Design Considerations of Passive Attitude Determination Control Subsystem for 1U ASEANSAT Satellite Project

The attitude control system on satellite that is used to handle and determine the orientation of the spacecraft in space, can be performed actively with power consumption or passively without power requirement, depending on the feasibilities of the spacecraft. For 1U-sized CubeSat, passive attitude control system is mostly desirable due to spacecraft's compact form. The 1U CubeSat's properties of limited power supply, small size, and light in weight have been the considerations in selecting the appropriate components for the onboard attitude determination control subsystem (ADCS). This paper presents the preliminary stage of designing the passive ADCS for 1U-sized CubeSat that was implemented through the ASEANSAT Satellite Project. The subsystem involved the selection of different types of magnets that will be used to stabilize the small-typed spacecraft with respect to the Earth's magnetic field. The orientation of the CubeSat in space will be determined by the sensors that were also selected based on the properties of the satellite. Prior to the components' selection, a theoretical calculation for the disturbance torque that involved multiple external factors in space was obtained. The result assisted in determining the permanent magnet and hysteresis rod with appropriate amount of flux density to overcome the effect of disturbance torque on the spacecraft. This paper provides a clear process and guidelines of designing a passive ADCS for 1U CubeSat where the limitations and constraints of the satellite were contemplated.