Comparison of Atmospheric Mass Density Models Using a New Data Source: COSMIC Satellite Ephemerides

Atmospheric mass density (AMD) plays a vital role in the drag calculation for space objects in low-Earth orbit. Many empirical AMD models have been developed and used for orbit prediction (OP) and efforts continue to improve their accuracy in forecasting high-altitude atmospheric conditions. Previous studies have assessed these models at the height of 200 km to 600 km. In this article, four state-of-the-art AMD models, i.e., Mass Spectrometer Incoherent Scatter extended model (MSISE90), MSISE00, Jacchia–Bowman 2008, and Drag Temperature Model 2013 are assessed for their OP capabilities by using a new data source of Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellite ephemerides at an orbital height of $\sim$800 km, where the contribution of ions in the total AMD is more significant. A new testing model was developed by accounting for ion contribution based on the International Reference Ionosphere 2016 model, including many more ion species that are not accounted for in other AMD models. In the assessment, two periods of forty days were chosen in 2014–2015 and 2018–2019, representing solar maximum and minimum periods, respectively, to assess four existing AMD models and the proposed model. Thorough analyses were conducted to compare OP results using different AMD models with precise reference ephemerides of COSMIC satellites and based on various space weather indices. It is shown that the proposed model outperforms all other AMD models in terms of OP errors during the solar maximum period. During solar minimum, the drag acceleration is relatively small for COSMIC satellites. Assessment of all AMD models in the OP process tends to be contaminated by the remaining uncertainty sources, such as solar radiation pressure.