99 Years Later... We Solved It

These are prototypes made by Tesla and SpaceX.  Self driving stones that run on hydrogen extracted from the top layer of dirt.  The high content of salt results in a hard surface where the particles  in the top layer stays at the top for extended periods of time allowing solar radiation to work its magic.   The same is happening on the moon with the regolith.  
The concentration of hydrogen is naturally much higher at the moon since there is no magnetic field or atmosphere to keep the high powered radiation from slamming inn to the particles of the top layer.   This is why the self driving rocks are  very very slow.   There is not enough hydrogen to make them go any faster.    
A solar panel the same size as the surface area of the rock would deliver around a million times more power, but for this project it was not needed and would only increase cost and complexity.   Its neat way to power an experiment, but in the end that is all it is.   Just another one of Elon Musks projects .. impossible or not, they have a way of becoming real.