power of a passive daytime radiative cooling surface has been estimated at ~100-150 W/m2. Space Insolation is the primary variable affecting equilibrium temperature in spacecraft design and planetology. Solar activity and irradiance measurement is a concern for space travel. For example, the American space agency, NASA, launched its Solar Radiation and Climate Experiment (SORCE) satellite with Solar Irradiance Monitors. See also Earth's energy budget PI curve (photosynthesis-irradiance curve) Irradiance Albedo Flux Power density Sun chart Sunlight Sunshine duration List of cities by sunshine duration References Bibliography External links Global Solar Atlas - browse or download maps and GIS data layers (global or per country) of the long-term averages of solar irradiation data (published by the World Bank, provided by Solargis)] Solcast - solar irradiance data updated every 10–15 minutes. Recent, live, historical and forecast, free for public research use Recent Total Solar Irradiance data updated every Monday San Francisco Solar Map European Commission- Interactive Maps Yesterday's Australian Solar Radiation Map Solar Radiation using Google Maps SMARTS, software to compute solar insolation of each date/location of earth NASA Surface meteorology and Solar Energy insol: R package for insolation on complex terrain Online insolation calculator Atmospheric radiation Solar System Solar phenomena