I want to select actuators for a micro-satellite (around 40 kg) orbiting in LEO.
I proceeded in calculating the maximum disturbance torques that affect my spacecraft and selecting proper reaction wheels for three axis stabilization.
Now I want to select a second set of actuators, to activate them during the desaturation of the wheels and I choose a magnetic torquer (since it'll be in LEO and I want to minimize the mass of the fuel). The problem is that I can't find an appropriate explanation about how to select a magnetic torquer for this purpose.
I didn't quite understand if:
- Does the magnetic torquer desaturate the wheel?
- Is the motor that resets the speed of the wheel and the magnetic torquer counteract the unwanted rotation of the spacecraft due to the spin down of the wheel?
If the right answer is the first one, I don't understand essentially how it works and if the right answer is the second one (the one that I suppose it to be), I don't understand how to take into account the torque that generate the wheel during the desaturation to select the magnetic torquer.
I hope that my question is well asked and I want to thank in advance those who will answer me.