Hidden star lanes

Idea is to create star lanes that are initially invisible to vision and probes, and can only be revealed through a little extra work by the player.

This would add new possibilities for mid-game exploration. Discovering these hidden lanes could open new shortcuts, routes to previously undiscovered distant systems, new trade routes, or even new risks of invasion from rivals or pirates.

I can see a few different ways this could be implemented.

Option 1: Curiosities

Hidden lanes could only be revealed by surveying higher-level curiosities. These could be located in systems connected by the hidden lane, or they could be anywhere in that constellation, similar to how some curiosities reveal isolated nodes. This could also be used to discover wormholes, once you had the technology. 

Option 2: Must find both ends

Currently, if you find the nodes at both ends of a star lane, the entire star lane is revealed, even if you haven't actually used the lane. This option would basically do the same thing, except the ends of the lane would be invisible until both nodes had been discovered. So you would need to find both node A and node B, before you had any idea there was a lane linking them directly.

Option 3: Only visible at one end, invisible at the other

The lane would remain invisible to the player until a ship orbits the node at one end of the lane. Even if you knew where node A and node B were, you could only discover the hidden lane by one of your ships reaching node B via other means. 

Additional idea

These hidden lanes could have special properties too, like a movement bonus or malus to effectively make travel along them faster or slower. Or a size restriction, so only small and medium hulls could use them, for example.

Even without the special properties, adding hidden lanes could add a new dimension to mid-game exploration and navigation.