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All were circular orbits of radius 7178 kilometers. Twenty three satellites with different inclinations and equator crossings were simulated, allowing the results of thousand of multisatellite sets to be intercompared. A diurnal oscillation was also included in the emitted flux and albedo to give a source field as realistic as possible. These were chosen on the basis of a simulation of flat plate and spherical detectors flying over a daily varying earth radiation field as measured by the Nimbus 3 medium resolution scanners. The best set of the two were satellites at orbit inclinations of 80 deg and 50 deg of three the inclinations were 80 deg, 60 deg and 50 deg. The optimum set of orbit inclinations for the measurement of the earth radiation budget from spacially integrating sensor systems was estimated for two and three satellite systems. Optimum satellite orbits for accurate measurement of the earth's radiation budget, summary We also discuss the limitations of SPENVIS simulations, particularly outside the Earth’s trapped radiation and point to new resources attempting to address those limitations. We summarize how different orbits change the charged particle background and the radiation damage to the instrument. We present simulations from ESA’s SPace ENVironment Information System (SPENVIS) of the radiation environment for spacecraft in a variety of orbits, from Low Earth Orbit (LEO) at multiple inclinations to High Earth Orbit (HEO) to Earth-Sun L2 orbit. All existing and proposed missions have had to make choices about orbit selection, trading off the radiation environment against other factors. The scientific utility of any space-based observatory can be limited by the on- orbit charged particle background and the radiation-induced damage. The impact of different albedo and emission models as well as the macro model and the altitude of satellites on ERP accelerations will be discussed.īackgrounds, radiation damage, and spacecraft orbits Albedo and emission models are generated as latitude-dependent, as well as in terms of spherical harmonics. As input fields, monthly 1°x1° products of Clouds and the Earth's Radiant En- ergy System (CERES), 元 are considered. In this sensitivity study, we assess ERP accelerations based on different input albedo and emission fields and their modelling for the satellite missions Challenging Mini-Satellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE). Estimating acceler- ations requires knowledge about energy emitted from the Earth, which can be derived from satellite remote sensing data, and also by considering the shape and surface material of a satellite.

The influence of ERP increases with decreasing distance to the Earth, and for low- earth orbit (LEO) satellites ERP must be taken into account in orbit and gravity computations. Earth also emits and reflects the sunlight back into space, where it acts on satellites. The sun radiates visible and infrared light reaching the satellite directly, which causes the SRP. The main non-gravitational forces besides thermospheric drag, acting on the surface of satellites, are accelerations due to the Earth and Solar Radiation Pres- sure (SRP and ERP, respectively). The orbits of satellites are influenced by several external forces. Vielberg, Kristin Forootan, Ehsan Lück, Christina Kusche, Jürgen Börger, Klaus

Assessing the Impact of Earth Radiation Pressure Acceleration on Low- Earth Orbit Satellites