Using Real Earth Albedo and Earth IR Flux for Spacecraft Thermal Analysis



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47th International Conference on Environmental Systems


For the last twenty years, Earth observation instruments have been providing invaluable data about Earth radiated energy measured from Space with an increased accuracy and a continuous improved Earth surface coverage. NASA’s CERES experiment has been designed to measure both solar-reflected and Earth-emitted radiation from the top of the atmosphere to the Earth's surface. It currently encompasses 3 similar instruments on board of 3 different Earth observation satellites (Terra since 1999, Aqua since 2002 and Suomi-NPP since 2011). CERES measurements provide essential data to improve our understanding of the Earth's total climate system and climate prediction models. But the accumulation of global and daily Earth radiated energy data is also of a great interest for thermal engineers designing and modelling Earth orbit spacecraft. Some standards have defined for a long time Earth thermal environment for spacecraft thermal analysis. It’s nevertheless a bit hard to keep a track of their origins with the passing years and the way various projects have used them seems coherent but with more or less variations. The objective of this paper is to recreate a link between real observations and Earth environment assumptions used for Earth orbiting spacecraft thermal analysis, by comparing the common Earth albedo and Earth Infrared flux hypotheses with the real measured Earth radiated energy. From such comparison, one should assess if the current hypotheses cover properly the reality or how to quantify the margin potentially contained in these usual assumptions. As an ultimate goal, this paper aims at evaluating if the usual hypotheses need to be updated. In parallel, this paper will present an assessment of typical spacecraft sensitivity to Earth environment depending on several parameters (linked to the spacecraft or to the Earth) to properly evaluate how much it is worth considering revising Earth environment assumptions.


Romain Peyrou-Lauga, European Space Agency (ESA), Netherlands
ICES207: Thermal and Environmental Control Engineering Analysis and Software
The 47th International Conference on Environmental Systems was held in Charleston, South Carolina, USA on 16 July 2017 through 20 July 2017.


Albedo, Infrared flux, Earth, Thermal analysis