De-tumbling Control of a CubeSat

To keep the proper orientation of the satellite is an essential issue for most space missions. However, tumbling motion of a satellite after separation from the launcher is inevitable and thus the de-tumbling is the first task of the attitude control system of a satellite. Cubesats, one of the nano-class satellites, are defined by Calpoly with masses less than 10kg. A team in National Formosa University is developing a 2-U Cubesat, named as NUTSat, to promote the aviation safety. The cubesat will carry a ADS-B receiver as the main payload to collect the flight information of civil aircraft beneath the orbit. An attitude control system of the cubesat is designed to perform the detumbling and attitude control and keep the ADS-B antenna towards to the earth. The cubesat has two magnetic torquers and one coil to interact with the earth's magnetic field to generate proper torques to change the attitude. A three-axis magnetic sensor is used to estimate the satellite's orientation. At this phase, the de-tumbling has been validated by simulation. Further attitude pointing controller design is undergoing.