Cheng-Li Huang
Biography & lecture abstract
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Lecture: Contribution of Yinghuo-1 to the Martian gravity field model
There are several models of the Mars gravity field published, mostly from the Doppler tracking data of the Mars Global Surveyor (MGS) spacecraft and partly from other spacecrafts in orbit around Mars such as Mars Odyssey, MRO, and MEX, as well as in the early stages of a mission (Viking series). Unfortunately, most of these satellites have near-polar orbits, and due to the shortage of methods commonly used in the calculation of spherical harmonic coefficients, these spherical harmonic coefficients of the gravity model derived from these similar orbits data will suffer, more or less, from the so-called "lumped" phenomenon, i.e., the lower-degree even/odd zonal coefficients contain the influence of higher-degree even/odd zonals. The Chinese-Russian collaborated Mars mission will be launched in November 2011. On the Chinese side, the satellite Yinghuo-1 (YH-1), will orbit Mars for about 1 year. Thanks to the special characteristic of the YH-1 orbit, especially its low inclination, one can expect its radio tracking data to contribute to the study of the Martian gravity field. In this study, the radio tracking data of YH-1 is simulated. After integrating with other available Doppler tracking data, mostly from MGS, we try to analyse how the YH-1 data help to improve the Mars gravity field, especially on the low latitude band, in which most of the large scale topographic characteristic are located. Moreover, the possibility of a YH-1 flyby of the two natural satellites of Mars, Phobos and Deimos, and the scientific value of studying the physics of Phobos and Deimos will be also discussed.