[PPS05-P01] New thermal infrared camera for fine horizontal brightness temperature structures at the cloud-top level of Venus
Keywords:Venus, atmosphere, Akatsuki
We propose that a future Venus orbiter carries an updated version of the uncooled microbolometer camera (BOL) with 1024x768 pixels and angular resolution of ~0.01 deg/pixel to detect fine temperature structure on the cloud-tops. When the orbiter is typically injected to a high-inclined elliptical orbit with altitude of 500-50,000 km, BOL provides a spatial resolution of 8.5 km at apoapsis and 0.08 km at periapsis, respectively. It will be enough to observe the fine temperature structure at the cloud-top. Further, BOL will capture the fine temperature structure at polar region near the “eye” of the hemispheric vortex situated over the poles, where the horizontal temperature varies drastically near the Venus cloud-tops. VIRTIS instrument on Venus Express orbiter showed complex structures at near infrared wavelengths . Akatsuki from its near equatorial elliptical orbit cannot observe the fine structure in polar regions.
During 2012-2014, we developed an uncooled micro-bolometer array (UMBA) camera for the 50 kg class Earth observing satellite based on the experience of LIR development . The camera with the pixel size of 640 × 480 was launched in 2014 and successfully detect a small wildfire which was main observation target for the mission. The results showed that its performance was better than expected. Furthermore, the newest UMBA camera with the pixel size increased to 1024 × 768 has been developed for the next wildfire mission to take finer spatial resolution image with ~0.01 deg/pixel. Unfortunately, this camera has lost the launch opportunity. However, the flight-model has been assembled and has passed function tests. Since BOL does not need heavy cryogenic systems, its mass and size are less than ~1 kg and 100 mm x 100 mm x 120 mm, respectively; it would be a relatively small mass increment for the future Venus mission.
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 Fukuhara, T., et al., 2017, Detection of small wildfire by thermal infrared camera with the uncooled microbolometer array for 50 kg class satellite, IEEE Transactions on Geoscience and Remote Sensing, 2017, Vol. 55, No. 8, 4314-4324