[jack_ (OP)]

Mark has a space tech question:

Since satellites are generally made from conductive materials, does their movement through Earth's magnetosphere generate electricity? Could this be used to power them freely and safely. It may require an armature wound with copper wire to make a useful current but it's worth a try.

What do you think, any possibilities here?

[Janus]

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/JZ065i001p00001

A point on your use of "freely".  There is always a cost in generating electricity.  The energy for generating it has to come from somewhere. So even if you could generate usable energy by this method, it would come at the cost of orbital energy of the satellite. 
So whether or not it would be a viable option for a given satellite depends on a couple of factors.
Would this reduce the life of the satellite too much?
How important is it that the satellite maintain a given orbit? ( for example, GPS works because the satellites maintain precise orbits.)

While you could include fuel and boosters to constantly offset the orbital energy loss, how would this effect the launch mass vs. including a different power source?

[evan_au]

This has already been attempted in space - it was one suggestion for de-orbiting old satellites.
See: https://en.wikipedia.org/wiki/Electrodynamic_tether

The same effect also occurs on the Earth's surface during geomagnetic storms - the changing magnetic fields generate low-frequency currents in metal structures like thousands of Amps in the Alaska oil pipeline and overloading transformers in electrical grids.
See: https://en.wikipedia.org/wiki/Geomagnetic_storm#Geomagnetic_storm_effects

[evan_au]

Note that you cannot generate useful electricity from a static potential difference across a wire - you need a voltage and a current to generate electrical power.

So in practice, you need a way to connect the different voltages on your satellite through a low-impedance, non-moving conductive medium (a moving medium would experience the same voltage, and no current would flow).

This means using something like an electrostatic generator to connect the satellite electrically to Earth's thin, ionised outer atmosphere. But an electrostatic generator consumes power, and the near-vacuum of space is not exactly "low impedance".

[syhprum]

It would seem that the subject has been well studied both theoretically and experimentally and it has been found that a small amount of electrical power can be generated from the satellites motion.
Perhaps a new form of perpetual motion machine can be devised by using this power to operate a plasma thrust system !!!!