Verification of Multi-Utility Spacecraft Charging Analysis Tool (MUSCAT) Via Laboratory Test

Abstract

Multi-utility Spacecraft Charging Analysis Tool (MUSCAT), a spacecraft charging analysis software, has been developed as a joint work of JAXA and KIT. Experiments for the fundamental code validation were carried out at the plasma chamber of LaSEINE in KIT to show accuracy of the solver. We evaluated that the test section in the chamber with respect to the plasma environment by measuring two-dimensional plasma distribution and plasma drift velocity. A cube area of 400mm on a side whose center located at the 550mm downstream from plasma source can be considered as the test section with no plasma flow. The averaged plasma density, temperature and plasma potential within this test section were 3±2x10 12 m -3 , 2±1eV and 10±5V, respectively. The length of test section 400mm corresponds to about 67λ D . Spatial distribution of electric potential and IV characteristic curve were measured with an emissive probe and the Langmuir probe whose electrode were cubic in shape to adjust the rectangular numerical domain of MUSCAT. Comparing those experimental results with the numerical ones, both had good agreements. These results show that the physical functions of MUSCAT simulate charging processes quite well. Also, numerical model of the cell-side of solar array paddle was obtained. Conductor patches whose size is the quarter of total amount of the interconnector exposed area put on the coverglass can simulate the cell-side of a real solar array with respect to current collection.