山﨑 敦

©2016. American Geophysical Union. All Rights Reserved. While the Jovian magnetosphere is known to have the internal source for its activity, it is reported to be under the influence of the solar wind as well. Here we report the statistical relationship between the total power of the Jovian ultraviolet aurora and the solar wind properties found from long-term monitoring by the spectrometer EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) on board the Hisaki satellite. Superposed epoch analysis indicates that auroral total power increases when an enhanced solar wind dynamic pressure hits the magnetosphere. Furthermore, the auroral total power shows a positive correlation with the duration of a quiescent interval of the solar wind that is present before a rise in the dynamic pressure, more than with the amplitude of dynamic pressure increase. These statistical characteristics define the next step to unveil the physical mechanism of the solar wind control on the Jovian magnetospheric dynamics.

©2016. American Geophysical Union. All Rights Reserved. Temporal variation of Jupiter's northern aurora is detected using the Extreme Ultraviolet Spectroscope for Exospheric Dynamics (EXCEED) on board JAXA's Earth-orbiting planetary space telescope Hisaki. The wavelength coverage of EXCEED includes the H2 Lyman and Werner bands at 80–148 nm from the entire northern polar region. The prominent periodic modulation of the observed emission corresponds to the rotation of Jupiter's main auroral oval through the aperture, with additional superposed −50%–100% temporal variations. The hydrocarbon color ratio (CR) adopted for the wavelength range of EXCEED is defined as the ratio of the emission intensity in the long wavelength range of 138.5–144.8 nm to that in the short wavelength range of 126.3–130 nm. This CR varies with the planetary rotation phase. Short- (within one planetary rotation) and long-term (> one planetary rotation) enhancements of the auroral power are observed in both wavelength ranges and result in a small CR variation. The occurrence timing of the auroral power enhancement does not clearly depend on the central meridian longitude. Despite the limitations of the wavelength coverage and the large field of view of the observation, the auroral spectra and CR-brightness distribution measured using EXCEED are consistent with other observations.

©2015. American Geophysical Union. All Rights Reserved. Jupiter's auroral parameters are estimated from observations by a spectrometer EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) on board Japanese Aerospace Exploration Agency's Earth-orbiting planetary space telescope Hisaki. EXCEED provides continuous auroral spectra covering the wavelength range over 80–148 nm from the whole northern polar region. The auroral electron energy is estimated using a hydrocarbon color ratio adopted for the wavelength range of EXCEED, and the emission power in the long wavelength range 138.5–144.8 nm is used as an indicator of total emitted power before hydrocarbon absorption and auroral electron energy flux. The quasi-continuous observations by Hisaki provide the auroral electron parameters and their relation under different auroral activity levels. Short- (within < one planetary rotation) and long-term (> one planetary rotation) enhancements of auroral power accompany increases of the electron number flux rather than the electron energy variations. The relationships between the auroral electron energy (~70–400 keV) and flux (1026–1027/s, 0.08–0.9 μA/m2) estimated from the observations over a 40 day interval are in agreement with field-aligned acceleration theory when incorporating probable magnetospheric parameters. Applying the electron acceleration theory to each observation point, we explore the magnetospheric source plasma variation during these power-enhanced events. Possible scenarios to explain the derived variations are (i) an adiabatic variation of the magnetospheric plasma under a magnetospheric compression and/or plasma injection, and (ii) a change of the dominant auroral component from the main emission (main aurora) to the emission at the open-closed boundary.

AKATSUKI is the Japanese Venus Climate Orbiter that was designed to investigate the climate system of Venus. The orbiter was launched on May 21, 2010, and it reached Venus on December 7, 2010. Thrust was applied by the orbital maneuver engine in an attempt to put AKATSUKI into a westward equatorial orbit around Venus with a 30-h orbital period. However, this operation failed because of a malfunction in the propulsion system. After this failure, the spacecraft orbited the Sun for 5 years. On December 7, 2015, AKATSUKI once again approached Venus and the Venus orbit insertion was successful, whereby a westward equatorial orbit with apoapsis of similar to 440,000 km and orbital period of 14 days was initiated. Now that AKATSUKI's long journey to Venus has ended, it will provide scientific data on the Venusian climate system for two or more years. For the purpose of both decreasing the apoapsis altitude and avoiding a long eclipse during the orbit, a trim maneuver was performed at the first periapsis. The apoapsis altitude is now similar to 360,000 km with a periapsis altitude of 1000-8000 km, and the period is 10 days and 12 h. In this paper, we describe the details of the Venus orbit insertion-revenge 1 (VOI-R1) and the new orbit, the expected scientific information to be obtained at this orbit, and the Venus images captured by the onboard 1-mu m infrared camera, ultraviolet imager, and long-wave infrared camera 2 h after the successful initiation of the VOI-R1.

© 2016. American Geophysical Union. All Rights Reserved. Jupiter's X-ray auroral emission in the polar cap region results from particles which have undergone strong field-aligned acceleration into the ionosphere. The origin of precipitating ions and electrons and the time variability in the X-ray emission are essential to uncover the driving mechanism for the high-energy acceleration. The magnetospheric location of the source field line where the X-ray is generated is likely affected by the solar wind variability. However, these essential characteristics are still unknown because the long-term monitoring of the X-rays and contemporaneous solar wind variability has not been carried out. In April 2014, the first long-term multiwavelength monitoring of Jupiter's X-ray and EUV auroral emissions was made by the Chandra X-ray Observatory, XMM-Newton, and Hisaki satellite. We find that the X-ray count rates are positively correlated with the solar wind velocity and insignificantly with the dynamic pressure. Based on the magnetic field mapping model, a half of the X-ray auroral region was found to be open to the interplanetary space. The other half of the X-ray auroral source region is magnetically connected with the prenoon to postdusk sector in the outermost region of the magnetosphere, where the Kelvin-Helmholtz (KH) instability, magnetopause reconnection, and quasiperiodic particle injection potentially take place. We speculate that the high-energy auroral acceleration is associated with the KH instability and/or magnetopause reconnection. This association is expected to also occur in many other space plasma environments such as Saturn and other magnetized rotators.

Copyright © 2016 by the International Astronautical Federation (IAF). All rights reserved. Japan&#039;s Venus Climate Orbiter Akatsuki was proposed to ISAS (Institute of Space and Astronautical Science) in 2001 as an interplanetary mission. We made 5 cameras with narrow-band filters to image Venus at different wavelengths to track the cloud and minor components distribution at different heights to study the Venusian atmospheric dynamics in 3 dimension. It was launched on May 21st, 2010 and reached Venus on December 7th, 2010. With the thrust by the orbital maneuver engine, Akatsuki tried to go into the westward equatorial orbit around Venus with the 30 hours&#039; orbital period, however it failed by the malfunction of the propulsion system. Later the spacecraft has been orbiting the sun for 5 years. On December 7th, 2015 Akatsuki met Venus again after the orbit control and Akatsuki was put into the westward equatorial orbit whose apoapsis is about 0.44 million km and orbital period of 14 days. Its main target is to shed light on the mechanism of the fast atmospheric circulation of Venus. The systematic imaging sequence by Akatsuki is advantageous for detecting meteorological phenomena with various temporal and spatial scales. We have five photometric sensors as mission instruments for imaging, which are 1 m-infrared camera (IR1), 2 m-infrared camera (IR2), ultra-violet imager (UVI), long-wave infrared camera (LIR), and lightning and airglow camera (LAC). These photometers except LIR have changeable filters in the optics to image in certain wavelengths. Akatsuki&#039;s long elliptical orbit around Venus is suitable for obtaining cloud-tracked wind vectors over a wide area continuously from high altitudes. With the observation, the characterizations of the meridional circulation, mid-latitude jets, and various wave activities are anticipated. The technical issues of Venus orbit insertion in 2015 and the scientific new results will be given in this paper.

©2015. American Geophysical Union. All Rights Reserved. Io-correlated brightness change in the Io plasma torus (IPT) was discovered by the Voyager spacecraft, showing evidence of local electron heating around Io. However, its detailed properties and the cause of electron heating are still open issues. The extreme ultraviolet spectrograph on board the HISAKI satellite continuously observed the IPT from the end of December 2013 to the middle of January 2014. The variation in the IPT brightness showed that clear periodicity associated with Io's orbital period (42 h) and that the bright region was located downstream of Io. The amplitude of the periodic variation was larger at short wavelengths than at long wavelengths. From spectral analyses, we found that Io-correlated brightening is caused by the increase in the hot electron population in the region downstream of Io. We also found that the brightness depends on the system III longitude and found primary and secondary peaks in the longitude ranges of 100-130° and 250-340°, respectively. Io's orbit crosses the center of the IPT around these longitudes. This longitude dependence suggests that the electron heating process is related to the plasma density around Io. The total radiated power from the IPT in January 2014 was estimated to be 1.4 TW in the wavelength range from 60 to 145 nm. The Io-correlated component produced 10% of this total radiated power. The interaction between Io and the IPT continuously produces a large amount of energy around Io, and 140 GW of that energy is immediately converted to hot electron production in the IPT.

© 2014 Elsevier Inc. We present phase curves for Venus in the 1-2μm wavelength region, acquired with IR1 and IR2 on board Akatsuki (February-March 2011). A substantial discrepancy with the previously-published curves was found in the small phase angle range (0-30°). Through analysis by radiative-transfer computation, it was found that the visibility of larger (~1μm or larger) cloud particles was significantly higher than in the standard cloud model. Although the cause is unknown, this may be related to the recently reported increase in the abundance of SO2 in the upper atmosphere. It was also found that the cloud top is located at ~75km and that 1-μm particles exist above the cloud, both of these results being consistent with recent studies based on the Venus Express observations in 2006-2008. Further monitoring, including photometry for phase curves, polarimetry for aerosol properties, spectroscopy for SO2 abundance, and cloud opacity measurements in the near-infrared windows, is required in order to understand the mechanism of this large-scale change.

We developed a method to calibrate optical distortion parameters for axisymmetrical optical systems using images of a spherical target taken at a variety of distances. The method utilizes the fact that the influence of distortion on the apparent radius in the image changes with the disk size of the projected body. Because several planets can be used as the spherical target, this method enables us to obtain distortion parameters in space and by using a large number of planetary images, desired accuracy of parameters can be achieved statistically. The applicability of the method was tested by applying it to simulated planetary images and real Venus images taken by Venus Monitoring Camera onboard the ESA's Venus Express, and optical distortion was successfully retrieved with the pixel position error of less than 1 pixel. Venus is the planet most suitable for the proposed method because of its smooth, nearly spherical surface of the haze layer covering the planet. (C) 2013 Elsevier Ltd. All rights reserved.

The Telescope of Extreme Ultraviolet (TEX) onboard Japan's lunar orbiter KAGUYA provided the first sequential images of the Earth's plasmasphere from the "side" (meridian) view. The TEX instrument obtained the global distribution of the terrestrial helium ions (He+) by detecting resonantly scattered emission at 30.4 nm. One of the most striking features of the plasmasphere found by TEX is an arc-shaped structure of enhanced brightness, which we call a "plasmaspheric filament". In the TEX image on 2 June 2008, the filament structure was clearly aligned to the dipole magnetic field line of L = 3.7 at 7.3 magnetic local time. Our analysis suggests that the filament represents an isolated flux tube filled with four times higher He + density than its neighbors. We found four events of plasmaspheric filament in the images obtained between March and June 2008, and in all four events, the geomagnetic activity was quite low. The plasmaspheric filament in the TEX image is the first evidence that a "finger" structure seen in the IMAGE-EUV image is the projection of an isolated flux tube. © 2013. American Geophysical Union. All Rights Reserved.

The Extreme Ultraviolet Imagers (EUVIs) were launched on 21st July 2012 as payloads to the Exposed Facility of the Japanese Experiment Module (JEM-EF) on the International Space Station. The EUVIs are parts of the IMAP (Ionosphere, Mesosphere, upper Atmosphere, and Plasmasphere mapping) mission to observe the Earth's upper atmosphere, mesosphere, ionosphere, thermosphere and plasmasphere. The other part of IMAP is a visible and near-infrared spectral imager (VISI). In this mission, we install two independent and identical telescopes. One telescope detects the terrestrial EUV emission from O+ (at the wavelength of 83.4 nm), and the other one detects He+ (30.4 nm). At the altitude of approximately 400 km, the two telescopes direct towards the Earth's limb to look at the ionosphere and plasmasphere from the inside-out. The maximum spatial resolution is 0.1 degrees and time resolution is 1 minute. The optical instruments consist of multilayer coated mirrors which are optimized for 30.4 nm, metallic thin filters and 5-stage microchannel plates to pick up photon events efficiently. In our presentation, we report the mission overview, the instruments and the result of ground calibrations.

The extreme ultraviolet (EUV) telescope EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) onboard the Japan's small satellite SPRINT-A will be launched in August 2013. The EXCEED instrument will observe tenuous gases and plasmas around the planets in the solar system (e.g., Mercury, Venus, Mars, Jupiter, and Saturn). The EXCEED instrument is designed to have a spectral range of 60-145 nm with a spectral resolution of 0.4-1.0 nm. The instrument has a field of view of 400 '' x 140 '' (maximum), and the attitude fluctuations are stabilized within +/- 5 ''. The optics of the instrument consists of an entrance mirror with a diameter of 200 mm, three types of slits, two types of filters, a laminar type grating, and a 5-stage microchannel plate assembly with a resistive anode encoder. In this paper, we report the general mission overview, the instrumentations, and the results of ground calibrations.

Japanese Venus Climate Orbiter/AKATSUKI was proposed in 2001 with strong support by international Venus science community and approved as an ISAS (Institute of Space and Astronautical Science) mission soon after the proposal. The mission life we expected was more than two Earth years in Venus orbit. AKATSUKI was successfully launched at 06:58:22JST on May 21, 2010, by H-IIA F17. After the separation from H-IIA, the telemetry from AKATSUKI was normally detected by DSN Goldstone station (10:00JST) and the solar cell paddles' expansion was confirmed. The malfunction happened on the propulsion system during the Venus orbit insertion (VOI) on Dec 7, 2010. We failed to make the spacecraft become a Venus orbiter, and the spacecraft entered an orbit around the Sun with a period of 203 days. Most of the fuel still had remained, but the orbital maneuvering engine was found to be broken. We decided to use only the reaction control system (RCS) for orbital maneuver and three minor maneuvers in Nov 2011 were successfully done so that AKATSUKI will meet Venus in 2015. We are considering several scenarios for VOI using only RCS. Copyright © (2012) by the International Astronautical Federation.

An earth–orbiting extreme ultraviolet (EUV) spectroscopic mission, EXtreme ultraviolet speCtroscope for ExosphEric Dynamics explore (EXCEED) that will be launched in2012 is now under development. The EXCEED mission will carry out out–of–atmosphere observations of EUV (60–145 nm) emissions from tenuous plasmas around the planets (Mercury, Mars, Venus, and Jupiter). In this paper, we will introducethe general mission overview, the instrument, and the scientific targets.

EXtreme ultraviolet spectrosCope for ExosphEric Dynamics (EXCEED) will carry out the extreme ultraviolet (EUV) spectroscopic imaging observations from earth orbit. It clarifies the plasma distributions and compositions around the various planets and examines the interactions with the solar wind. Observations should be carried out at high altitude so that the earth's atmospheric absorption is free. Our spectral range is from 60 to 145 nm and the spectral resolution is 0.3 to 1 nm (FWHM). The mission is planned to be launched in 2013, beginning of the next period of solar maximum. In this paper, we will introduce the general mission overview, scientific objectives and development of instrument.

At the end of previous century, we succeeded to image the Earth's plasmasphere from the space by EUV spectral range. Then, spacecraft missions were carried out to image the terrestrial EUV emissions. The extreme ultraviolet imagers (EUVIs) on the international space station (ISS) will be launched in 2012. At the altitude of approximately 400 km, two telescopes direct toward the Earth's limb to look the ionosphere and plasmasphere from the inside-out. One telescope detects the terrestrial EUV emission at O + (83.4 nm), and the other is He + (30.4 nm). These two EUV emissions are solar-scattered by ionized oxygen and helium, respectively. The maximum spatial and time resolutions are 0.1 degree and 1 minute, respectively. Our observation methods will become standard to probe the Earth's upper atmosphere. © 2011 The Institute of Electrical Engineers of Japan.

The Akatsuki spacecraft of Japan was launched on May 21, 2010. The spacecraft planned to enter a Venus-encircling near-equatorial orbit in December 7, 2010; however, the Venus orbit insertion maneuver has failed, and at present the spacecraft is orbiting the Sun. There is a possibility of conducting an orbit insertion maneuver again several years later. The main goal of the mission is to understand the Venusian atmospheric dynamics and cloud physics, with the explorations of the ground surface and the interplanetary dust also being the themes. The angular motion of the spacecraft is roughly synchronized with the zonal flow near the cloud base for roughly 20 hours centered at the apoapsis. Seen from this portion of the orbit, cloud features below the spacecraft continue to be observed over 20 hours, and thus the precise determination of atmospheric motions is possible. The onboard science instruments sense multiple height levels of the atmosphere to model the three-dimensional structure and dynamics. The lower clouds, the lower atmosphere and the surface are imaged by utilizing near-infrared windows. The cloud top structure is mapped by using scattered ultraviolet radiation and thermal infrared radiation. Lightning discharge is searched for by high speed sampling of lightning flashes. Night airglow is observed at visible wavelengths. Radio occultation complements the imaging observations principally by determining the vertical temperature structure.

© 2011 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. The EXCEED mission is an Earth-orbiting extreme ultraviolet (EUV) spectroscopic mission and the first in the SPRINT series being developed by ISAS/JAXA. EUV spectroscopy is suitable for observing tenuous gases and plasmas around planets in the solar system (e.g., Mercury, Venus, Mars, Jupiter, and Saturn). One of the primary observation targets is Jupiter, whose magnetospheric plasma dynamics is dominated by planetary rotation. In the EUV range, a number of emission lines originate from plasmas distributed in Jupiter's inner magnetosphere. The EXCEED spectrograph is designed to have a wavelength range of 55–145 nm with minimum spectral resolution of 0.4 nm, enabling the electrontemperature and ion composition in the inner magnetosphere to be determined. Thespectrograph slits have a field of view of 400 × 140 arc-seconds (maximum), and an onboard target guide camera is used to stabilize attitude fluctuations to within ±5 arc-seconds. With a large primary mirror (diameter: 20 cm) and high detection efficiencies (1–3%), EXCEED will measure Io plasma torus emission distributions with a good signal-to-noise ratio using an exposure time of 50 minutes and achieving spatial resolution of 20arc-seconds. The previous observation of plasmas in the inner magnetosphere and the aurora with an EUV spectrograph was done by the Cassini spacecraft over a period of a few months. We re-examined the data obtained by the UVIS instrument to clarify the scientific objectives for the EXCEED mission. The UVIS observation sometimes showed sudden brightening in both the aurora and the Io plasma torus with a timescale from several hours to a few tens of hours. From the reanalysis of the UVIS dataas well as radio waves (Cassini/RPWS) and the interplanetary magnetic field (Galileo/MAG) data, we found that thebrightening events were related to a large-scale structure inthe solar wind. However, because the Cassini observations had a lack of continuity due to the intermittent observation mode, it is difficult to make a definitive relation between the aurora and the plasma emissions in the inner magnetosphere. EXCEED plans to observe the variations in the aurora and in the radial structures of plasma emissions andshould reveal the relationship between them in detail. The EXCEED observations are expected to investigate the radial plasma and energy transport processes in the rotation-driven magnetosphere.

Planet-C, "AKATSUKI", is the first Venus exploration program of ISAS/JAXA. AKATSUKI was successfully launched in May 21, 2010 from Tanegashima Space Center (TSC) in Japan by using Japanese H-IIA rocket. And it acquired the first light, the image of earth, 13 hours after the launch. This paper introduces, science objectives, spacecraft and instruments, launch and first light acquisition of AKATSUKI.

An Earth-orbiting small satellite "EXtreme ultraviolet spectrosCope for ExosphEric Dynamics" (EXCEED) which will be launched in 2012 is under development. The mission will carry out spectroscopic and imaging observation of EUV (Extreme Ultraviolet: 60145 nm) emissions from tenuous plasmas around the planets (Venus, Mars, Mercury, and Jupiter). It is essential for EUV observation to put on an observing site outside the Earth's atmosphere to avoid the absorption. It is also essential that the detection efficiency must be very high in order to catch the faint signals from those targets. In this mission, we employ cesium iodide coated microchannel plate as a 2 dimensional photon counting devise which shows 1.5-50 times higher quantum detection efficiency comparing with the bared one. We coat the surface of the grating and entrance mirror with silicon carbides by the chemical vapor deposition method in order to archive the high diffraction efficiency and reflectivity. The whole spectrometer is shielded by the 2 mm thick stainless steel to prevent the contamination caused by the high energy electrons from the inner radiation belt. In this paper, we will introduce the mission overview, its instrument, and their performance. (C) 2009 COSPAR. Published by Elsevier Ltd. All rights reserved.

Our understanding of plasmaspheric dynamics has increased in recent years largely due to the information generated during the IMAGE-EUV mission. Even though this successful mission has ended, we have succeeded in imaging the terrestrial helium ions (He(+)) by the Telescope of Extreme Ultraviolet (TEX) aboard the Japanese lunar orbiter KAGUYA by detecting resonantly scattered emission at 30.4 nm. The view afforded by the KAGUYA orbit encompasses the plasma (He(+)) distribution in a single exposure, enabling us to examine for the first time the globally averaged properties of the plasmasphere from the "side" (meridian) perspective. The TEX instrument observed a medium-scale density structure in the dawnside plasmasphere during a quiet period (1-2 June 2008). The meridian shape of the structure clearly agreed with the dipole magnetic field line. The TEX instrument also observed the structure in the plasmasphere co-rotating with a duration of 26 h, which is consistent with results from a number of recent studies derived from the IMAGE-EUV mission. These results confirm that the TEX instrument successfully obtained the spatial distribution and temporal variation of the plasmasphere.

We have succeeded in observations by the Telescope of Extreme Ultraviolet (TEX) aboard Japan's lunar orbiter KAGUYA to characterize the evolution of the Earth's plasmasphere. The view afforded by the KAGUYA orbit encompasses the plasma distribution in a single exposure, enabling us to examine for the first time the globally-averaged properties of the plasmasphere from the side (meridian) view. We focus on a study period that began with a likely moderate erosion event of plasma patches in a geomagnetically disturbed period, and follow refilling of plasma from the upper ionosphere. The Earth's plasmasphere grew up to saturated level at the rate of approximately 1,600 km per day to 4,800 km per day on the equatorial plane. From the “side view” of the Earth, a specific magnetic flux tube with cold dense plasmas was seen and likely moved to outer magnetosphere, even while geomagnetic activity was low. From the moon, we are studying the terrestrial plasmas in the vicinity of the Earth. This is called “Geoscience from the Moon”.

EXtreme ultraviolet spectrosCope for ExosphEric Dynamics (EXCEED) is the earth-orbiting Extreme Ultraviolet (EUV) spectroscope mission which dedicates to the planetary space science. Our mission will carry out the EUV spectroscopic imaging which clarifies the plasma distributions and compositions around the planets and examines the interaction with the solar wind. Orbital altitude should be enough high so that the earth's atmospheric absorption is free. The spectral range of the mission is from 60 to 145 nm and the resolution is 0.2 to 0.5 nm FWHM. The mission is planned to be launched in 2013, beginning of the next period of solar maximum. In this paper, we will introduce the general mission overview, its instrument and its scientific targets.

EXtreme ultraviolet spectrosCope for ExosphEric Dynamics (EXCEED) will carry out the extreme ultraviolet (EUV) spectroscopic imaging observations from earth orbit. It clarifies the plasma distributions and compositions around the various planets and examines the interactions with the solar wind. Observations should be carried out at high altitude so that the earth's atmospheric absorption is free. Our spectral range is from 60 to 145 nm and the spectral resolution is 0.2 to 0.5 nm (FWHM). The mission is planned to be launched in 2013, beginning of the next period of solar maximum. In this paper, we will introduce the general mission overview, scientific objectives and development of instrument.

EXtreme ultraviolet spectrosCope for ExosphEric Dynamics (EXCEED) is an earth-orbiting space Extreme Ultraviolet (EUV) telescope mission. The satellite will be launched in 2012 by a Japanese new solid propulsion rocket and injected into the elliptic orbit around the earth. The orbital altitude is 900 to 1200 km for perigee and apogee respectively. EXCEED will make EUV spectroscopic and imaging observations of plasma space around various planets in our solar system. The wavelength range is from 60 to 145 nm and the resolution is 0.2 to 0.5 nm FWHM. It enables us to study Io plasma torus of Jupiter, and interaction of the solar wind with the upper atmosphere of the terrestrial planets and their escape. In this paper, we will introduce the mission overview and its instrument especially for holographic grating which is coated by Chemical vapor deposited silicon carbide. © 2009 Copyright SPIE - The International Society for Optical Engineering.

The Upper Atmosphere and Plasma Imager (UPI) is to be launched in 2007 and sent to the Moon. From the lunar orbit, two telescopes are to be directed towards the Earth. The Moon has no atmosphere, which results in there being no active emission near the spacecraft; consequently, we will have a high-quality image of the near-Earth environment. As the Moon orbits the Earth once a month, the Earth will also be observed from many different directions. This is called a "science from the Moon". The two telescopes are mounted on a two-axis gimbal system, the Telescope of Extreme ultraviolet (TEX) and Telescope of Visible light (TVIS). TEX detects the O II (83.4 nm) and He II (30.4 nm) emissions scattered by ionized oxygen and helium, respectively. The targets of extreme-ultraviolet (EUV) imaging are the polar ionosphere, the polar wind, and the plasmasphere and inner magnetosphere. The maximum spatial and time resolutions are 0.09 Re and 1 min, respectively.

The Upper Atmosphere and Plasma Imager (UPI) is to be launched in 2007 and sent to the Moon. From the lunar orbit, two telescopes are to be directed towards the Earth. The Moon has no atmosphere, which results in there being no active emission near the spacecraft; consequently, we will have a high-quality image of the near-Earth environment. As the Moon orbits the Earth once a month, the Earth will also be observed from many different directions. This is called a "science from the Moon". The two telescopes are mounted on a two-axis gimbal system, the Telescope of Extreme ultraviolet (TEX) and Telescope of Visible light (TVIS). TEX detects the O II (83.4 nm) and He II (30.4 nm) emissions scattered by ionized oxygen and helium, respectively. The targets of extreme-ultraviolet (EUV) imaging are the polar ionosphere, the polar wind, and the plasmasphere and inner magnetosphere. The maximum spatial and time resolutions are 0.09 Re and 1 min, respectively. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB.

EXtreme ultraviolet spectrosCope for ExosphEric Dynamics (EXCEED) is an earth-orbiting space Extreme Ultraviolet (EUV) telescope mission that will be launched in 2012 and injected into the orbit around the earth. EXCEED will make observations of plasma space in various planets in our solar system. It is very important to put on an observing site beyond the atmospheric absorption when we observe EUV spectral range, and which enables us to study Io plasma torus of Jupiter, and interaction of the solar wind with the upper atmosphere of the planets and their escape. In this paper, we will introduce the mission overview, its instrument, and the scientific targets.

The Longwave Infrared Camera (LIR), which mounts an uncooled micro-bolometer array (UMBA), is under development for the Japanese Venus orbiter mission, PLANET-C. LIR detects thermal emission from the top of the sulfur dioxide cloud in a wavelength region 8-12 mu m to map the cloud-top temperature which is typically as low as 230 K. The requirement for the noise equivalent temperature difference (NETD) is 0.3 K. Images of blackbody targets in room temperature (similar to 300 K) and low temperature (similar to 230 K) have been acquired in a vacuum environment using a prototype model of LIR, showing that the NETD of 0.2 K and 0.8 K are achieved in similar to 300 K and -230 K, respectively. We expect that the requirement of NETD &lt; 0.3 K for similar to 230 K targets will be achieved by averaging several tens of images which are acquired within a few minutes. The vibration test for the UMBA was also carried out and the result showed the UMBA survived without any pixel defects or malfunctions. The tolerance to high-energy protons was tested and verified using a commercial camera in which a same type of UMBA is mounted. Based on these results, a flight model is now being manufactured with minor modifications from the prototype.

The purpose of this paper is to clarify how the average structure of the Venus nightside ionopause for solar zenith angles (SZA) greater than 90° depends on (1) the direction and (2) the magnitude of the motional electric field of the solar wind. Plasma density structure in the Venus nightside ionosphere has been investigated by using data sets of the Pioneer Venus Orbiter observations. It is found that the distribution of the nightside ionopause locations is asymmetric with respect to the direction of the solar wind electric field, leaning opposite to the electric field vector. It is also found that the asymmetry is increasingly prominent as the magnitude of the motional electric field increases, while not so prominent for small field magnitude. This result suggests that the asymmetric ionopause location in the nightside is related to the acceleration of pickup ions. Copyright 2006 by the American Geophysical Union.

According to previous theories a large number of oxygen ions are not able to escape from the ionosphere to the magnetosphere due to its heavy mass and loss process in the upper atmosphere. Recent satellite observations, however, reveal that oxygen ions of the ionospheric origin exist in the magnetosphere, and that the outflow flux from the polar ionosphere is comparable to that of hydrogen ions, which have its light mass, during the high solar activity and the high geomagnetic activity. The distribution of oxygen ions provides the interpretation of the plasma transfer during the high activity, and gives us the effective information for monitoring the space weather. The remote-sensing method is useful for the measurement of the distribution of oxygen ions all over the magnetosphere. We advance development of new optics for the resonance scattering emission of oxygen ions.