ASTM E490-22

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, the specification of solar UV exposure of materials during simulated space radiation testing, and the rating of photovoltaic cells deployed in space.

1.2''These tables are based upon data from experimental measurements made mostly from spacecraft, with minor contributions from observations made on high-altitude aircraft, or from the earth's surface.

1.3''These tables are representative of periods when the sun'''s activity is average or moderate. The sun'''s activity tends to modify its spectrum almost exclusively in the UV and extreme UV spectral regions (below 0.1'''''m).

1.4''Units'''The values stated in SI units are to be regarded as standard. Other units of measurement are included for information purposes only.

1.5''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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.6''This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.