There are several ways to enter into a space battle, listed below are all the different ways possible.
1. Launching an attack on another players planet.
2. Launching to invade a planet owned by another player.
3. Launching defence to a planet being attacked.
4. Launching an intercept fleet to stop an attacker/defender from reaching their target.
5. Launching an intercept fleet to intercept cargo transports.
6. Sending a fleet to station at someone elses planet.
7. Defending one of your own planets from an attack.
8. Declaring an incoming friendly/neutral fleet as hostile.
When a battle takes place around the orbit of a planet, certain things happen before a ship can fire its first shot. Any PDS that are on the planet surface
at the time of the attack, will shoot first. If there are any space stations in orbit as well, they will shoot after the PDS. Only then will the ships start
shooting at their targets.
Please Note - Only 4 of the 7 PDS available will target the hostile ships in orbit around the planet.