An environmental test chamber providing acceleration of uv radiation and precise temperature control (+- 1/sup 0/C) has been designed, constructed and tested. This chamber allows acceleration of solar ultraviolet up to 30 suns while maintaining temperature of the absorbing surface at 30/sup 0/C to 60/sup 0/C). This test chamber utilizes a filtered medium pressure mercury arc as the source of radiation, and a combination of selenium radiometer and silicon radiometer to monitor solar ultraviolet (295 to 340 nm) and total radiant power output, respectively. Details of design and construction and operational procedures are presented along with typical test data. The test chamber was designed for accelerated testing of solar cell modules.