[QUESTION] Would It Be Possible...

[XxLOLdudexX]

...To make a non-linear sector progression? I was planning to make a universe where one can roam freely with a main quest line and optional side quests, but I'm just seeing if I could make a perhaps circular sector map?

[Kieve]

Sadly no - not without editing the executable itself, anyway. When it comes to straight sector-to-sector jumps, it will always be forward until Last Stand, no going back, and no side-hopping to other sectors.
The only way "Infinite Space" manages to sidestep this restriction is by repeatedly calling an event that transfers you to the "secret" sector, at the exit beacon of each system. This allows for an infinite loop of secret sectors, but does not permit any natural progression through the rest of the game - no Mantis Homeworlds, no Pirate or Civilian sectors, etc.

[Ora_unit_SR388]

This is why we need to be able to source mod.

[speedoflight]

This is why we need to be able to source mod.

This and hundreds of other things...