[PCG25-P05] Radiative Transport Simulations for 0.4 - 1.9 THz Band Heterodyne Spectroscopy of Martian Atmospheric Trace Gases
Keywords:Mars, Planetary Atmosphere, Heterodyne Spectroscpy, Terahertz Remote Sensing
At present, a working group on the Mars Aqueous Environment and Space Climate Orbiter (MACO) project, with an eye to a future small or medium size Mars orbiter satellite, has been formed in Japan. In this study, we also investigated the optimum frequency bands for the THz-band heterodyne spectrometer, which is an optional instrument in this mission plan. The diameter of the antenna is assumed to be 35 cm. The heterodyne detector and spectrometer are assumed to be a Schottky barrier diode (SBD) mixer operated at room temperature and an autocorrelation type digital spectrometer with a bandwidth of 8 GHz and a resolution of 1 MHz, respectively. The shot noise of the SBD mixer detector was taken into account for the spectrum calculations. For example, in 0.9 THz band the emission lines of 13CO, C18O, C17O, H2O, HDO, 18OCO, H2O2, HO2, and O3 can be observed simultaneously by optimizing the frequency setting in double-sideband mode. An altitudinal resolution of better than 6 km will be achieved. When observing high-rise H2O up to around 100 km, it is possible to respond by switching to a dedicated frequency. How limb-sounding data is processed and compressed on board and downlinked is an important future issue.
In this conference, we will present the results of these simulations.