First Results of Mars Express—ExoMars Trace Gas Orbiter Mutual Radio Occultation
Cardesín-Moinelo, Alejandro; Wilson, Colin; Witasse, Olivier; Sánchez-Cano, Beatriz; Müller-Wodarg, Ingo; Geiger, Bernhard; Svedhem, Hâkan; Parrott, Jacob; Schmitz, Peter; Godfrey, James; Reboud, Olivier; Nava, Bruno; Migoya-Orué, Yenca
United Kingdom, Netherlands, Spain, Portugal, Germany, Italy
Abstract
Spacecraft-to-spacecraft radio occultations experiments are being conducted at Mars between Mars Express (MEX) and Trace Gas Orbiter (TGO), the first ever extensive inter-spacecraft occultations at a planet other than Earth. Here we present results from the first 83 such occultations, conducted between 2 Nov 2020 and 5th of July 2023. Of these, 44 observations have to-date resulted in the extraction of vertical electron density profiles. These observations are the successful results of a major feasibility study conducted by the European Space Agency to use pre-existing relay communication equipment for radio science purposes. Mutual radio occultations have numerous advantages over traditional spacecraft-to-ground station occultations. In this work, we demonstrate how raw data are transformed into electron density values and validated with models and other instruments.