Thermal isolation shields consisting of two glass slides separated by insulating standoffs are positioned upon the front radiation receiving surface of a solar cell and/or upon the back surface of the solar cell. One of the two glass plates is made from material selected to absorb and radiate electromagnetic wave energy with a wavelength above 5 microns to prevent overheating of the cell. The space between the two cover plates forms a thermal gap that is, if desired, bridged by a bimetallic strip. The strip is adhered to one of the plates and has a reverse bend to extend along the face surface of the opposed cover plate. The strip distorts under an increased temperature to break the bridge between the two plates and thereby isolates the solar cell from the thermal shield formed by the outer cover plate until there is a sufficient reduction in temperature at which the bimetallic strip reestablishes conductive contact between the cover plates. Each solar cell assembly in an array is adhered to a substrate by first bonding glass pads to the substrate and then heating the cell and glass pads to a temperature of about 400.degree. while applying an electrical potential of the order of 400 volts with the glass being negative potential with respect to the cell. A hermetic bond is achieved without the use of adhesives.