HOW THE ELECTROMAGNETIC THRUSTER WORKS

               HOW THE ELECTROMAGNETIC SPACECRAFT THRUSTER WORKS

     I have gotten to the point where I have a somewhat working model of an electromagnetic propulsion device that would work in low Earth orbit, at least in theory.

     It is easy to see how the magnet turns to align with Earth’s north and south magnetic poles just like a compass and than how an electromagnet by changing its polarity is made to rotate in a circle like a motor. We saw how adding a fin to push against the water made my model move in a line through the water. We have farther more seen that we can accomplish the translation from rotation to linear motion by placing a weight on our model.

     This may seem a little mysterious so what are the actual mechanics of an electromagnet rotating in Earth’s magnetic field like a motor translating to linear motion?

     I have given this a considerable amount of thought and I truly believe this is the easiest to grasp explanation I can currently provide:

     The torque from the electromagnet interacting with Earth’s magnetic field is applied at one point on the device. That is the force of rotation provided by the electromagnet.

     The device has a tendency to rotate around its center of mass, which is at a different point. I am not sure what physical law states that is so but it seems self evident.

     Since there are two points where rotation is ‘trying’ to take place the actual rotation occurs at a third point. Again this is a little intuitive but shouldn’t be hard to grasp.

     So when the device rotates around the third point, which is not the center of mass, the heavier or more massive portion of it moves in an arc. This is also intuitive since if the center of rotation is not at the center of mass one side or the other of that mass must be greater.

     That portion of the device with the more mass pulls the whole device with it as it rotates. This is from centrifugal force or you may want to think of it in terms of movement and momentum. (Physicists say there is really no such thing as centrifugal force, but that is beside the point.)

  

                                   MORE TO CONSIDER ON PRACTICALITY

     To use this as it now is in concept would require the spacecraft to mostly consist of the electromagnets and also that the whole spacecraft would need to rotate. Here the concept is only in its baby stages and might be developed to the point where it could rotate on an axle that would then be attached to the spacecraft.

     Also does the device only have the capacity to go in one direction? That is something to consider.
Actually I have some ideas on this some of which I have already tried out.

     The first way to control the direction of linear motion is to control the direction of rotation. The opposite direction of rotation will make it go in a different direction. Next the direction may be affected by changing the timing of the reversal of polarity of the electromagnets. I have done some experiments and this seems to be the case. Also, the position of the secondary electromagnets would alter the direction of linear rotation.
 
     Of course it can go in any direction along the plane parallel to the lines of Earth's Flux if it instead of rotating swings side to side like a pendulum.


Here is a diagram:

Centrifugal Force and Propulsion When an External Force Moves the Pendulum

         Centrifugal Force and Propulsion When an External Force Moves the Pendulum          

     Inertial propulsion systems in various forms such as with gyroscopes or pendulums that swing in smaller arcs at one end of a circle than at the other don't work. At least none has ever been demonstrated to work.

     That being said there is still a way they can be used as long as the force driving the pendulum is external to the pendulum system.

     In this case I used the Earth's magnetic field.

     To understand this we will imagine a pendulum and 4 rocket thrusters floating in micro gravity. Imagine there are two thrusters close together on each side of the arm of our pendulum near the end opposite the weight. Those thrusters would then be imagined to go on and off in such a way that they would swing the pendulum back and forth. While the pivot point of the pendulum where the thrusters were would not stay still there would be a sort of overall cycling swing of the pendulum in our micro gravity. The thrusters observe Newtons law of action and reaction.

    The swinging of the pendulum would create centrifugal force in only one direction and cause the model to accelerate in that direction.

     Now let's apply this to Earths magnetic field and electromagnets acting similar to a compass.
The electromagnets make the pendulum swing side to side but also observe Newtons law. The force of Earth's magnetic field interacting with the electromagnets makes the pendulum swing in a way that we would not consider unusual.
 
     As the pendulum swings the centrifugal force pulls it in one direction just as with the thrusters.
There is no magic here.

    So in the below video my model is floating in water to simulate low gravity and friction. The electromagnets are at right angles to each other and swing the model side to side.

   
     My model may look like a bunch of wires and stuff on some styrofoam discs but actually is pretty simple. It consists of some homemade electromagnets, batteries and an Arduino. There is an IR TV remote control circuit to turn the power on so that the model can settle still before starting when the button is pressed. The Arduino is programmed to turn the electromagnets on alternating so that the model generally swings side to side as the electromagnets at right angles to each other each align north and south with Earth's magnetic poles like a compass.

Earliest occurance of this concept in my mind.

     At least 10 or 20 years ago I believed it would be possible for a combination of an electromagnet and a gyroscope to affect navigational changes on a spacecraft in low Earth orbit.
     My concept of the forces was that the overall force of such a device would be limited and of course not be anywhere near as powerful as a chemical rocket motor.

     About in 2015 when Neodymium magnets were getting to be very popular I decided to give it a try. I had some limited results and didn't really understand why it worked.

    The original model was made of Lego's with a simple rotor that had some magnets on one side and some solder on the other side to balance it. Since then I learned that most of what appeared to be working was from "Slip Stick Effect". That is how those little HexBug Nano things work. Basically if you have oscillation and friction it will make something move. It would work in water or on a surface but not in space at all. Since my experiments were on water it was obvious more study was needed.
 
    Also it was necessary to simplify things so I put a little HexBug Spider robot with an IR Remote on a Styrofoam disc of about 8 inch diameter. I taped the magnets to the robot's head, which rotated side to side and I attached a fin to the Styrofoam disc.

 
    Sure enough that simple demonstration worked. As I turned the robot's head from side to side the Styrofoam disc on which it was floating in a container of water rotated so that the magnets would align north and south. That pushed the fin in the water from side to side and the little contraption made its way from one end of the water container to the other.
 
    Now I had my arms around the concept that the rotation created by a magnet in Earth's magnetic field could be strong enough to move a small "boat".

     I stayed with the notion of the rotation or torque of the magnet in Earth's field and sought to understand how it could be translated into linear motion without actually pushing in the water.

    Here is the video of one of those early experiments using a weight instead of a fin:

    https://youtu.be/LFlmEjj2jmo

 
    It can also be found on my Youtube channel:
https://www.youtube.com/channel/UCyGGu_mvODGRjCdhbGc0Y9g?view_as=subscriber