Preliminarily study of Saturn’s upper atmosphere density by observing Cassini plunging via China’s deep space station

Abstract

Abstract When the Cassini spacecraft finally plunged into the Saturnian atmosphere on 2017 September 15, China’s deep space telescope pointed to Saturn to observe Cassini and study the Saturnian upper neutral atmosphere. In this first Chinese Saturnian radio science experiment, X band Doppler velocity radio science data between the deep space telescope and the Cassini spacecraft were obtained. After removing Saturnian and solar gravity effects, Earth rotation effect, the remaining Saturnian atmosphere drag information was retrieved in the Cassini final plunge progress. Saturn’s upper neutral atmosphere mass density profile is approximately estimated based on atmosphere mass density derived principally by real orbit measurement data. Saturn’s upper neutral atmospheremass density from76 000 km to 1400 km is estimated fromthe orbit measurement data, the mass density results are about from 1.4 × 10−15 kg cm−3 to 2.5 × 10−14 kg cm−3.