Star said I needed Sigma, but I had the Theta upgrade?

I went to visit a Red star and the system indicated that I needed the Sigma Warp drive.

I find this request strange as I already had the Theta upgrade (highest warp drive).

Why would it require me to have a lower end warp drive when I already have the highest upgrade?

Perhaps this is like trying to fly from my house to the corner store in a leer jet versus a bicycle, or are there other factors I'm not considering?

Solution 1:

If you take a look at Does the different coloured solar system mean anything?, the answer goes into detail that each colored star system requires a specific Warp Reactor to get to.

This is mere speculation, but instead of it being a matter of "perhaps this is like trying to fly from my house to the corner store in a leer jet versus a bicycle", it is more-or-less a preventative for players to farm-hunt for the Warp Reactor Theta and be able to travel through the entire galaxy with a single Warp Reactor upgrade; especially for those who happen to find the Warp Reactor Theta as their first upgrade