# Could a CubeSat be propelled by this low-tech electromagnetic propulsion system?

I have come up with a conceptual idea for a low-tech electromagnetic propulsion system for a CubeSat, and I would like to know if it would create (on a theoretical basis) a net force strong enough to keep a CubeSat in orbit and/or propel it through interplanetary space.

Please reference the conceptual drawing below.

This is showing a non-metallic board with two non-metallic posts fastened to it. Attached to each post is a non-metallic lever with an electromagnet fastened to each end of the lever. (The wires for each electromagnetic are not shown on this drawing). I have labeled each electromagnet with a number to help explain how the system would work. The arrows on the drawing indicate the rotational direction of each lever.

The working principle is that as an electromagnet on each lever is pulled towards each other via their interacting magnetic fields, each lever will be pulled away from the post that it is pivoting on, and this pulling force being exerted on each post will create a net force on the board that should propel the board (and thus the CubeSat) in the direction indicated on the drawing.

The way it would work is as the levers rotate around their posts, when the electromagnet on the top lever reaches Point B and the electromagnet on the bottom lever reaches Point C, electricity will be supplied to these electromagnets causing them to attract one another. When both of these electromagnets reach Point A together, then the electricity to each of these will be turned off so the two will not be magnetically locked together and cause their levers' rotation to stop. Rotation-activated electrical switches would perform this function.

So, as electromagnets #2 and #3 are turned on while they travel between Points B/C to Point A, electromagnets #1 and #4 will be turned off. Then when electromagnets #1 and #4 are turned on while traveling between Points B/C to Point A, electromagnets #2 and #3 are turned off. The electricity for the electromagnets would come from batteries charged up by solar panels.

Also, I believe that the levers should rotate around high-friction shaft bearings. These would be ideal for this system because the harder it is for the electromagnets to rotate the levers, the longer the levers will be in the Points B/C to Point A area of the board and should thus generate more net force during each full revolution of the levers, yet I don't know if this would be true or not. The trade off with using high-friction shaft bearings is that a lot of heat would be generated.

Would this low-tech electromagnetic propulsion system actually work and would the net force created be enough to keep a CubeSat in orbit and/or propel it through interplanetary space?

• All the forces will sum to zero. Commented Jul 9, 2019 at 20:14
• You might want to take a look at this: en.wikipedia.org/wiki/Space_tether Commented Jul 10, 2019 at 11:13
• Are you expecting the device to propel itself by reacting against an external field (as in the answer that was posted) or simply by pushing on the posts (my interpretation)? In other words, if this device was in space, far enough from any star or planet that there was no external fields affecting it - a conceptual perfect absence of external influences-, do you think it would work? Commented Jul 10, 2019 at 12:31
• @ Organic Marble, yes, I believe that if this device was in space far from any star or planet, it would produce motion via the influence of the external field, which would be the electromagnets' magnetic fields, acting against the magnetic fields being produced within the copper plate(s) via eddy currents (i.e. an application of Lenz's Law).
– user28781
Commented Jul 10, 2019 at 13:22
• If it's not reacting against some external field, then it's a reactionless drive, and can't work because of conservation of momentum. askamathematician.com/2017/12/… Diving into the details isn't necessary! Reactionless drives can't work. Commented Jul 10, 2019 at 13:39

## 1 Answer

Could a CubeSat be propelled by this electromagnetic propellantless propulsion system?

No, I'm pretty sure it can't, unless it is very large (kilometers or larger).

Because permanent magnets and electromagnets only provide dipole and higher magnetic moments, there is no way to propel yourself in a uniform magnetic field. You need monopoles to do that.

The electric analog is the same; put an electrostatic dipole in a uniform electric field, and it will feel a torque, but no net force.

However, if your system is very large, say kilometers or more, you might be able to use the very weak gradient in the Earth's field to gain a very tiny amount of forward or backwards propulsive force, though I'm not sure.

• that is interesting. Perhaps this may be an ideal propulsion system for use in man-made satellites that will one day orbit around Jupiter since its magnetic field is some 20,000 times stronger than Earth's magnetic field.
– user28781
Commented Jul 9, 2019 at 23:32
• @HRIATEXP Wikipedia says only 14 times stronger, and because of the larger size, the gradient will not be much stronger than that of Earth.
– uhoh
Commented Jul 9, 2019 at 23:35
• my bad, the source I had found on Google is comparing Jupiter's Magnetosphere to Earth's Magnetosphere, see lasp.colorado.edu/outerplanets/giantplanets_magnetospheres.php
– user28781
Commented Jul 9, 2019 at 23:38
• @HRIATEXP hey that is interesting! I would recommend you ask a new question, something like "If Jupiter's magnetic field is 14x stronger than Earth's, why is it's magnetosphere 20,000x stronger?" and quote "Some 20,000 times stronger than Earth's magnetic field, Jupiter's magnetic field creates a magnetosphere so large it begins to avert the solar wind almost 3 million kilometers before it reaches Jupiter." This is a real puzzle! Include both that link and the Wikipedia link (and quote).
– uhoh
Commented Jul 9, 2019 at 23:46
• I think I will ask that question tomorrow.
– user28781
Commented Jul 10, 2019 at 0:14