Center of mass
The center of mass, abbreviated CoM, is the location of an object where all mass is equally distributed around it. It is important to balance a craft to prevent it from getting out of control. Planes should have a center of mass slightly in front of the center of lift. For all craft the thrustvector should point to, point away from or go through the center of mass.
It is possible to show the center of mass in the Vehicle Assembly Building and Space Plane Hangar, but not while in flight. Also it is not possible to view the center of masses of the different stages.
- Center of mass on Wikipedia