New Station
From Space Engineers Wiki
This function can be accessed by pressing "G" while in human form, then you must select the option "Create a New Station". When you do this, an armor block will be placed in front of you. You can then build off of this block.
Size of a Space Station
These stations are large and unmoving docks for fleets. They can be built in any size, and are the anchor places for ships, small to large. Their immobility allows for magnetic landing gear to attach to them at any angle. These stations require power, but do not need to waste it on thrusters and gyroscopes; just on turrets and gravity generators.