Torquer

#Magnetic torquer rods (also known as torquers, torque rods, torque bars, torqrods, or magnetorquers) are widely used as attitude control system (ACS) actuators for geostationary satellites, small satellites, and microsatellites. A magnetic torquer rod is essentially a long copper wire wound around a core. The core material could be special alloys or simply air. With a metal core, the magnetic torquer rod can generate a larger magnetic dipole moment at the expense of a larger residual moment as compared with the air-core type. Magnetic torquer rods are designed to generate controllable magnetic dipole moments that interact with the Earth’s magnetic field and generate torques for active attitude control purposes for spacecraft (Sidi, 1997;Wertz, 1978). Torque Tmag of a magnetic torquer is given by the cross product of its magnetic dipole moment M and the Earth’s magnetic-field vector B, i.e., Tmag = M × B. Magnetic control systems have the characteristics of relatively light weight and require no moving parts, expendables, or complex hardware.