The "runways" of the orbiting spaceport are tracks built into the major chords of a long horizontal truss. The natural orientation for such a truss -- i.e., the minimum energy orientation -- would be vertical, aligned with Earth's gravity gradient. It requires active control to maintain the metastable equilibrium of the horizontal orientation.

As active control systems go, the system needed to maintain the spaceport's horizontal orientation in orbit is simple. Departures from the metastable equilibrium develop slowly, can be measured with high precision, and can be corrected quickly. The main difficulties involve assurance of reliability, management of backup modes, and integration with other spaceport subsystems.

There are three independent means available to correct drifts away from the metastable equilibrium point. In orbit, the spaceport rotates end over end at an average rate of exactly one revolution per orbit. The rate of revolution can be controlled over a small range with minimal expenditure of energy and no expenditure of reaction mass by varying the spaceport's rotational moment of inertia. That can be done by varying the distribution of mass along the truss, or by varying the length of the truss itself. The former can be done by shifting the positions of energy storage units or other movable masses. The latter cann be done through servo units operating at the junctions between truss segments. Servos between truss segments also enable controlled bending of the trust. That enables the truss to resist buckling under compressive loads.

The second means to correct drifts is through torque applied to gyroscopes or momentum wheels. That doesn't change the rotational moment of inertia of the spaceport itself, but it exchanges rotational inertia between the truss structure and the gyroscopes or momentum wheels distributed along its length.

The third means is via sets of steerable high impulse ion thrusters deployed along opposite sides of the truss. The thrusters are required in any case to maintain the spaceport's orbit after unbalanced catches and lauches have disrupted it. They are also needed for maintaining an optimal fixed orbital plane for the spaceport to accommodate shuttle launch windows. They can also be used for attitude control. However the high power draw of ion thrusters and the need to replenish reaction mass relegates them to use as backups if for some reason the first two m3qnw or control can't be used.