<div class="htmlview paragraph">This paper summarizes the main considerations in applying a Twin Gyro Controller and the problems in implementing such a controller. Several Twin Gyro Controllers have been built for the purpose of measuring disturbances on a space vehicle, and the construction problems encountered are reported.</div> <div class="htmlview paragraph">The main problem areas encountered involved alignment torquing provisions and mechanical tolerances. The three-axis Twin Gyro Controller was spun up to synchronous speed before launch and, as a result, the spinning of the spin stabilized vehicle introduced additional loads on the gyro wheels and torquers. These loads resulted in the use of a spiroid gear drive in the gyro torquer closed loop.</div> <div class="htmlview paragraph">Considerations in applying the Twin Gyro Controller as an attitude controller and as a measurement device are covered in terms of sensitivity, accuracy, and limitations.</div>