Attitude control is an important basic function for most spacecraft. The primary objective of this experiment was to improve the capability and flexibility of a reaction wheel attitude control system by introducing variable inertia reaction wheels. This enhancement might provide at least two advantages: variable precision and vehicle reorientation without changing the reaction wheel angular velocity. To demonstrate these advantages, a prototype of a variable inertia reaction wheel system was flown in a microgravity environment aboard NASA's KC-135A "Weightless Wonder V" aircraft as a free floating experiment. The data collected during flight suggests the control system performed well, and that a variable inertia system offers increased flexibility in attitude control.