oh ok.. I have just got my interplanetary probes and am exploring the galaxy
You are playing on Kation's not TPEHEP space map, so this discussion is in wrong thread
Fog of war always is here, unless you meant unexplored tiles, those are revealed with Satellites.
As for units you can use those on space terrains - some units give mission rewards.
There are space resources that kinda act as anomalies - they increase yields from tiles, but no improvement does anything with them and they doesn't give tradable resources unlike rest of map resources.