that was mostly done by Hasely and a lot was lost when chie-chiety (i think that was the planet) fell they lost a lot of research data. also the shields used by ships (large shields), doors, and the bubble shield is different than the personal shields of spartans and elites. the personal shield repells all objects and can have varying thickness (strength is better the thicker it is). It repels everything even the wepons they hold, but they have tuned down the power to the hands to make the shield so thin it does not effect handling.