Magnetic disturbances in attitude model

[Mr-Medina]

Feature

Related to issue #180 and #193. Satellites can have a residual magnetic dipole resulting in attitude disturbances depending on their orientation to to the Earth magnetic field. Need to addd external torques from the Earth magnetic field to a magnetically charged actor.

Desired Behavior / Functionality

User defines actor's magnetic charge modelled as a dipole. Attitude model compares the actor dipole orientation with the magnetic field vector of the Earth and provides angular acceleration.

What Needs to Be Done

1. Model the Earth magnetic dipole at correct offset from the Earth rotational axis at the correct date & time.
2. Find the relative directions of the Earth field and actor dipole vectors
3. Calculate the resulting torque
4. Test the resulting angular acceleration and rotation of the actor

How Can It Be Tested

Put the actor in a symmetrical state (w.r.t. Earth field lines) and check if it follows the magnetic field lines.