Eye in the Sky
Class Description
There are over 8,000 functioning satellites circling our planet (doubled in the last 2 years) in three basic orbital bands, with another hundred or so parked in a graveyard orbit. Their functions include earth observation, navigation/positioning, satellite TV, Internet provisioning, research, military observation and other communications roles. For a fun look at the wide variety of services provided by these satellites I suggest you view this video, which addresses the consequences on our world today of a sudden disappearance of all artificial satellites.
In class we will review the basics of orbital mechanics to understand the logic behind placing satellites in these different orbits based on their functions, and examine the essential components of satellites, especially communications satellites. I suggest you view this video for a nice introduction to the topic (somewhat dated but accurate with fundamentals).
We will do a deep dive into two special classes of satellites: navigation and Internet provisioning, exemplified by the GPS (formerly Navstar GPS) and Starlink constellations, respectively. GPS and systems like it rely on a fleet of satellites in medium Earth orbit that broadcast their locations via a timestamp that our phones and other devices receive and use to compute location as long as 4 satellites are “in sight.” View this video to see why we need a minimum of four satellites to provide a location accurate within a few meters.
Much of what we believe about Starlink technology is based on best guesses by experts, largely drawn from FCC filings. A reasonable explanation is given at this website, which contains both videos and written explanations. Feel free to browse, but focus on the basic architecture including ground stations and the fleet of thousands of satellites in low earth orbit, enabling quite respectable bandwidth compared to fiber cable-provisioned internet, and the possibility of Internet access even at sea.
We then look at the downside of satellite proliferation from the standpoint of orbital debris and interference with especially earth-based astronomy. We will conclude with examination of recent developments regarding potential militarization of space.
