I loved those books!
By chance does anyone know what they might have been?
https://www.worldcat.org/title/high-frontier-human-colonies-...
https://www.worldcat.org/title/colonies-in-space-a-comprehen...
https://www.worldcat.org/title/high-frontier-human-colonies-...
https://www.worldcat.org/title/colonies-in-space-a-comprehen...