Attitude control
For attitude control, a gyroscopic stabilization mode has been selected (at low rotation speed, with the axis of rotation oriented parallel to the axis of the dipole of the geomagnetic field) in which the interaction of the terrestrial magnetic field with the actuators is used. in UPM-Sat 1 both for determining the attitude of the satellite and for carrying out control maneuvers.
The attitude control subsystem consists of sensors, actuators, and control logic. The sensors are two Ultra Electronics TAM 7 MK2 S triaxial magnetometers and three Sextant Avionique J176 ALM gyroscopes.
The attitude control subsystem actuators are six coils connected in parallel two by two so as to form three pairs of magnetocouples. One of these magnetocouples has square-shaped coils, 425 mm on a side, located around trays A and D; the other four coils are rectangular, 530mm x 425mm, and are arranged around the side walls.
Each magnetocouple is formed by a series of turns of copper wire of 0.4 mm in diameter, with a cross section in the shape of a right triangle with two equal legs of 10 mm on each side. The coils have been built with enameled copper wire, made with Thetic Polyester-Polyamide resins, class H, with a temperature index of 180°C, CEI 317/8 recommendation. In the manufacture of the coils, the UNE 20.006 IV-V(W) standard and the DIN-46435 and 46453 standards have been followed with regard to measurements, electrical and mechanical tests in grades 1, 2 and 3. Each coil is coated with kapton tape.
