The TacSat-4 spacecraft carries a solar cell experiment characterizing a string of 3 triple-junction 1-sun solar cells and a string of triple junction solar cells under a flexible, linear Fresnel lens providing approximately 6 times solar concentration. TacSat-4 flies in a highly elliptical, four hour orbit, passing through proton and electron radiation belts 12 times per day. The damage to solar cells in this environment is severe. In this paper we examine the solar cell damage rates of the two solar cell strings.