Scanning
You need first to build a Comms Satellite.
Your planet's Communication Menu gives you the ability to scan planets:
Resource Scan
The Resource Scan lists detailed planet resource and space information. It includes the planets abundance percentages of resources and the planets available land and orbital space.
( 500 per scan.)
Surface Scan
The Surface Scan lists all the information provided in the Resource Scan in addition to all buildings, Colonists and Soldiers currently stationed on the planet.
( 1000 per scan.)
Fleet Scan
The Fleet Scan lists all ships currently orbiting the planet or going to the planet.
( 2000 per scan.)