Investigating scale factors of radiation pressure accelerations of SLR satellites
Authors: Vielberg Kristin , Löcher Anno , Kusche Jürgen 
Published: March 2021

&lt;p&gt;&lt;span&gt;&lt;span&gt;For low Earth orbit satellites, the atmospheric drag is the largest non-gravitational force. With increasing satellite altitude, the acceleration due to the Earth radiation pressure &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;(ERP) &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;decreases, &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;whereas the effect of the Solar radiation pressure &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;(SRP) &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;becomes prevalent. &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Models of these &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;non-gravitat&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;io&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;nal forces are &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;applied in satellite gravimetry, thermospheric density estimation, and&lt;/span&gt;&lt;/span&gt;&lt;span&gt; &lt;/span&gt;&lt;span&gt;&lt;span&gt;in&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; precise orbit estimation of the spherical satellite laser ranging (SLR) satellites. &lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;&lt;span&gt;In earlier investigations, we found that &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;estim&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;ating &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;systematic errors in radiation pressure &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;force &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;models &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;appears possible based on an inverse procedure using GRACE data. &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Our preliminary results show that &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;the &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;outgoing radiation from CERES SYN data is too small for both longwave and shortwave &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;data&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;. &lt;/span&gt;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;&lt;span&gt;Here, we want to test the suitability of another approach to obtain estimates for correcting &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;existing&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; radiation data. In this method, &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;we &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;focus &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;on the estimation of sca&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;le&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; factors for radiation pressure accelerations &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;of &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;different &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;SLR satellites &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;with the long-term aim to obtain corrections for existing radiation datasets&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;. &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;D&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;uring &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;the precise orbit determination &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;procedure &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;of the sph&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;e&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;rical SLR satellites, &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;t&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;he scale factors are &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;commonly estimated with a vari&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;e&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;ty of other param&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;e&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;ters&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;.&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; Here&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;, we test different parametrizations of the scale factors of both ERP and SRP accelerations and their behaviour for different SLR satellites such as &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Stella and Ajisai &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;during varying solar conditions&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;. &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Besides the separate estimation of scale factors for ERP and SRP accelerations, we will estimate&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; global (monthly) scale factor&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;s&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; for ERP &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;accelerations &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;from &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;a variety of &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;SLR &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;satellites. &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;Finally, &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;we will investigate &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;the &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;potential&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; of &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;the resulting &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;scale &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;factors&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; to correct existing radiation datasets &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;in the future.&lt;/span&gt;&lt;/span&gt;&lt;span&gt; &lt;/span&gt;&lt;span&gt;&lt;span&gt;At this stage, a comparison to our preliminary estimates &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;from &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;our previous investigations &lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt;turns out as&lt;/span&gt;&lt;/span&gt;&lt;span&gt;&lt;span&gt; helpful.&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;