Ground validation of the inertial stellar compass

The inertial stellar compass (ISC), under development at Draper Laboratory, provides spacecraft attitude determination to 0.1 degree accuracy using just 3.5 W of power. This work describes the process of validating the performance of the instrument on the ground prior to characterizing it on orbit. Starting with subsystem-level testing of the ISC´s active pixel sensor camera and MEMS (microelectromechanical system) 3-axis gyro board, we describe the operations leading up to integrated system testing of the camera and gyro sensor outputs, which are combined to provide a robust attitude solution over a wide range of operating conditions. Under the guidance of NASA´s New Millennium Program, the ground validation process, which will be followed by an on-orbit demonstration, will make feasible a new class of low-power, integrated attitude sensors for small spacecraft.