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In order to determine the effect of impact angle on the impact strength of icy planetesimals, we conducted a range of oblique impact experiments for spherical ice and snow targets simulating icy planetesimals at different thermal evolution stages. The ice targets had no porosity and the snow targets had a porosity of 0.5. A polycarbonate or glass sphere impacted the ice targets at 744–1747 m s−1 and the snow targets at 938–5085 m s−1 over a range of impact angles from grazing to head-on collisions. All experiments were conducted using a two-stage light gas gun and a target chamber set in a cold room of −15 °C at Kobe University, Japan. The impact strength, which is a specific energy, Q , when the largest fragment mass is a half of the original target mass, for the ice and snow targets in a head-on collision was determined to be 12 and 520 J kg−1, respectively, whereas it was found that the impact strength depended on the impact velocity. Thus, the normalized largest fragment mass, m l / M t , could well scale with the velocity dependent Q , that is, Q v i γ (where m l and M t are the masses of largest fragment and target, respectively, and v i is the impact velocity). At high Q , m l / M t increased drastically with the decrease of impact angle when the impact angle was smaller than a critical angle, θ c , and θ c ~ 30° for the ice targets and θ c ~ 45° for the snow targets. At small Q , m l / M t continued to increase as the impact angle became smaller for both types of targets. The m l / M t for oblique impacts had a good correlation with the effective specific energy, Q eff = Q sin 2 θ , where θ is the impact angle, and the effective impact strength was determined to be 16 J kg−1 and 499 J kg−1 for the ice and snow targets, irrespective of the impact angle. Furthermore, the scaling parameter, Π s _ eff , which was proposed by Housen and Holsapple (1990) but includes Q eff instead of Q , multiplied by 1 − ϕ λ , where ϕ is the porosity, showed even better correlation with m l / M t , and all m l / M t data of ice and snow targets could be merged, irrespective of impact velocity and ϕ. Based on our experimental results and a theory on the oblique impact of solar system bodies proposed by Shoemaker (1962) , we could estimate the degree of disruption (m l / M t) at any impact energy and any impact angle for icy planetesimals. Our findings demonstrate that the degree of disruption for icy planetesimals that have experienced sufficient thermal evolution was larger than that for those that did not experience significant thermal evolution. • We conducted impact experiments for ice and snow spheres at various impact angles. • We found that impact strength for head-on collisions depended on impact velocity. • Effective specific energy was useful in describing the effect of the impact angle. • We estimated the degree of disruption at various impact energies and impact angles. [ABSTRACT FROM AUTHOR]

Wind solar towers constitute a fairly new scheme for harvesting renewable energy from solar and wind energy sources. In such a tower, solar radiation is collected and hot air is enforced to go fast through the tower, a process called thermal updraft, which fuels a wind turbine to generate power. Using vortex generators at the top of the tower creates a pressure difference, which increases the thermal updraft. In this work, we describe the setup of a wind solar tower system established at Kyushu University in Japan. Then, we demonstrate how data was collected from this system in order to train regression models for thermal updraft prediction. The feature selection process was guided by sensitivity analysis. After that, several machine learning models were investigated and the most suitable model was selected based on quality and time metrics. The linear regression model was particularly examined in detail, and was shown to have a satisfactory high accuracy of thermal updraft prediction graphically and numerically with a coefficient of determination of R 2 = 0.981. We also evaluated a reduced prediction model based on the six most essential features, which could be a reduced model description for the WST. This reduced model showed little performance degradation (R 2 = 0.974), with significant reduction in the needed effort and resources, as well as data collection requirements. [Display omitted] • Wind solar tower: renewable energy technique that combines powers from solar & wind. • Machine learning methods gained research momentum because of their prediction capabilities. • The linear regression model was accurately sufficient in predicting thermal updraft. [ABSTRACT FROM AUTHOR]

Context. The JAXA asteroid sample return mission Hayabusa2 acquired a huge quantity of data from the asteroid (162173) Ryugu during its 1.5 years in asteroid proximity orbit. On December 5, 2020 (Japan time), Hayabusa brought back to Earth a 5.4 g sample from Ryugu's surface. Aims. We analyzed the near-infrared spectra of Ryugu, in particular the band at 2.72 μm, with the aim to investigate the hydrogen content of the H2O and OH− groups in hydrated phyllosilicates on Ryugu's surface. Aims. We applied two different methods, normalized optical path length (NOPL) and effective single-particle absorption thickness (ESPAT), to the 3 μm region absorption band, and we compared the obtained spectral parameters with those obtained from carbonaceous chondrite meteorites whose H content was determined in the laboratory. Methods. We derived an exponential correlation between the selected meteorite H content and its respective ESPAT and NOPL parameters. The average value of the H content obtained on Ryugu's surface with its relative variations, combining the results obtained with the two methods, is 0.52−0.21+0.16 0. 52 − 0.21 + 0.16 $ 0.52 _{-0.21}^{+0.16} $ wt.%. These methods can be applied to other asteroids that exhibit a 3 μm region absorption band to estimate the mean average of H content. Results. The results of the ESPAT and NOPL methods used on the Ryugu spectral data present small variations across Ryugu's surface and do not show any evident relation with the surface geomorphological structures. Our estimation of the global average H content of Ryugu is in agreement with those of several aqueously altered carbonaceous chondrites measured in the laboratory and is most similar to the H content of heated CM. The study of phyllosilicate H2O and OH− group hydrogen content on Ryugu and the derived method may be applied to other observed primitive asteroids. The obtained results will allow Solar System evolution models to be constrained and will allow the formation and evolution of the Solar System to be better understood. [ABSTRACT FROM AUTHOR]

Automotive head‐up displays (HUDs) use windshields as part of the display system and are used as partial reflectors for reflecting the images formed inside the dash board towards the driver. The locations of the aerial images are usually at the bumper of the vehicle and beyond, depending on the requirements. One of the major issues with such HUD system is the solar loading created by sunlight shining into the system through the image forming optics with focusing properties especially when the sun is shining into the HUD system in an off‐axis manner. This paper describes a HUD system where the imaging system uses a Micro‐Mirror Array Plate (MMAP) with an optical design that eliminates the issues associated with the off‐axis sunlight. Solar loading is an important design criterion as the HUD optics concentrate the sunlight to levels that can damage the display panel. Based on the aerial imaging properties of MMAP, this design would be applicable to the use of Dihedral Corner Reflector Array (DCRA), and Aerial Imaging by Retro‐Reflection (AIRR). Bench‐top system has been set up using MMAP from ASKA3D, Japan with the expected imaging properties. A complete prototype is being fabricated and will be reported. [ABSTRACT FROM AUTHOR]

NASA scientists have obtained samples from the asteroid Bennu, which they described as a pristine remnant of the early Solar System. The samples contain a diverse array of carbon-bearing molecules, providing insight into the complex chemistry of space billions of years ago. The material also contains a glint of white reflective material, which was initially thought to be calcium carbonate but was later found to be a fractured and broken crust with elements such as magnesium, sodium, and phosphate. The overall chemical composition of the samples closely resembles the ratio of elements seen in the Sun, confirming previous findings from rare meteorites and samples returned from Japan's mission to the asteroid Ryugu. The samples extracted so far are large enough to be studied by researchers worldwide. [Extracted from the article]

In the Solar System, extra-terrestrial organic molecules have been found on cometary primitive objects, on Titan and Enceladus icy moons and on Mars. Identification could be achieved for simple organic species by remote sensing based on spectroscopic methods. However in situ mass spectrometry is a key technology to determine the nature of more complex organic matter. A large panel of mass spectrometers has already been developed for space exploration combining different types of analysers and ion sources. Up to now the highest mass resolution reached with a space instrument is 9000 at m/z 28 and corresponds to the DFMS-ROSINA instrument (Balsiger et al., 2007) dedicated to the study of the comet 67P/Churyumov-Gerasimenko's atmosphere and ionosphere, in a low pressure environment. A new concept of mass analyser offering ultra-high mass resolving power of more than 50,000 at m/z 56 (under high vacuum condition about 10−9 mbar) is currently being developed for space applications: the CosmOrbitrap (Briois et al., 2016), based on the Orbitrap™ technology. This work challenges the use of LAb-CosmOrbitrap, a space instrument prototype combining Laser Ablation ionisation and the CosmOrbitrap mass analyser, to identify solid organic molecules of relevance to the future space exploration. For this purpose a blind test was jointly organised by the JAXA-HRMS team (Japan Aerospace Exploration Agency-High Resolution Mass Spectrometry) and the CosmOrbitrap consortium. The JAXA team provided two organic samples, whereas the CosmOrbitrap consortium analysed them without prior information. Thanks to the high analytical performances of the prototype and our HRMS data post-processing, we successfully identified the two molecules as HOBt, hydroxybenzotriazole (C 6 H 5 N 3 O) and BBOT, 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene (C 26 H 26 N 2 O 2 S), with a mass resolving power of, respectively, 123 540 and 69 219. The success of this blind test on complex organic molecules shows the strong potential of LAb-CosmOrbitrap for future space applications. • Efficient ionisation of solid sample by nano-pulsed single laser shot. • Powerful analytical performances of CosmOrbitrap mass analyser. • Successful blind test identification of organics ionised by Laser-CosmOrbitrap. • Laser-CosmOrbitrap relevant technique for space exploration of organic rich worlds. [ABSTRACT FROM AUTHOR]

Hyperbolic meteor orbits from the catalog of 64,650 meteors observed by the multistation video meteor network located in Japan (SonotaCo 2009) have been investigated with the aim of determining the relation between the frequency of hyperbolic and interstellar meteors. The proportion of hyperbolic meteors in the data decreased significantly (from 11.58% to 3.28%) after a selection of quality orbits, which shows its dependence on the quality of observations. Initially, the hyperbolic orbits were searched for meteors unbound due to planetary perturbation. It was determined that 22 meteors from the 7489 hyperbolic orbits in the catalog (and 2 from the selection of the orbits with the highest quality) had had a close encounter with a planet, none of which, however, produced essential changes in their orbits. Similarly, the fraction of hyperbolic orbits in the data, which could be hyperbolic by reason of a meteor's interstellar origin, was determined to be at most 3.9 × 10−2. From the statistical point of view, the vast majority of hyperbolic meteors in the database have definitely been caused by inaccuracy in the velocity determination. This fact does not necessarily assume great measurement errors, since, especially near the parabolic limit, a small error in the value of the heliocentric velocity of a meteor can create an artificial hyperbolic orbit that does not really exist. The results show that the remaining 96% of meteoroids with apparent hyperbolic orbits belong to the solar system meteoroid population. This is also supported by their high abundance (about 50%) among the meteor showers. [ABSTRACT FROM AUTHOR]

Although the Copernican hypothesis is popularized in Japan by Shiba Kōkan's books published between 1793 and 1805, the whole of the conceptions of the Occidental astronomy remains unknown at that time to most of the Japanese. Through the publication of Ensei kanshō zusetsu in 1823, Yoshio Nankō does achieve posthumously the project designed two years earlier by his young disciple, Kusano Yōjun, to spread this knowledge widely among the society. The book is a great and unprecedented success. Well known nowadays for its appendix (Chidō wakumon) and the influence that its content, while claiming the mobility of the Earth, did exert on the propagation of the heliocentrism in Japan until the very end of the Edo period, the book also provides as we think an unexpected and completely new platform for classical science, being the emissary of certain concepts invented by Shizuki Tadao from his relentless studies of Newtonian mechanics. Once we briefly recount Yoshio's career and discuss the sources and the morphology of his work, we give some arguments towards it. [ABSTRACT FROM AUTHOR]

Indoor solar-heating systems that use ventilated roofs have drawn attention in recent years. The effectiveness and efficiency of such air-heating systems vary depending on the design and operation methods. In Japan, by introducing outside air into a ventilated roof cavity and circulating the air indoors, systems that simultaneously obtain ventilation, solar heating, and heat-storage effects have been actively developed. The conventional systems intake a large volume of outside air to increase the solar heat collection effect. However, there is a risk of heat loss and over-drying when a large amount of cold dry air during winter is introduced. In this paper, plans are presented for improving these solar heating and heat-storage effects by preventing over-drying using indoor air circulation via ventilated cavities in the roof and indoor wall. By comparing the results of the proposed system with those of the conventional system via numerical simulation, the heating load is found to be reduced by 50% or more by circulating indoor air to the ventilated roof and storing the heat in the indoor wall. Moreover, an increased relative humidity of approximately 10% was confirmed by reducing the intrusion of the outside air and keeping the moisture indoors. [ABSTRACT FROM AUTHOR]

PHOTO (COLOR): A helicopter team followed a radio beacon to the Hayabusa2 return capsule hours after it landed in the Australian desert. But there is a puzzle: Ryugu appears to carry far less water than the otherwise similar asteroid Bennu, which is the target of a NASA sample return mission. [Extracted from the article]

To examine the effects of solar heat utilization, it is necessary to classify the solar-use climate in East Asia based on climatic factors that affect load reduction by solar heating systems. In this study, annual load simulations are performed on weather data in 842 sites in Japan to analyze the climatic factors that impact the load reduction effect of the solar heating system. The analysis results were based on three climatic factors that strongly affect the heating load of a building: heating degree day (HDD18-18), daily solar global horizontal irradiance, and solar-heat available days. Furthermore, to distinguish the climate for the use of solar heat in East Asia, climate classification was done according to three climatic factors using the weather data of 1176 sites in East Asia. Consequently, the climate of solar thermal utilization in East Asia can be classified into 88 areas. Based on the regional classification for solar heat utilization proposed in this study, it will be possible to examine the effect of load reduction and applicability according to the use of solar heat in each region in the future. [ABSTRACT FROM AUTHOR]

The article discusses research on the samples which were collected on the asteroid Itokawa by the Hayabusa spacecraft of the Japan Aerospace Exploration Agency (JAXA). Analysis of the mineralogy, petrography, and oxygen-isotope compositions of the asteroid showed that S-type asteroids are the parent bodies of chondritic meteors and provided information of the formation history of the asteroid, space weathering, and irradiation by cosmic rays. The article concludes that results from Hayabusa, as well as the Stardust and Genesis missions by the U.S. National Aeronautics and Space Administration (NASA), are important for studying the origin of the solar system.

Thermal anomaly detected by satellite before earthquake has been widely reported. Here we reported a new anomaly detected with geostationary satellite image. The geostationary satellite image series were combined together to make an animation, and it is found that the common cloud moved continuously, while the earthquake cloud stayed closely to the epicenter. Here an earthquake cloud example in Japan was reported. [ABSTRACT FROM AUTHOR]

The article presents information about the flight of Japanese spacecraft Hayabusa to asteroid 25143 Itokawa. It was the first spaceship to land on a near-Earth asteroid. It brought back clear images of the asteroid's surface and made several findings related to the mass and composition of the asteroid. The spacecraft was equipped with imaging camera, laser altimeter, near-infrared spectrometer and x-ray fluorescence spectrometer. The findings made by Hayabusa indicates that the asteroid is a chondritic rubble pile. It is composed rocks that new differentiated into core and mantle. The high resolution images of the surface of the asteroid shows fine gravels and boulders that are imbricated. The lumpy oblong shape of the asteroid has arisen from gravitational instabilities in which mass is shifted under repeated collissions with meteoroids. The spaceship has taken-off from the asteroid and its communication with Deep Space Control at the Institute of Space and Aeronautical Sciences of the Japan Aerospace Exploration Agency has been reestablished.

The article investigates the impact of the Japan's failure to collect a sample from a distant asteroid on its space program. The spacecraft Hayabusa has failed to collect sample from asteroid Itokawa. The country has merged its existing space agencies such as the National Space Development Agency, Institute of Space and Astronautical Science, and National Aerospace Laboratory. To improve its space program, politicians have asked the help of the U.S. and European space-agency chiefs.

The author discusses several articles published within the issue including one on the exchange of science ideas in Japan, another on the need to develop digital literacy, and another on the latest discoveries in the Solar System.

The article presents a new analysis of dust from the comet Wild 2, which was reported in the September 19, 2008 issue of the journal "Science" by researchers from Japan, NASA and the University of Wisconsin-Madison, who revealed that the dust comprises an oxygen isotope signature that suggests an interaction of rocky material between the center and edges of the solar system. The dust was collected in 2004 by the Stardust mission of NASA in an attempt to characterize the raw materials found in the solar system. It is mentioned that the new analysis will have an impact on theories of the history of the solar system.

This article reports that a tiny robotic rover intended to inspect the surface of the near-Earth asteroid Itokawa is drifting helplessly in space following a botched deployment. Dubbed Minerva, the rover was supposed to take images of the asteroid from which its parent craft, Hayabusa, will later collect rock samples. But a malfunction released Minerva 200 meters above the surface rather than the intended 60 meters, leaving it outside Itokawa's gravitational pull. Jun'ichiro Kawaguchi of the Japan Aerospace Exploration Agency, said that the agency hopes Hayabusa's descent close to the surface of Itokawa to release Minerva will pay off later this month when it attempts touchdowns to retrieve samples. Hayabusa is looking for clues about the composition of planetary bodies and how they have been transformed by "space weathering."

This article reports that the Japanese spacecraft Hayabusa arrived at near-Earth asteroid Itokawa on September 11, after traveling 28 months on a beam of high-speed ions. Hayabusa's ion-drive engine is just one part of a technologically ambitious attempt to bring home the first sample collected from an asteroid. So far, the ion drive and the laser-guided autonomous navigation have worked flawlessly. During the next several months, a robot named Minerva will be deployed to the surface. There, it should hop around taking pictures, because the 0.6-kilometer-long Itokawa's gravity is too feeble to work. Up to three times during the mission, Hayabusa itself will land momentarily to blast a sample into a collector for return to Earth in June 2007. Apparently, some sort of "space weathering" is reddening the surface of S-type asteroids.

Reports that Japan's most ambitious space mission entered a final, critical phase as the Hayabusa spacecraft parked itself 20 kilometers from the asteroid Itokawa. Return of samples of an asteroid to Earth; Description of the spacecraft.

We have been continuously observing the daily (7)Be concentrations in surface air at Yamagata, Japan (38.25 degrees N, 140.35 degrees E) since 2000. The yearly profile of the (7)Be concentration indicates the variation in galactic cosmic rays owing to solar modulation. Over 8y, the (7)Be concentration, cosmic neutrons, and number of sunspots varied by 37.4%, 12.2%, and 92.8%, respectively. The influence of precipitation on the (7)Be variability was approximately 5%. Hence, the yearly (7)Be concentration was mainly varied by the solar modulation of the (7)Be production rates. Based on the production rates found in an EXPACS simulation, the observed variability indicates (7)Be transport from high latitudes. The daily (7)Be concentrations have two significant periodic components of 19d and 36d. The 36-d component implies a relationship between the sun's rotation and the vertical transport of air masses under quiet solar activity.

Helio-geomagnetic influences on the human circulation are investigated on the basis of an 11-year-long record from a clinically healthy cardiologist, 35 years of age at the start of monitoring. He measured his blood pressure and heart rate around the clock with an ambulatory monitor programmed to inflate an arm cuff, mostly at intervals of 15-30 minutes, with only few interruptions, starting in August 1987. While monitoring is continuing, data collected up to July 1998 are analyzed herein by cosinor rhythmometry and cross-spectral coherence with matching records of solar activity, gauged by Wolf numbers (WN) and of the geomagnetic disturbance index, Kp. A direct association between heart rate (HR) and WN is found to be solar cycle stage-dependent, whereas an inverse relationship between heart rate variability (HRV) and WN is found consistently. An inverse relation is also observed between WN and the variability in systolic blood pressure (SBP), and to a lesser extent, diastolic blood pressure (DBP). Moreover, HR is cross-spectrally coherent with WN at a frequency of one cycle in about 7.33 months. The results support previously reported associations on morbidity and mortality statistics, extending their scope to human physiology monitored longitudinally.