An Experimental Approach to Mapping of Magnetic Fields of CubeSat Attitude Actuator Representations

In a compactly designed satellite, particularly those hosting magnetic or electric motor based actuators, the magnetic field distribution is continuously changing and can adversely affect the sensor/instrument measurements captured for attitude/orbit computations or science data collection. The purpose of this study is to elaborate on a 2-step process for mapping the magnetic field of a compactly designed satellite. The 2-step process involves, (i) carrying out experiments in a Helmholtz cage (HHC) to obtain discrete measurements of the satellite magnetic field, and (ii) performing a Fourier analysis to extrapolate the discrete measurements into a continuous map. A tri-axial HHC with precision magnetometers is set up to facilitate the measurement of magnetic field of CubeSat components - permanent magnets, magnetic torquers, etc, in a three dimensional (3D) space. Upon satisfactory calibration of the HHC, an electromagnet emulating a CubeSat magnetic torquer is placed on a rotating platform inside the HHC. The HHC is pre-configured to negate the effect of Earth's magnetic field. Using a DC supply as a power source, various intensities of currents are passed through the torquers. For various values of the current flowing through the torquers, precision magnetometers are used to measure the magnetic field generated by the torquers. The discrete magnetometer measurements are used in a Fourier analysis to develop continuous maps of magnetic fields. The magnetic maps, thus developed, facilitate an understanding of the adverse effects of satellite magnetic field on sensors, instruments. The underlying intent of the research is to investigate compensation approaches to address the adverse effects of the satellite magnetic field on its sensors and instruments.