Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

P (Space and Planetary Sciences ) » P-CG Complex & General

[P-CG25] Planetary Magnetosphere, Ionosphere, and Atmosphere

Tue. May 28, 2019 3:30 PM - 5:00 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Kanako Seki(Graduate School of Science, University of Tokyo), Takeshi Imamura(Graduate School of Frontier Sciences, The University of Tokyo), Hiroyuki Maezawa(Department of Physical Science Osaka Prefecture University), Naoki Terada(Graduate School of Science, Tohoku University)

[PCG25-P02] Developments and performance evaluations of 0.48 THz band heterodyne receivers for the future Mars terahertz sensor missions with micro-satellites

*Ayaka Tomihara1, Satoshi Matsumoto1, Hiroyuki Maezawa1, Yasuko Kasai2, Shigeru Yamada2, Takeshi Kuroda2, Takayoshi Yamada2, Toshiyuki Nishibori3, Yutaka Hasegawa3, Yasumasa Kasaba4, Richard Larsson5, Shinichi Nakasuka6 (1.Osaka Prefecture University, Osaka, Japan, 2.National Institute of Information and Communications Technology (NICT), Tokyo, Japan, 3.Japan Aerospace Exploration Agency, 4.Tohoku University, Tohoku, Japan, 5.Max planck Institute Solar System Research, Göttingen Germany, 6.Tokyo University, Tokyo, Japan)

Keywords:Mars, Planetary atmosphere, Heterodyne remote sensing, Terahertz, Mars lander with Micro-satellite

Mars is an important investigation target for understanding atmospheric environments, habitability, and resources of terrestrial planets. On Mars, methane has been detected, and research continues to study its origin and destruction processes by oxidation reaction networks in the atmosphere and on the surface. In order to understand the evolutionary processes of the Martian atmosphere, detailed and systematic observation of spatial and temporal variation of H2O and oxidants such as HOx, altitude distribution of O2 is still an important subject. Mars will also give us valuable information on the extent to which biomarkers O2 and O3 are formed abiotically in typical earth type planets with mainly CO2 atmospheres.
Therefore, we are developing the Bread Board Model (BBM) of lightweight, low power consumption 0.48 THz band heterodyne remote sensing detectors for future Mars terahertz sensor missions with micro-satellites. THz/submillimeter-wave band heterodyne spectroscopy with high frequency resolution allows us to derive the altitude distribution of trace molecules of the planetary atmosphere, and this frequency band is less affected by the absorption and scattering by aerosol and dust because of its long wavelength. Also, regardless of the presence or absence of background light sources like the sun day- and night-side atmospheres are observable. In the BBM receiver system, subharmonic mixer (SHM) detectors with Schottky barrier diodes operating at room temperature were adopted and a circularly polarized wave separating device was united for the RF input port (manufactured by Virginia Diodes, USA), which enabled us to integrate two SHM detectors flatly and compactly. The equivalent noise temperature of the SHM mixers was 1400 - 1500 K (DSB) in the 1 - 6 GHz band. The power consumption and weight of the mixer receiver system are 11.2 W (1.66 A) and 0.6 kg. In the local oscillator system, 13 GHz band signals from the dielectric resonator oscillator with the phase locked to 99.9 MHz reference signal from an oven controlled crystal oscillator are multiplied and amplified with the integrated amplifier-multiplier chains (IAMC). For temperature fluctuations of about 3.5 degrees at room temperature, the frequency drift in the 0.48 THz band was about 100 kHz. Based on the performance of this front-end system, atmospheric radiative transfer simulation confirmed that atmospheric minor constituents such as O3 and H2O2 as well as O2 and H2O can be sufficiently observed. In this presentation, we will report on these results.