1. Scope 1.1 These tables define the solar constant and zero air mass solar spectral irradiance for use in thermal analysis, thermal balance testing, and other tests of spacecraft and spacecraft components and materials. Typical applications include the calculation of solar absorptance from spectral reflectance data and the specification of solar UV exposure of materials during simulated space radiation testing. 1.2 These tables are based upon data from experimental measurements made from high-altitude aircraft, spacecraft, and the earths surface and from solar spectral irradiance models. 1.3 The values stated in SI units are to be regarded as standard. Other units of measurement are included for information purposes only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.