Is it feasible to create a strong dynamic dipole inside a satellite so that it can be rotated on its axes and even possibly pushed in a direction due to the Earth's Normal Electric field. This might be a very slow process, but considering it requires only electric power and no propulsion, could this be a probable technique?


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  • $\begingroup$ See en.wikipedia.org/wiki/Electrodynamic_tether $\endgroup$ – PM 2Ring Sep 9 at 19:30
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    $\begingroup$ Yes, Magnetorquers are used on CubeSats for this purpose. Also, this may be better on the Space Exploration site... $\endgroup$ – astrosnapper Sep 9 at 19:40
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    $\begingroup$ I think the magnetic field would be more realistic. $\endgroup$ – peterh Sep 9 at 20:58

This is an interesting idea, and could potentially be useful for an ultra-low power application.

Conventional magnetorquers require a constant supply of electrical current running through resistive copper coils in order to produce a torque using Earth's magnetic field. Since the Earth's magnetic field has a lumpy, offset and tilted dipole shape you need to know where you are with respect to the field in order to constantly recalculate the required current in your three axis coils in order to optimize your attitude control. (If you are only doing momentum unloading, you can be less precise)

If you can afford the electrical current to run the coils, then it's fine. But if you wanted a very low power attitude control system, an electrostatic charge distribution can be established with only a tranisent in current, plus a low level maintenance current to offset leakage as well as charging effects from charged particles trapped in Earth's magnetic field.

Your spacecraft's electrostatic field would then produce a torque depending on the orientation with respect to Earth's electrostatic field.

However, I am not sure if in a space environment the Earth's electrostatic field is as well behaved as you think it might be. It's probably going to be constantly messed up by space weather.

For an alternative low-power source of torque, I'd recommend you use an articulated permanent magnet. Have a small but powerful rare-earth permanent magnet on a 2-axis gimbal, and use very low power motors to move it around so that you generate magnetic torque without having to dissipate power in copper coils. For more on that, see Could an articulated permanent magnet work as a low-power cubesat magnetotorquer? Problems?.

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    $\begingroup$ As noted by astrosnapper in a comment to the question (back in the astronomy community?), magnetorquers have been used on CubeSats. I've been told they are used to detumble a CubeSat over a couple of orbits. But for actual orientation after that, reaction wheels are generally employed. $\endgroup$ – Rick 0xfff Sep 12 at 1:09
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    $\begingroup$ @Rick0xfff Generally yes, but I can imagine the possibility of wanting to desing a budget cubesat that only has magnetotorquers for budgetary or mass or simplicity of design considerations; so I've just asked Are there any modern cubesats or smallsats that have relied only on magnetotorquers for attitude control? $\endgroup$ – uhoh Sep 12 at 2:25

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