Well, you can see active sensor coverage in the system map if ticked, and manually activate sensors on ships by means of the fleet or combat screens.
As for the economy, yes, thats meant to be that way.
It's a choice.
Bigger pop starts may have less of a problem with that, with more spare tax payers.
If you have spare Corrundium and Uridium, try building some financial centers, and try colonizing near planets.
Get a civilian spaceport on every population above a few millions, and once you have civilian shipping lines, they will trade between the planets generating wealth.
Normally, the first Expand Economy tech is way enough, the rest is better spent in Research speed.
If you want to produce non-stop, you need less shipyards and factories