AttSim is a spacecraft attitude simulator that has been specifically developed to design and verify attitude control concepts and flight software architectures and algorithms. Its primary goal is to provide a generic approach to small satellite attitude control development by allowing scalable performance. AttSim specifically allows the user to develop software modules that can be used as flight code, and to verify control logic, controller gains, and other mission-critical elements. The code can be developed in a flight-like environment, allowing quick conversion to actual flight code for a target processor. In addition, AttSim can be used as a systems engineering tool to ensure correct torquer, wheel, and thruster sizing and sensor performance. AttSim allows derivation of subsystem requirements to meet attitude accuracy (pointing and stability) goals. Its use during all phases can help reduce development and verification time as well as cost and risk. Several missions have been developed to verify the AttSim system architecture and the cost savings associated with its implementation. The simulator\u27s performance has also been verified using actual mission data, showing the simulations deliver realistic data. Using this accelerated, integrated development approach for the attitude control system, small satellites can be developed at lower cost and risk
