Proviso: Planets/Stars/Asteroids block sensors, so some systems need more than 4 Sats to cover all the area.
I also think there's currently a bug/feature that unless you have an entity sharing sensors directly on the square with the planet/asteroid, the sensors do not cover that square.
I'll share it here again as it's somewhat relevant, and will also let you substitute sensor values for stations. Sensor Shadow/Power Calculator
Eventually I'll get around to making it actually work for multiple entities so all the power values are calculated properly.
then use 20 if you feel like wasting time and money. I have set up sats in a few systems and I have never needed more then 4. Apparently some places need more, I personally have never seen where more then 4 was needed.
