launches at a pace of twice a month this year through the end of 2020, an aggressive schedule that it so far seems to be meeting.
One potential hiccup to the 2020 launch plan is the availability of Falcon 9 first stages for re-flight. Today’s launch did not result in the recovery of the first stage; it instead splashed down next to SpaceX’s drone ship. The previous Starlink launch resulted in a rough landing for the first stage with the need to having to rework/refresh/replace the landing leg crumple zones designed to absorb the impact.
A pack of 60 densely-packed Starlink satellites are the heaviest payload the Falcon 9 launch vehicle puts into orbit. The Falcon 9 first stage needs to land downrange on a drone ship rather than turning around and putting down on one of the landing pads at Cape Canaveral.
More information on Starlink progress is expected to be announced at Satellite 2020 next month in Washington D.C. SpaceX CEO and founder Elon Musk is giving a keynote at the annual conference and will hopefully share more details about Starlink ground equipment and the overall network design.
Among the details will be how many ground stations Starlink will need and where they will be located. Due to Starlink’s relatively low operational altitude of 550 kilometers, the company will need to “ground bounce” traffic through terrestrial relay stations between different planes of satellites. Each “ground bounce” will add latency, with the potential to have to conduct multiple bounces depending on the number of ground stations and location.
Starlink’s relay architecture becomes even more interesting when users are far away from land, with the necessity for ocean relays in some circumstances and perhaps even polar relays for ships and aircraft. Competitors to Starlink call the need for ocean relays a “barge bounce,” while others have suggested strategically placed and equipped buoys may be an alternative solution. SpaceX’s ocean fleet of ships for Falcon 9 rocket and Crew Dragon capsule recovery may have to expand to deploy ocean relays.