A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2018 Sep 24, 20:15 -0700
Hi Steve! Welcome aboard.
When I saw your message as originally posted, I thought "wow! that's a crazy long subject!" Then I read the long message and realized, "aha! this is three messages". So I split it up manually, and it all worked out fine.
In this message, you wrote:
"chain-reaction collisions of satellites in geosynchronous orbit rendering the entire orbit unusuable."
This is not something that we have to worry about. Only LEO (Low Earth Orbit) is threatened by such a runaway scenario. And in any case, the GNSS constellations don't live in geosynchronous orbit! They are in MEO. There's a nice article with a good schematic drawing on Wikipedia: https://en.wikipedia.org/wiki/Medium_Earth_orbit. Of course that chain-reaction scenario is only one of the potential threats, but it's nice to know you can cross at least that one off, right?