A modular construction system that can be used to construct a variety of structural units including armor shields for vehicles or personnel, energy generating grids, thermal insulating or transmitting structures, acoustic insulating or reflecting structures, electromagnetic shields, etc. The modular construction system uses modular discs which are configured to be coupled or connected together to form or develop any desired structure. The modular discs include substantially circular base portions, star-shaped projections extending from the upper surface of the substantially circular base portion, and cooperating connecting structures that allow for the plurality of modular discs to be connected to one another.