Concentration of off-axis radiation by solar concentrators for space power

Four types of off-axis radiation are discussed. These are small off-axis angles during walk-off, large off-axis angles, an extended off-axis source such as Earth albedo, and miscellaneous off-axis sources including radiofrequency sources and local point sources. A code name OFFSET has been developed to represent the solar concentrator being developed for Space Station Freedom. It is a detailed ray-tracing model which represents 50 ray-originating points on the Sun and reflections from 10 points on each of the 456 concentrator facets. Results of this code are generally similar to the PIXEL results although there are small differences due to the more detailed representations of the Sun and concentrator that were used in the OFFSET code