Japanese Space Research Articles

항공우주자위대 창설을 통해 본 일본 우주정책의 변화와 전망

항공우주자위대 창설을 통해 본 일본 우주정책의 변화와 전망

From Madame Chrysanthème to Madame Prune: Triads and Tribulations in Pierre Loti’s Japanese Novels

Abstract The lack of scholarly interest in Pierre Loti’s second Japanese novel, La Troisième Jeunesse de Madame Prune (1905), has obscured the fact that it modifies our understanding of how Japan functions in the author’s imaginary. This article begins by offering a new reading of its better-known predecessor, Madame Chrysanthème (1887), concentrating on the insistent and proliferating use of triads. These structures involve characters (such as Loti–Yves–Chrysanthème), places (Loti–Nagasaki–Istanbul), and intertexts (Loti–Madame Chrysanthème–Le Mariage de Loti). Unlike in Eve Kosovsky Sedgwick’s and René Girard’s theoretical treatments of triangularity, Loti’s use of triads foregrounds the absence of desire, making Madame Chrysanthème an atypical novel in his corpus. Comparison with La Troisième Jeunesse de Madame Prune underlines this: in the later novel, Loti reinstates a fascination with both sexuality and mortality that was absent in its predecessor. Furthermore, because of its status as a sequel, it allows Loti’s use of nostalgia to gain in complexity, offering the coexistence of multiple temporalities in the same experience of the Japanese space.

Politics and space: Nakasone Yasuhiro and Japanese space programs

How does a country embark on large-scale R&D programs? Among R&D programs, this is an intriguing question for large scale Science and Technology (S&T) projects such as space programs, because of the necessity for large resource commitments, and the difficulty of being accountable to the taxpayers when the outcome is not always known.It can be assumed that engineers, scientists, bureaucrats, and politicians play respective roles. This paper aims to shed light on the specific role of politics, through the examples of policies of and decisions by NAKASONE Yasuhiro. Nakasone was the minister for science and technology (1959–1960, 1972), and later became the prime minister (1982–1987). He played a crucial role in establishing the Science and Technology Agency and the National Space Activities Council in the 1950s, which would be the foundational institutions responsible for space policy for the next half century. As prime minister, he decided to participate in the Space Station program.Within his vision for Japan for the 21st century, he emphasized the need for radical change in economic policy, education, defense and S&T investment. He was one of the few politicians that had vision to promote S&T and recognized the strategic value to the nation. He was able to explain to the nation why Japan should promote the development of a launch vehicle, when the engineers faced development difficulties in doing so. Thus, he was influential both in the policy layer and in promoting specific programs to support his national vision.Politics intersects with S&T projects because of the uncertainty and tradeoffs associated with these efforts. Japan did not address space programs for national security and commercial space for a long time. It is a politician's role to create institutions, to allocate resources and, more importantly, to explain to the taxpayers why policy measures or programs are necessary. R&D investment is a societal activity: it reflects the social, political, and economic situation, as well as being important for diplomacy and international relations. Bearing in mind that it would be misleading to attribute the initiation of largescale S&T projects to the leadership of a single individual, this paper will attempt to show the driving forces behind, and fundamental objective of Japan's space policy, in addition to the historical shift in that policy by examining the influence of this notable politician.

Austerity in Japanese Spaces

The purpose of this paper is to look at austerity present in Japanese culture spaces, such as Japanese gardens, Japanese interior design, which is minimalist, Japanese haiku poems settings, and their connection with Buddhist philosophy. The Japanese do not seem keen on accumulating objects. Instead, they prefer to keep their space minimal. The emptiness in Japanese Buddhist philosophy appears in interior design and garden design. Moreover, the Japanese focus more on their surroundings, for instance on contemplating the seasons and on their awareness of the changing seasons. Buddhist temples allow a large view of the landscape. Meanwhile, the interior design remains minimalist, and it also allows the inhabitant to be surrounded by empty space. The Japanese are not so much focused on accumulating objects during their lifetime as Westerners are. What could be such reasons? Why is their focus on the aesthetics of the surroundings? What could this tell us about Japanese culture that makes it unique?

Development of a new Phobos spectral simulant: spectral properties from visible to the mid-infrared range

ABSTRACT Phobos is the target of the Martian Moons eXploration (MMX), the next sample return mission of the Japanese space agency (JAXA). The mission will investigate the origin of Phobos and Deimos – the two martian moons, using a suite of dedicated instruments. Infrared analysis of the surface composition will be performed by the MIRS spectrometer onboard MMX. Within the scientific studies performed in preparation for the mission, we developed a new laboratory spectral simulant that well reproduces the red and featureless spectrum of Phobos. Our results show that a visible and near-infrared simulant can be developed using dark, opaque materials such as anthracite and coal to reduce the reflectance and absorption features. To investigate the reliability of our proposed simulant in terms of composition and mineralogy, we discussed the similarities and differences in the mid-infrared (MIR) range between our laboratory simulant and some past observations acquired on Phobos. Spectra with different observation geometries were also acquired for our simulant, which give information about grain size and textures of the surface. The simulant developed in our study presents a better match for the Phobos spectrum in the visible and near-infrared compared to the previously proposed simulants.

Phased Demonstrations of MBSE in Small Demonstration Satellite Series: Development of System Model and Environment for Full Application of MBSE

AbstractThe Japan Aerospace Exploration Agency (JAXA) has been implementing phased and progressive demonstrations of the Model‐Based Systems Engineering (MBSE) applications, using small demonstration satellite series, so called the Rapid Innovative Payload Demonstration Satellite (RAISE), as a demonstration pre‐cursor. The purpose of the activity is to establish a practical methodology of the MBSE application to satellite projects, to promote its practices, and to infuse MBSE to the Japanese space community. These RAISE satellites are 100kg‐class flagships in the Innovative Satellite Technology Demonstration Program, which provides on‐orbit demonstration opportunities for new technologies and key‐components. This paper presents the phased demonstration strategy, an overall approach, and the technology development of a system model being built for the full application of MBSE to RAISE‐4. For the technology development, the paper covers framework, modeling scope, system model building, system model collaboration with analysis/simulation tool, introduction of design rationale and concerns, information sharing through OpenMBEE, for our full application of MBSE.

Physical and ephemeral gestures in Japanese interior and their embodied potential to create a dialogue with nature

In order to search for a sustainable design that cares for a harmonious coexisting, the essay wanders through traditional Japanese space where an interior world opens up, that is able to shift our mindset to the essential of being, our focus away from a human-centred view towards a dialogue with nature. In the interior numerous clues bear a constant reminder of the natural world and confront us with gestures that carry a kindness and gentleness towards the environment. Space and its perception is here defined by the acknowledgement, that humans are part of the natural world, not superior. Can the way we are seated or the stone on a shelf embody a power to think about our environment differently? Can the floor transcend our knowledge of what we believe lies beneath our bare feet? This essay explores these gestures not only regarding a mere physical character but outlines the transcendental and intangible, narrations that transcend time and knowledge with the potential to reposition the monologue of the human towards a dialogue with nature. It looks at them as potential of “Dasein,” as motor for change—to overcome the standing dichotomy between the natural world and the human.

Organic detection in the near-infrared spectral Phobos regolith laboratory analogue in preparation for the Martian Moon eXploration mission

Context.The Martian Moon eXploration mission (MMX) of the Japanese space agency (JAXA) is scheduled to take off in September 2024 to explore Phobos and Deimos – the two martian moons – by in situ observations, but also by a sampling and returning regolith samples to Earth. The origins of Phobos and Deimos are still unknown and their understanding is one of the main goals of the MMX mission. In one scenario, Phobos could be a captured asteroid, as the Phobos spectrum is similar to dark D-type asteroids.Aims.For the present work, we considered the hypothesis of Phobos being a captured D-type asteroid, and we investigated the detectability of organics on Phobos using laboratory spectral analogues.Methods.We synthesised a near-infrared spectral analogue of Phobos composed of olivine (77 vol.%, 50–125 µm), hyperfine anthracite (20 vol.%, <1 µm), and organic tholins (3 vol.%, ~400 nm) by measuring the reflectance spectrum from 0.4 to 4.75 µm with the SHADOWS spectrogonio-radiometre developped at IPAG. The best spectral match for a Phobos regolith analogue was chosen based on its reflectance level and spectral slope similarities to Phobos’ observed spectrum. Several samples were then prepared by adding a different volume content of organic matter (Titan tholins). We monitored the 3 µm band attributed toN-Hbands stretching modes absorption due to the amine function in the tholins, so as to assess the detectability of the NH-rich organics on Phobos.Results.We have demonstrated that the organic compounds become detectable for more than 5 vol.% in the mixture. We further studied the observation geometry effects on the absorption band depth and found no significant effect except at large phase angles (>80º). These results will be useful to interpret the data of the MMX Infrared Spectrometer (MIRS) onboard the MMX spacecraft, which will measure the spectral reflectance of Phobos from 0.9 to 3.6 µm.

Recovering the Elusive Spectral Width From Spaceborne Doppler Profiling Radar Measurements: The “ExpliSyT” Approach

This article presents a novel method to retrieve spectral widths from measurements of spaceborne Doppler profiling radars operating in low-Earth orbit. The proposed “ExpliSyT” approach, is based on a formulation of the Doppler broadening in terms of the distributions of reflectivity and velocity in the footprint. This formulation makes it possible to estimate the broadening and remove it from the spectral-width measurement. Two implementations of the ExpliSyT correction are described: 1) a numerical implementation that uses Wiener’s deconvolution, and 2) an analytical implementation based on Taylor expansions of the radar observations. The ExpliSyT corrections enable retrievals of higher-order Doppler information such as posterior power spectra. Results are shown for simulations of the radar of EarthCARE (Earth Cloud Aerosol Radiation Explorer developed by the European and Japanese space agencies) and a Displaced Phase Center Antenna (DPCA) configuration, for which the ExpliSyT corrections perform significantly better. A novel <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">canonical Doppler resampling diagram</i> is introduced to explain the correlation between non-uniform beamfilling (NUBF) and spectral broadening. This tool shows that 1) the NUBF of reflectivity modulates the spacecraft-induced spectral broadening, and 2) the NUBF of velocity can either broaden or <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">shrink</i> the Doppler spectrum. This spectral shrinkage, although important, is not typically thought of when dealing with spaceborne Doppler radars. The ability to estimate spectral widths accurately from space paves the way for future microphysical and dynamical characterizations of hydrometeors in shear or turbulence.

Similarities between Disaster Food and Space Food.

Disaster and space environments are similar in that they are closed environment, with limited lifelines. Here, we examined the similarity between disaster food and space food, to explore interactive problem-solving of food support for disaster and space environments. The Japan Disaster Food Certification Standards (Japan Disaster Food Society) and the Japanese Space Food Certification Standards (Japan Aerospace Exploration Agency) requirements and certified products, which were posted on the websites as of June 16, 2021, were compared. Certified products were classified into "staple foods," "main and/or side dishes," "milk and dairy products," "fruits," "confectionery and favorite beverages," "condiments," "dietary supplements," and "sets." Certification standards involved six items for Japan Disaster Food and eight items for Japanese Space Food. Most standards were similar. Concretely, both standards demanded room temperature storage, tough packaging and hygiene management in facilities. Both emphasized habitual food and easy eating. However, the best-by date was ≥6 mo for Japan Disaster Food, but ≥1.5 y for Japanese Space Food. In addition, Japanese Space Food required noted nutritious, food hygienic, eatable in space, cookable by specific equipment, endurable pressure by launch, and domestically produced food. There were 171 and 47 products of Japan Disaster Food and Japanese Space Food, respectively. Staple foods (pregelatinized rice, etc.) and main and/or side dishes were commonest among Japan Disaster Foods and Japanese Space Foods, respectively. It is possible to utilize of Space Food as Disaster Food, but there are some issues that must be cleared before "utilization of Disaster Food as Space Food."

DECi-hertz Interferometer Gravitational-wave Observatory: Forecast Constraints on the Cosmic Curvature with LSST Strong Lenses

Abstract In this paper, we aim to use the DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO), a future Japanese space gravitational-wave antenna sensitive to the frequency range between LISA and ground-based detectors, to provide gravitational-wave constraints on the cosmic curvature at z ∼ 5. In the framework of the well-known distance sum rule, the perfect redshift coverage of the standard sirens observed by DECIGO, compared with lensing observations including the source and lens from LSST, makes such cosmological-model-independent tests more natural and general. Focusing on three kinds of spherically symmetric mass distributions for the lensing galaxies, we find that the cosmic curvature is expected to be constrained with the precision of ΔΩ K ∼ 10−2 in the early universe (z ∼ 5.0), improving the sensitivity of ET constraints by about a factor of 10. However, in order to investigate this further, the mass-density profiles of early-type galaxies should be properly taken into account. Specifically, our analysis demonstrates the strong degeneracy between the spatial curvature and the lens parameters, especially the redshift evolution of the power-law lens index parameter. When the extended power-law mass-density profile is assumed, the weakest constraint on the cosmic curvature can be obtained, whereas the addition of DECIGO to the combination of LSST+DECIGO does improve significantly the constraint on the luminosity–density slope and the anisotropy of the stellar velocity dispersion. Therefore, our paper highlights the benefits of synergies between DECIGO and LSST in constraining new physics beyond the standard model, which could manifest themselves through accurate determination of the cosmic curvature.

Between the Rocket and the Deep Blue Sea:Local Resistance and Reconciliation to Japanese Space Facilities, 1945‒2003

Between the Rocket and the Deep Blue Sea:Local Resistance and Reconciliation to Japanese Space Facilities, 1945‒2003

Dynamic Retrievals From Spaceborne Doppler Radar Measurements: The CConDoR Approach

This article presents a new method to retrieve dynamic information from spaceborne Doppler radar observations. The method is based on a Complex Convolution Doppler Resampling (CConDoR) formulation, which links the spaceborne pulse-pair correlation measurements to high-resolution pulse-pair products that are not affected by the spacecraft motion. The CConDoR formalism allows to easily simulate Doppler products (forward simulations) via convolution products. The CConDoR representation enables also retrievals by complex deconvolution. This approach is illustrated using a Wiener deconvolution algorithm. Results are shown for simulations of EarthCARE&#x2019;s (Earth Cloud Aerosol Radiation Explorer developed by the European and Japanese space agencies) radar. The proposed corrections improve the accuracy of the measured mean velocities (by correcting for non-uniform beam-filling biases) and spectral widths (by correcting for the spectral broadening, which to the best of the Authors&#x2019; knowledge is novel).

Comparing Japanese and US Language Spaces: A Case Study

Language spaces worldwide have much in common. However, we believe that there is a meaningful difference between spaces that are considered “language centers” in the US (USLCs) and “self-access language centers” (SALCs) in Japan. These differences provide an opportunity for practitioners and scholars involved in language spaces to learn from each other. In the current article, we investigated the Global Commons at Kyoto Sangyo University for the characteristics of both USLCs and SALCs by collecting information about it from publicly available sources and from interviews with staff. We show that it can be considered an administrative SALC (Mynard, 2019) and show how it fulfills some of the USLC mandates (Lavolette, 2018) but not others. We discuss the implications of these characterizations, including how the Global Commons could be more useful to its stakeholders. Based on this case study, scholars of both SALCs and LCs can gain new ideas for services and roles that will benefit their stakeholders and facilitate change.

Mission to Mercury

On 1 October 2021 at 23.34 UTC, the BepiColombo mission – a joint project by the European and Japanese space agencies – carried out the first of six Mercury fly-bys. These fly-bys are needed so that the spacecraft can match its velocity with the planet’s, allowing it to be captured into orbit about Mercury in […]

Japan and the West: An Architectural Dialogue

Japan and the West: An Architectural Dialogue

Overview of act on launching of spacecraft, etc. and control of spacecraft in Japan

The Japanese Act on Launching of Spacecraft, etc. and Control of Spacecraft (commonly cited as “Space Activity Law”) and related documents came into force on November 15, 2018.To implement UN treaty obligations related to outer space accurately and smoothly, to ensure public safety, and to contribute to enhancing the livelihood of people and the development of the economy, Japan established a system related to launch, launch vehicles, control of spacecraft and a compensation scheme for damage to third parties caused by the launch of a launch vehicle.In addition to the Japanese Space Activity Law, there are many other international “space activity laws”. In order to update and harmonize the Japanese Space Activity Law with international space law, the National Space Policy Secretariat (NSPS) conducted an investigation of international and national space laws, especially the United Kingdom, France and United States of America through both documentary research and in-person meetings.This paper provides an overview of the Japanese Space Activity Law.

Thermal analysis and constraints for the MASCOT landing site selection on the Asteroid Ryugu

In June 2018, after 4 years of cruise, the Japanese space probe Hayabusa2 [1-Watanabe S. et al.: Hayabusa2 Mission Overview. (2017)] reached the Near-Earth Asteroid (162173) Ryugu. Hayabusa2 carried a small Lander named MASCOT (Mobile Asteroid Surface Scout) [2-Ho T. M. et al.: MASCOT-The Mobile Asteroid Surface Scout on-board the Hayabusa2 mission. (2017)], jointly developed by the German Aerospace Center (DLR) and the French Space Agency (CNES), to investigate Ryugu's surface structure, composition and physical properties including its thermal behaviour and magnetization in-situ. The Microgravity User Support Centre (DLR-MUSC) in Cologne was in charge of providing all thermal conditions and constraints necessary for the selection of the final landing site and for the final operations of the Lander MASCOT on the surface of the asteroid Ryugu.This article provides a comprehensive assessment of these thermal conditions and constraints, based on predictions performed with the Thermal Mathematical Model (TMM) of MASCOT using different asteroid surface thermal models, ephemeris data for approach as well as descent and hopping trajectories, the related operation sequences and scenarios and the possible environmental conditions driven by the Hayabusa2 spacecraft.A comparison with the real telemetry data confirms the analysis and provides further information about the asteroid characteristics.

Characterising atmospheric gravity waves on the nightside lower clouds of Venus: a systematic analysis

We present the detection and characterisation of mesoscale waves on the lower clouds of Venus using images from the Visible Infrared Thermal Imaging Spectrometer onboard the European Venus Express space mission and from the 2 μm camera (IR2) instrument onboard the Japanese space mission Akatsuki. We used image navigation and processing techniques based on contrast enhancement and geometrical projections to characterise morphological properties of the detected waves, such as horizontal wavelength and the relative optical thickness drop between crests and troughs. Additionally, we performed phase velocity and trajectory tracking of wave packets. We combined these observations to derive other properties of the waves such as the vertical wavelength of detected packets. Our observations include 13 months of data from August 2007 to October 2008, and the entire available data set of IR2 from January to November 2016. We characterised almost 300 wave packets across more than 5500 images over a broad region of the globe of Venus. Our results show a wide range of properties and are not only consistent with previous observations but also expand upon them, taking advantage of two instruments that target the same cloud layer of Venus across multiple periods. In general, waves observed on the nightside lower cloud are of a larger scale than the gravity waves reported in the upper cloud. This paper is intended to provide a more in-depth view of atmospheric gravity waves on the lower cloud and enable follow-up works on their influence in the general circulation of Venus.

Current status of space gravitational wave antenna DECIGO and B-DECIGO

Abstract The Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) is a future Japanese space mission with a frequency band of 0.1 Hz to 10 Hz. DECIGO aims at the detection of primordial gravitational waves, which could have been produced during the inflationary period right after the birth of the Universe. There are many other scientific objectives of DECIGO, including the direct measurement of the acceleration of the expansion of the Universe, and reliable and accurate predictions of the timing and locations of neutron star/black hole binary coalescences. DECIGO consists of four clusters of observatories placed in heliocentric orbit. Each cluster consists of three spacecraft, which form three Fabry–Pérot Michelson interferometers with an arm length of 1000 km. Three DECIGO clusters will be placed far from each other, and the fourth will be placed in the same position as one of the other three to obtain correlation signals for the detection of primordial gravitational waves. We plan to launch B-DECIGO, which is a scientific pathfinder for DECIGO, before DECIGO in the 2030s to demonstrate the technologies required for DECIGO, as well as to obtain fruitful scientific results to further expand multi-messenger astronomy.