The attitude of the vehicle was measured relative to a coordinate system that was fixed just prior to launch with the X coordinate vertical, the Z coordinate in the direction of the pitch maneuver (down range, roughly East), and the Y coordinate perpendicular to the other two, cross range, roughly South. At the heart of the ST-124 was a platform that was held in a fixed orientation; hence the name "stabilized platform". It is connected by three gimbals that allowed the vehicle to roll, pitch and yaw but the stable platform to be held fixed in space. It was being translated, of course, but did not tilt during flight.