Detailed information on solar radiation characteristics on Mars are necessary for effective design of future planned solar energy systems operating on the surface of Mars. In this paper we present a procedure and solar radiation related data from which the daily variation of the global, direct beam, and diffuse insolation on Mars are calculated. Given the optical depth of the Mars atmosphere, the global radiation is calculated from the normalized net flux function based on multiple wavelength and multiple scattering of the solar radiation. The direct beam was derived from the optical depth using Beer's law, and the diffuse component was obtained from the difference of the global and the direct beam radiation. The optical depths of the Mars atmosphere were derived from images taken of the Sun with a special diode on the cameras used on the two Viking Landers.