International space station leak localization using attitude response data

This paper presents a new method to localize air leaks on the international space station based on the spacecraft attitude and rate behavior produced by a mass expulsion force of the leaking air. Thrust arising from the leak generates a disturbance torque, which is estimated using a real-time unscented filter with a dynamical model, including external disturbances such as aerodynamic drag and gravity gradient. The leak location can be found by estimating the moment arm of the estimated disturbance torque, assuming that the leak is caused by only one hole. Knowledge of the vent thrust magnitude and its resulting disturbance torque is needed to estimate the moment arm. The vent thrust direction is assumed to be perpendicular to the structure surface, and its magnitude is determined using an extended Kalman filter with a nozzle dynamics model. There may be multiple leak locations for a given response, but the actual geometric structure of the space station eliminates many of the possible solutions. Numerical results show that the leak localization method is very efficient when used with the conventional sequential hatch closure or airflow induction sensor system.