Photovoltaic power system operation in the Mars environment

Variation of solar insolation (global, direct and diffuse) at the Viking Lander locations is described. The radiation data are based on measured optical depth of the Martian atmosphere derived from images taken of the Sun, through the atmosphere, with a special diode on the Viking cameras and on computations based on multiple wavelength and multiple scattering of the solar radiation. The data are used to estimate photovoltaic system power, area and mass for a surface power system using regenerative fuel cells for storage and night-time operation