For smaller CubeSats ranging from 1U to 3U, power and volume are limited. In this case, a 3-axis magnetorquer based ADCS is recommended. It fits into users’ requirements and delivers enough performance for solar panel pointing & UHF/VHF antenna.
Unlike reaction wheel based ADCS that consumes more power, torquer-based ADCS drives with 3-axis magnetorquers, which is the simplest architecture of ADCS. They generate torque via interacting the torquers’ magnetic field with the earth’s. Detumbling and a rough pointing mode are provided. However, “blind regions” occur while the commanded torque vector is closely vertical to the earth’s magnetic field vector. In these cases, the torquer-based ADCS will have worse pointing accuracy.
To perform the rough pointing functions, GNSS information is required to feed in throughout optional modules or the user’s system. Or, TLE information could work, too. Suppose users’ mission only required simple functions like detumbling without the need for sun acquisition, the fine sun sensors could be taken away.
- Components included: 3-axis magnetorquer*1, FSS100- fine sun sensor*6 (could be removed), MEMS Gyroscope*1, 3-axis magnetometer*1
- Pointing Knowledge: < +/- 0.1 deg @ sun capturable; < +/- 1 deg @ sun is not capturable
- Pointing Accuracy: < +/- 10 deg
- Max. magnetic dipole moment: 0.2 Am^2
- Supply voltage: 3.3V & 5V
- Power consumption: <1W
- Volume: 0.2U
- Mass: < 300 g
- Controlled by the onboard computer (OBC) using I2C or UART with attitude command