This manual page explains attacking in PW.
Manual > PlanetWars > Attacking
A large part of PlanetWars is attacking and defending planets by playing 2v2 or 3v3 Zero-K battles. A successful attack brings the attacking faction closer to gaining control of the planet.
There is a bar, called the PlanetWars bar, at the bottom of Zero-K Lobby and at the top of the main page. This bar is used to sign up for battles. The text on the buttons on the bar is white if your faction needs players to sign up for a battle, otherwise it is black.
Players are able to sign up to attack or defend while already in a game but will be kicked from their current game when the battle that they signed up for begins. So be warned, do not sign up for a game and then play another if you do not want your game to end abruptly.
If the PlanetWars bar contains two or more buttons with white text then it it your faction's turn to attack. Each button contains the name of a planet, an indication of how many players have signed up to attack that planet and the required number of players to start the battle. Click a button to sign up for a battle to attack that planet.
Initially you are presented with a choice of two planets to attack. These planets are automatically recommended but are not necessarily the best targets. If you want to attack a particular planet click on the planet on the main page and click the "ATTACK PLANET" link. This link will add a button to attack that planet to the PlanetWars bar and automatically sign you up for the battle. Any adjacent planet or planet with dropships can be targeted for an attack in this way.
The PlanetWars bar has a timer on the left. If the timer expires while a faction is picking a planet to attack they lose the initiative and the other faction gains the ability to attack.
If the required number of players for a battle is reached a Challenge is sent to the opposing faction. The signups for other planets are cancelled at this point because only one attack can occur per turn. Be aware that if you cause a challenge your battle can start at any time within the next 10 minutes so be ready to fight.
A battle requires players from both the attacking and defending factions. The attacking players are determined by the process of initiating the attack the defenders are determined by responding to the challenge that attack creates. Signing up to defend is much like attacking. When defending, the PlanetWars bar contains a single button to sign up for the defense of the attacked planet. The battle begins when the required number of defenders sign up.
Players of the defending faction have 10 minutes to sign up for defense and the remaining time is shown on the left of the bar. If by the end of 10 minutes the defending team has one less the the required number of players a battle will start with uneven teams. This can cause 2v1 or 3v2 battles to occur. In this case one player on the defending team will receive two commanders.
If after 10 minutes there are too few defenders the battle is automatically lost.
For more details on Influence and capturing planets see the Influence page. For turn and initiative mechanics see the turn page.
For the most part the battle is an ordinary Zero-K game. There are no bonuses at the galactic level which give one side of the battle any advantage. The difference between normal Zero-K games and PlanetWars battles is in the optional objectives.
Each side has a Command Center. These structures affect how much Influence the attackers will gain from the battle. If you lose a battle but manage to destroy your opponents Command Center then the outcome is better than if you had just lost. Similarly if you are win a battle then it is much better to win with your Command Center in tact. It is a good strategy to try to kill your opponent's Command Center just in case you lose.
Battles can contain more than just the Command Centers. Most of the infrastructure present on a planet will appear in the battle as well. Any infrastructure destroyed in a battle will be disabled for several turns. If the attacker wins the battle then all infrastructure is automatically disabled. So as an attacker consider destroying infrastructure if it looks like you may lose and if defending make sure to defend vital assets.