Recon Satellites

[Intimidator]

At least it's a cheap an easy way to watch your adjactent systems in a early game, by just dropping sats with only an computer core (drop them in storms when available or otherwise drop them in the left-top corner, maybe your opponent will not notice your sat at that spot through the system name )

[Fyron]

The system icon on the galaxy map changes to a triangle though.

[Intimidator]

I know, but it is easily overlooked (if you are lucky).....

Inti,

[Blueentity]

One of the other uses for a "spy" sat is in a nebulae sector to "see" the hidden ships.

[Arkcon]

When I get the tech, I like to put a fighter base in a nebula. If its one of the shield depleteing nebulae, a pack of armored fighters will make mincemeat out of the average shielded ship.