The worst-case thermal environment parameters of small satellites based on Real-Observation Data

Abstract

The thermal environmental conditions that define the worst-case analyses of Low Earth Orbit (LEO) satellites have been selected based on the Criteria established by National Aeronautics and Space Administration (NASA) in 1994 using first Earth Radiation Budget Experiment (ERBE) data about the Radiative Energy Budget. Even if this methodology has been widely used in space missions, no review has yet been made with the new available and more precise data. Particularizing this analysis to small satellites (CubeSat, NanoSatellites, Picosatellites) the in-orbit albedo and Outgoing Longwave Radiation (OLR) variations, together with the direct Solar radiation, drive the thermal behavior of the systems. In contrast to bigger satellites, which are mainly affected by the average heat flux over their surfaces, small satellite temperatures are considerably coupled to the in-orbit variations caused by local variations in the atmosphere radiative characteristics. In order to understand all factors that take part in the thermal environment characterization of a LEO orbit, a deep study of the sampled Clouds and the Earth's Radiant Energy System (CERES) albedo and OLR time-series obtained from a satellite propagator has been performed. These time-series have been also analyzed in order to obtain the worst-case albedo and OLR profiles that maximize and minimize the temperatures in the orbit. The recommended European Space Agency (ESA) software for thermal analyses, ESATAN-TMS, is usually used for constant albedo and OLR analyses but it can be configured for allowing time-dependent profiles.