Results are presented of an experimental and analytical investigation to determine the feasibility of using active control techniques to (1) attenuate the response of a flexible payload to low frequency sinusoidal vibration disturbances, (2) damp the transient response of a flexible payload to step disturbances, and (3) eliminate isolator static deflections under conditions of gradually changing steady acceleration levels. An active vibration isolation system was developed and an experimental working model of the system was built and tested. Digital and analog computer studies were conducted to obtain the transmissibility and transient response characteristics of the isolation system. The analytical and experimental results indicate that the active vibration isolation system is very effective in attenuating the response of a one- and two-degree-of-freedom payload to vibratory disturbances. / Master of Science