Servers in dawn-dusk orbit

Despite the predictions that no one would ever put build data centers in space, Google is starting on Thursday. Google’s prototype satellite will be one of 130 payloads on SpaceX’s Transporter 18 mission on October 1. The server will follow a dawn-dusk orbit, a special case of a sun-synchronous orbit (SSO), following the terminator line between daylight on dark on the earth below. A dawn-dusk orbit allows the satellite’s solar panels to stay in nearly continuous daylight, while also being in a relatively inexpensive low earth orbit (LEO). Geostationary orbit (GEO) would allow solar panels to always receive sunlight, but launching a satellite into GEO requires more fuel and so is more expensive. A dawn-dusk orbit would not be possible if the earth were perfectly spherical. The earth’s equatorial bulge makes it possible to design an orbit that precesses once per year. David Hammen explains this in an answer to a question on the Space Exploration Stack Exchange site. If the Earth had a…