An orbital command center (in the previous game known as the Surveillance Station) is an upgrade to the standard Terran command center. Starcraft 2 Orbital Command tactics involve using the orbital command center to better assist their ground forces by using additional assets to help mine minerals and scan the battlefield. It retains all of a normal center's functionality (except that it cannot load SCVs, be changed back or upgraded into a planetary fortress) as well as including new functions.
Command centers are the main focus of all Terran outposts. They were originally designed to be roving resource processors for prospectors and they can fly to move on to new mineral deposits. While flying, however, they cannot produce units or upgrade into new buildings. Heavily armored and sturdy, they have the ability to manufacture SCVs and are the return point for these mining vehicles.
They include various new functions; for example, they take on the Scanner Sweep facility (previously available in the ComSat station) that enables a player to detect all cloaked units in a target area. In addition, they can call a MULE using a drop pod and, when dropped onto a mineral patch, the MULE has the ability to begin mining automatically.
The ability to deploy MULEs in this way makes the orbital command one of the most important structures in the Terran arsenal. MULEs are the most effective way to harvest minerals that you can then go on to use to build new units. MULEs cost 50 in energy and operate for only 90 seconds but can gather up to 300 minerals during a deployment. The ability for this expansion to summon a MULE is one of its most significant benefits. In addition orbital commands can call down extra supplies to a given supply depot (used when you are supply blocked) that increases your overall supply limit by 8.
It is a good idea to expand your natural with an orbital center instead of a planetary fortress when you begin a new game. The expansion is right next to your base, making it easier to defend. Also, when you have completed the upgrade from command center to orbital command you immediately have 50 energy available to use on a MULE.
Once you have the orbital command upgraded, you need to make sure that this vulnerable structure is defended. Siege tanks along with other units placed around it are a good way to do this with ground units placed in front.
If you're expanding away from your base, however, it's sometimes a better idea to build a Planetary Fortress rather than the Orbital Command so that it can defend itself while your units get to its location.
Starcraft 2 Orbital Command strategies involve using the specialized features of this upgrade to the Command Center to help increase your production in the Terran economy to match those of your enemy. If you cannot beat your opponent in several decisive battles then you may need to adopt the strategy of beating them economically.
