On Achieving Spacecraft Level Magnetic Cleanliness With Proper Equipment Ordinance of DC and ELF Magnetic Sources

Magnetic cleanliness is a severe electromagnetic compatibility topic in nearly all science space missions. Nowadays this interest is expanding from dc to the area of extremely low-frequency magnetic sources. This article presents an enhanced methodology to minimize the magnetic field at a volume in the vicinity of the spacecraft where sensitive instruments or measurement sensors are placed. A common process in early design stages of a space mission is to measure the candidate equipment separately and throughout this unit-level test campaign, a robust design of the system-level platform taking into consideration strict magnetic cleanliness requirements is developed. Based on this unit level magnetic signature characterization and through heuristic approach, the proper equipment ordinance or in case this is not possible the proper placement of compensation magnets can lead to system-level magnetic field minimization. The proposed methodology considers all the parameters of the equipment regarding dimensions, avoiding this way the overlap of the units inside the spacecraft providing feasible placement. Moreover, since the magnetic moment orientation and the center of the unit are the main optimization parameters, this methodology, when the appropriate measurements are available, can also include the induced magnetic behavior of the equipment. Authors prove with simulations that with appropriate equipment ordinance, the synthesis of a suitable electromagnetic environment is possible to be achieved.