ATTITUDE SIMULATION SOFTWARE TO SUPPORT BRAZILIAN SPACE MISSIONS Valdemir Carrara

Abstract: Cost reduction on system tests with hardware in the loop during qualification phase of the on-board attitude control software imply in increasingly simulation realism. Attitude simulation software not only has to mimic the dynamical behavior of the spacecraft, but also shall be easily configurable, to adapt to different orbit, attitude pointing requirements, environment disturbances, sensors, actuators, and to run in real-time among other minor requirements. As the requirements for accuracy and stability for attitude pointing has increased in many modern missions, so do the complexity of the simulation algorithms and necessity for dynamical realism. Rigid body dynamics can be considered excessively simple to model a satellite with several reaction wheels, non-rigid structures, unbalanced solar arrays, fuel and liquid sloshing, not to mention crew motion and vehicle docking. This work presents the efforts being carried out to fulfill the requirements of the Brazilian space missions, nominally Multi Mission Platform, with a simulation environment capable to accomplish from early definition and mission analysis phase up to acceptance tests of the attitude control software. Development is being conducted in order to achieve a high degree of realism and range of applicability of the simulation software, compatible with the expected cost reduction of the simulation hardware (ordinary PCs). The kinematics and dynamic models to support AOCS (Attitude and Orbit Control Subsystem) simulation and testing with or without hardware-in-the-loop fo