A5090336344- Planetary Science and Exploration
- Astro and Planetary Science
- Space Exploration and Technology
- Space Science and Extraterrestrial Life
- Solar and Space Plasma Dynamics
- Space exploration and regulation
- Spaceflight effects on biology
- Stellar, planetary, and galactic studies
- Geomagnetism and Paleomagnetism Studies
- Geology and Paleoclimatology Research
- Atmospheric Ozone and Climate
- Atmospheric and Environmental Gas Dynamics
- Spacecraft Design and Technology
- Ionosphere and magnetosphere dynamics
- Calibration and Measurement Techniques
- History and Developments in Astronomy
- Astronomical Observations and Instrumentation
- Spacecraft and Cryogenic Technologies
- Atmospheric aerosols and clouds
- Astrophysics and Star Formation Studies
- Spectroscopy and Laser Applications
- Lightning and Electromagnetic Phenomena
- Spacecraft Dynamics and Control
- Scientific Research and Discoveries
- Aeolian processes and effects
Japan Aerospace Exploration Agency
2015-2024
Institute of Space and Astronautical Science
2015-2024
The University of Tokyo
1991-2024
Tohoku University
2024
The Graduate University for Advanced Studies, SOKENDAI
2012-2024
International Society of Automation
2017-2021
National Sagamihara Hospital
2018-2021
Hokkaido Information University
2020
Hokkaido University
2020
Kumamoto University
2007
Spherical harmonic models of the planetary magnetic field Jupiter are obtained from in situ measurements and remote observations position foot Io flux tube Jupiter's ionosphere. The (IFT) footprint locates ionospheric lines traced Io's orbital radial distance equator plane (5.9 Jovian radii). IFT is a valuable constraint on models, providing “ground truth” information region close to planet thus far not sampled by spacecraft. represented using spherical expansion degree order 4 for...
The electrodynamic interaction between lo and the Jovian magnetosphere drives currents to from planet's ionosphere, where H(3)(+) emission is excited. Direct images of this phenomenon were obtained with ProtoCAM infrared camera at National Aeronautics Space Administration's 3-m Infrared Telescope Facility. emissions are localized instantaneous foot flux tube, approximately 8 degrees equatorward more intense auroral associated higher magnetic latitudes. tube leads that (undisturbed) model...
AKATSUKI is the Japanese Venus Climate Orbiter that was designed to investigate climate system of Venus. The orbiter launched on May 21, 2010, and it reached December 7, 2010. Thrust applied by orbital maneuver engine in an attempt put into a westward equatorial orbit around with 30-h period. However, this operation failed because malfunction propulsion system. After failure, spacecraft orbited Sun for 5 years. On 2015, once again approached insertion successful, whereby apoapsis ~440,000 km...
After the arrival of Akatsuki spacecraft Japan Aerospace Exploration Agency at Venus in December 2015, radio occultation experiment, termed RS (Radio Science), obtained 19 vertical profiles Venusian atmosphere by April 2017. An onboard ultra-stable oscillator is used to generate stable X-band downlink signals needed for experiment. The quantities be retrieved are atmospheric pressure, temperature, sulfuric acid vapor mixing ratio, and electron density. Temperature were successfully down ~ 38...
We present observational evidence of the variation cloud‐tracked zonal velocity by ~20 m s –1 with a timescale few hundred days in southern low latitude region based on an analysis cloud images taken Venus Monitoring Camera board Express. A spectral suggests that has periodicity period about 255 days. Although features are not always passive tracers, periodical dynamical state is robust feature. Superposed this long‐term velocity, Kelvin wave‐like disturbances tend to be observed periods...
Explaining super-rotation on Venus The solid surface of rotates very slowly, once every 243 days, but its thick atmosphere circles the planet in just 4 days. This phenomenon, known as super-rotation, requires a continuous input angular momentum, from an unknown source, to overcome friction with surface. Horinouchi et al. mapped planet's winds using ultraviolet observations Venus' clouds orbiting Akatsuki spacecraft (see Perspective by Lebonnois). They incorporated these data into global...
The Akatsuki spacecraft of Japan was launched on May 21, 2010. planned to enter a Venus-encircling near-equatorial orbit in December 7, 2010; however, the Venus insertion maneuver has failed, and at present is orbiting Sun. There possibility conducting an again several years later. main goal mission understand Venusian atmospheric dynamics cloud physics, with explorations ground surface interplanetary dust also being themes. angular motion roughly synchronized zonal flow near base for 20...
Abstract The existence of large stationary gravity waves was discovered during Akatsuki's first observation sequence in 2015. In this study, the further detection brightness temperature images over a 1.5 year period is reported. periodically appeared mostly above four specific highland regions low latitudes when these were local afternoon. wave amplitudes attenuated after locations passed beyond evening terminator, and tended to slowly drift eastward their lifetimes. appearances depend not...
The ultraviolet imager (UVI) has been developed for the Akatsuki spacecraft (Venus Climate Orbiter mission). UVI takes (UV) images of solar radiation reflected by Venusian clouds with narrow bandpass filters centered at 283 and 365 nm wavelengths. There are absorption bands SO2 unknown absorbers in these wavelength regions. UV provide spatial distribution absorber around cloud top altitudes. also allow us to understand morphologies haze properties. Nominal sequential 2-h intervals used...
Cloud patterns are important clues for revealing the atmospheric circulation of Venus. Recently, a planetary-scale streak structure has been discovered in middle- and lower-cloud images Venus' night-side taken by IR2, 2-μm camera, on board Akatsuki orbiter. However, its formation mechanism not investigated. Here we succeed, first time, reproducing observed structure, as regions strong downward flows that develop high-resolution global simulations Venus atmosphere. The streaks formed both...
Observations of the jovian system in near-infrared (3.4 μm) reveal a wealth information about Jupiter's magnetic field, magnetosphere, and magnetospheric dynamics. This wavelength contains few emission lines H3+ ion it is centred on deep methane absorption band. As result, one can image ionosphere at this with extraordinary signal–to–noise ratio, against planet otherwise darkened by due to its atmosphere. High spatial resolution images planet's surface provide synoptic view entire from...
Since insertion into orbit on December 7, 2015, the Akatsuki orbiter has returned global images of Venus from its four imaging cameras at eleven discrete wavelengths ultraviolet (283 and 365 nm) near infrared (0.9–2.3 µm), to thermal (8–12 µm) a near-equatorial orbit. The Express Pioneer Orbiter missions have also monitored planet for long periods but polar or near-polar orbits. wavelength coverage views differ all three missions. In reflected light, reveal features seen cloud tops (~ 70 km...
Abstract Since December 2015, Ultraviolet Imager (UVI) onboard Akatsuki has been observing Venus clouds at the wavelengths of 283 and 365 nm. Horizontal winds near cloud top derived from UVI images over ∼7 earth years are analyzed to elucidate spatial temporal variability superrotation planetary‐scale waves. Zonal averaged analysis period asymmetric with respect equator, being faster in southern hemisphere. This asymmetry varied temporarily was occasionally reverted. Comparison two suggests...
The first year (December 2015 to November 2016) of IR2 after Akatsuki's successful insertion an elongated elliptical orbit around Venus is reported with performance evaluation and results data acquisition. single-stage Stirling-cycle cryo-cooler has been operated various driving voltages achieve the best possible cooling under given thermal environment. A total 3091 images (1420 dayside at 2.02 μm 1671 night-side 1.735, 2.26, 2.32 μm) were acquired in this period. Additionally, 159 images,...
Longwave Infrared Camera (LIR) onboard Akatsuki first revealed the global structure of thermal tides in upper cloud layer Venus. The data were acquired over three Venusian years, and analysis was done areas from equator to mid-latitudes both hemispheres whole local time. Thermal at two vertical levels analyzed by comparing different emission angles. Dynamical wave modes consisting identified; diurnal tide consisted mainly Rossby-wave gravity-wave modes, while semidiurnal predominantly a...
The Venus Climate Orbiter Akatsuki arrived at in December 2015, and the Longwave Infrared Camera (LIR) onboard spacecraft started making observations. LIR has acquired more than 8000 images during first two Venusian years since orbit insertion without any serious faults. However, brightness temperature derived from contained an unexpected bias that related not to natural phenomena but a thermal condition of instrument. could be partially eliminated by keeping power supply unit for always...