Abstract Highlighted in this paper are the special design features incorporated in the Attitude Determination and Control Subsystem (ADACS) of the STC Direct Broadcast Satellite (DBS) presently under construction at RCA Astro-Electronics in Princeton, New Jersey, USA. The design has evolved from the control concepts developed for the RCA Satcom and Anik B spacecraft, which, in normal on-orbit operations, use the RCA Stabilite ® three axis attitude control principle. However, the heritage design had been significantly altered to improve the pointing capability as well as to improve control automony. The main feature of the communication payload which drove the design of the DBS control subsystem is the use of six 220 Watt traveling wave tube amplifiers (TWTAs). This, in turn, requires considerably larger solar arrays, extending approximately 7.9 meters from both the north and south panels of the satellite and supplying 2.6 kwatts of power to a dual bus system of 100 and 35 volts. The communication antenna itself, with a 2.2 meter aperatuce, extends 1.7 meters outward from the satellite's west side. The modal characteristics of the flexible solar arrays and the relatively high disturbance torques, generated by the thrusters on one hand and the microwave emission from the antenna reflector on the other, made heavy demands on the ingenuity of the control designers. Design innovations such as autonomous bias torque estimation and thruster impulse matching ate described together with the corresponding pointing accuracy improvements.