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Analyses of measurements made by MERTIS1 (MErcury Radiometer and Thermal Infrared Spectrometer) during the BepiColombo mission's close flyby 2 of Venus (FB2) have already demonstrated the instrument's capacity to explore the planet's mesosphere at near equatorial latitudes. The MERTIS instrument was designed to study the hot surface of Mercury. It performed well beyond its design limits when analyzing the Venusian mesosphere because of the much lower radiances. MERTIS’ measurements are the first spectrally resolved observations of Venus in the thermal spectral range longward of 5 µm since the Venera-15 Fourier spectrometer experiment in 19832. It could be shown that MERTIS FB2 data enable reliable retrievals of mesospheric temperature profiles and cloud parameters between 60 and 75 km altitude. They are in good agreement with the results of the Venera-15 mission. This indicates the stability of the Venusian atmosphere on time scales of decades3,4.In this paper we discuss preliminary results from MERTIS measurements of the first flyby (FB1) in October 2020. During the first flyby the spacecraft approached the planet from the solar direction over the dayside. The closest approach (CA) occurred at about 11,000 km distance above the evening terminator of the planet, and then the spacecraft moved away from the planet to the anti-solar direction. In this time the apparent size of Venus increased from slightly larger than one MERTIS pixel (0.7 mrad) to more than 1 degree. MERTIS performed close-up dayside observations from early morning to late afternoon via noon time on Venus at latitudes between 50°S and 85°N and obtained about 785,000 hyperspectral observations with the spectrometer channel. Thus, FB1 observations permit much larger latitude coverage from 50°S to 85°N compared to FB2. To process the FB1 data in terms of both a reasonable signal-to-noise ratio and comparable observing conditions, individual spectra were averaged over 5° latitude belts and 0.5 h local time intervals. We further excluded extreme observation geometries for latitudes northward of 80°N and southward of 40°S as well as very weak spectra. As a result, we are able to generate a reliable data base for use in radiative transfer analyses for the Venusian mesosphere. We present preliminary results on the temperature fields of the mesosphere as a function of local time, altitude, and latitude. Hiesinger, H. et al. Space Sci. Rev. 216, 6 (2020).Oertel, D. et al. Adv. Space Res. 5, 25-36 (1985).Arnold, G. et al., SPIE Optic+Photonics, San Diego, Proceedings Volume 12233, doi.org/10.1117/12.2632548 (2022).Helbert, J. et al. submitted to Nature Astronomy (2023).

Sustainability and the concept of circular economy are two of the most prominent approaches in the fashion industry to meet global challenges. Advocated by different interest groups, these concepts primarily follow an environmental and economic perspective on sustainability. In turn, the social dimension of sustainability has not been extensively explored. Performing a comparative discourse analysis, this study triangulates data from three different perspectives and unveils social sustainability-related aspects in documents related to two specific companies as well as in academic and stakeholder publications in the fashion context. We use LeximancerTM to reveal and visualize the scope and frequency of socially relevant concepts in more than 550 publications. Based on this, results show that the two fashion companies have gradually been communicating more about social sustainability-related aspects as opposed to academic and stakeholder publications. Overall, single social sustainability-related values exclusively appear in each of the publication groups, whereas others seem to reflect a mutual influence among the different players. Yet, pivotal social sustainability-related issues are missing. This corroborates scholars assuming a neglected role of the social dimension of sustainability in general and calling for a greater elaboration on social aspects in the conceptualization of a circular economy. Our results also call for a deeper follow-up analysis of communications, practices and strategies of different actors in their respective social contexts.

Purpose Service learning is not comprehensively developed in economics such as the implementation of the 17 sustainability goals of the Agenda 2030 – although this would be beneficial as experiential learning is linked to democratic education goals. Service Learning offers itself as a didactic design for this purpose. The paper aims to discuss how service learning can be used to work critically and reflexively on sustainability issues in a cross-university context. Design/methodology/approach The cross-university teaching-learning project brought together students of industrial engineering and economics. The idea space “sustainable city” was to be developed together with practice partners with the help of the practice-relevant project management method scrum and methods of sustainability assessment in the sense of service learning. Evaluating the project, a written and a qualitative survey were conducted and analysed by means of descriptive statistics as well as content analysis. Findings Success factors include the regular feedback by practice partners and lecturers including reflection questions. Student heterogeneity can hinder effective project work. Complexity can deter effective and successful service learning. The use of scrum in service learning contexts cannot be fully recommended. Although scrum contributes to service learning concepts in economics, in complex sustainability projects either the method should be in focus or prior knowledge of scrum should be mandatory. Originality/value The paper discusses how service learning can be used to critically and reflexively address social and practical challenges in a cross-university context. The study contributes to the fact that the complexity of education for sustainable development competencies requires the teaching of knowledge- and fact-based fundamentals as well as methodological-research procedures for research-based and at the same time practice-oriented learning.

The global social, economic, and ecological sustainability challenges are immense, particularly in Africa. Given the continent's specific characteristics, there is a strong need to either shape “traditional” business models or to consider alternative corporate strategies. Those should in particular foster social change and progress through economic development. Social entrepreneurship is regarded as such an alternative approach. In addition, stronger aligning firms' business models to CSR dimensions as laid out in international standards such as ISO 26000 might be a valuable trajectory. By using an exploratory comparative case design and qualitatively analyzing the websites of four African textile companies, this chapter illustrates how social sustainability is being pursued. The findings suggest that sustainability-oriented textile companies strongly emphasize social sustainability, in particular labor practices, community involvement, and development. This enables further research on drivers and implications for sustainability marketing strategies in global textile value chains.

1. Introduction Thermal infrared datasets from planetary bodies have the potential to provide key insights for the understanding of a planet's climate evolution and history: valuable information about composition, temperature and state of the atmosphere can be retrieved from thermal spectral data.In this work, we present the application of a methodology based on Principal Component Analysis (PCA) and Target Transformation (TT) Factor Analysis (FA) techniques to thermal infrared data of the ExoMars2016 Trace Gas Orbiter (TGO) with the main goal to retrieve the different particulate atmospheric contributions present in the spectra and separate them from the surface contributions. 2. Instrument and dataset TGO has a suite of spectroscopic instruments for the investigation of the Red Planet in the infrared spectral range known as Atmospheric Chemistry Suite (ACS) [1] consisting of three spectrometers observing Mars in solar occultation, nadir and limb geometry in the Near-InfraRed (NIR), Mid-InfraRed (MIR) and Thermal InfraRed (TIR) spectral channels. Among them, the ACS thermal-infrared channel (TIRVIM) covers the spectral range between 1.7-17 μm with apodized resolution varying from 0.2 to 1.3 cm−1 [1]. TIRVIM has similar capabilities to IRIS (Mariner 9), TES, and PFS in several aspects, but has some advantages: - higher spectral resolution; - better noise equivalent radiance (from 0.08 mW/m2/sr-1/cm-1); - dense spatial coverage (TGO has a circular orbit of 400 km) [1].Martian TIRVIM spectra acquired along the orbits that cross Elysium Planitia, landing site of the NASA’s Insight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) lander, were here analyzed. The selected data orbits span from Ls=150°C to Ls=210°C, covering part of the Martian summer and of the Martian autumn going through the autumn equinox in the northern hemisphere of the planet. Corresponding Local Times cover Martian days and nights. 3. Methodology To analyze the ExoMars TIRVIM data and retrieve and characterize the number of varying atmospheric components present in these data and their spectral shape, a methodology was applied based on a combination of PCA and TT – FA techniques [2, 3]. These techniques are demonstrated to be able to extract the composition of laboratory samples [4, 5]; to extract the principal varying components from a big spectral dataset in the thermal infrared [3], and then to identify them as components of the atmosphere and separate their contribution from surface emission [6]. This methodology, previously successfully adopted for the analysis of TES and PFS data [2, 7], was, here, applied for the first time to the analysis of the new and at higher spectral resolution TIRVIM dataset. Considering that the PCA works best when the different components have significant variation in the data, we selected data where these variations are more likely to occur: the analyzed data cover diurnal as well as seasonal variations. A list of PFS and TES atmospheric end-members extracted from [3] and [2] were used as initial guess for the TT, to interpret the abstract eigenvectors retrieved from the PCA and attribute them a physically coherent meaning. 4. Results and future developments Spectral shapes of atmospheric dust and water ice aerosols were recovered from the analyzed TIRVIM data. Comparisons with results previously obtained on PFS and TES data (Figure 1) validate the methodology used and show that it is capable of determining the number of independently variable components and recovering the spectral endmembers present in the TIRVIM data. Figure 1. Comparison between the general TES/PFS extracted endmembers [2, 3] (upper panel) and the endmembers extracted from the TIRVIM data in this work (bottom panel). Grey area: wavelength cut due to high instrumental noise. Deconvolution of the original spectra using the recovered spectral end-members allowed us to obtain the concentration coefficients of the dust and water ice end-members and retrieved abundances maps. The results obtained are promising in terms of identification and separation of the atmospheric components and have strong impact on the identification of surface contributions in the spectra. We are further investigating this point with the main goal of showing the potential of this method to extract valuable information from TIRVIM data not only on the atmosphere, but also on the surface of the Red Planet. Derived surface emissivity products are being analyzed by linear deconvolution analysis with the laboratory spectral database of Martian analogues measured at the Planetary Spectroscopy Laboratory (PSL) of DLR, in Berlin [5]. Acknowledgments ExoMars is a space mission of ESA and Roscosmos. The ACS experiment is led by IKI, the Space Research Institute in Moscow, assisted by LATMOS in France. The science operations of ACS are funded by Roscosmos and ESA. References [1] Korablev et al. (2018) Space Science Review, 214:7. [2] D’Amore M. et al. (2013) Icarus, 226, 1294-1303. [3] Bandfield J.L., Christensen P.R., Smith M.D. (2000) JGR, 105 (E4), 9573-9587. [4] Smith, M.O., Adams, J.B., Johnson, P.E. (1985) JGR, 90, 797-804. [5] Alemanno G., Maturilli A., D’Amore M., Helbert J. (2021) Icarus, 368. [6] Smith M. D., Bandfield J. L. and Christensen P.R. (2000) JGR, 85 (E4), 9589-9607. [7] Maturilli, A., Helbert, J., D’Amore, M. (2009) EPSC2009, Abstract #EPSC2009-106.

Introduction The MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS) onboard BepiColombo is designed to study and map Mercury surface mineralogy and temperatures. It combines an imaging push-broom infrared spectrometer (TIS, 7-14 µm) with a radiometer (TIR, 7-40 µm) that share the same in-flight optics, electronics, and calibration unit [1]. During the two Venus flybys of BepiColombo spacecraft in October 2020 and August 2021, MERTIS-TIS acquired several hundred thousand spectra in the mid-infrared range with spectral resolution down to 90 nm [2, 3, 4]. The MERTIS measurements were the first spectrally resolved observations of Venus in the mid-IR range since the Venera 15 mission in 1983 [8]. We report on the results of MERTIS mid IR measurements and show average brightness temperature spectra. Basing on a multi-channel radiative transfer simulation and retrieval algorithm we extract atmospheric temperature profiles and cloud parameters of Venus’ upper troposphere and mesosphere. Method A multi-channel radiative transfer simulation and retrieval algorithm has been adapted to investigate MERTIS-TIS data and to extract atmospheric temperature altitude profiles and cloud mode factors MF1/2 of Venus’ atmosphere. The Radiative Transfer Model (RTM) includes the discrete ordinate package DISORT [5]. It considers absorption, emission, and multiple scattering by gaseous and particulate atmospheric constituents and makes simultaneous use of information from different spectral ranges of an individual spectrum [6,7]. Mesospheric temperature profiles are retrieved using Smith’s relaxation method [8]. It employs initial and measured brightness temperatures in the 15 µm CO2 band. The results of the MERTIS measurements were compared with mid-infrared data recorded by the FS-1/4 spectrometer (PMV) aboard the Venera-15 mission in 1983 [8]. Results We show that Venusian mesospheric parameters like temperature profiles and cloud properties can reliable determined from MERTIS flyby data (Fig. A). The short-wave edge of the 15-µm CO2 band was used to determine atmospheric temperature profiles in an altitude range of about 58-77 km (Fig. B). The retrieved temperature profiles well agree both with VIRA [9] and corresponding profiles obtained from Venera 15 PMV data. Atmospheric cloud factors were investigated from MERTIS spectral data around 10 µm. They are also well coinciding with earlier analyses. Still ongoing refinements of calibration will allow the use of data between 7 and 10 μm for the analysis of further atmospheric properties. Fig. MERTIS-TIS FB2, A: Comparison of measured and simulated MERTIS brightness temperature spectra, B: Comparison of initial and retrieved temperature profiles. References [1] Hiesinger, H. and Helbert, J., Planet. Space Sci. 58, (2010). [2] Maturilli, A., et al., 52nd LPSC, 1435, (2021). [3] Helbert, H., et al., 52nd LPSC, 1521, (2021). [4] Arnold, G., et al., SPIE Optics+Photonics, IR Remote Sensing and Instrumentation XXIX, 1183009, (2021). [5] Stamnes, K. et al., Appl.Opt. (12), 2502-2509, (1988). [6] Haus, R., Kappel, D., Arnold, G., Icarus 232C, 232-248, (2014) [7] Haus, R., Kappel, D., Arnold, G., Planet. Space Sci. 89, 77-101, (2013). [8] Smith, W.L., Appl. Opt.9(9), 1993-1999, (1970). [8] Oertel, R. et al., Adv. Space Res. 5(9), 25-36, (1985). [9] Zasova, L.V. et al., Cosmic Res. 44(4), 364-383, (2006).

It is currently uncertain as to whether methane exists on Mars. Data from the Curiosity Rover suggests abackground methane concentration of a few tenths parts per billion whereas data from the Trace Gas Orbitersuggest an upper limit of twenty parts per trillion. If methane exists on Mars then we do not understand fully thephysical and chemical processes affecting its lifetime. Atmospheric models suggest an over-estimate in thelifetime by a factor of around six hundred compared with earlier observations. In the present work we assume theCuriosity Rover background methane value and estimate the uncertainty in atmospheric chemistry and mixingprocesses in our atmospheric column model 1D TERRA. Results suggest that these processes can only explain afactor of ~sixteen lowering in the methane lifetime. This implies that if methane is present then additional,currently unknown processes are required to explain the observed lifetime.

The EU Textile Strategy for Sustainable and Circular Textiles calls for circularity along the whole value chain of textiles. However, little is known about how circularity is already embedded in German manufacturing textile industries due to a lack of literature. Having conducted a survey study in December 2022 and January 2023, the results of 56 participating German manufacturing textile industries will be presented by applying descriptive statistics and qualitative analysis. The study shows that there is already an understanding of circularity including circular strategies in the German textile manufacturing industry. There are companies that apply the following circular business model strategies: upcycling and recycling, product-as-a-service, repair and reuse, and material innovation. Closed-loop supply chain companies are not yet prominent. Many manufacturing textile companies are not prepared yet for a circular transformation. Another finding is that the EU Strategy for Sustainable and Circular Textiles is so far insufficiently known by the respondents of the sample. A more structured provision of information or financial state support should be discussed.

Comets evolve due to sublimation of ices embedded inside porous dust, triggering dust emission (that is, erosion) followed by mass loss, mass redistribution and surface modifications. Surface changes were revealed by the Deep Impact and Stardust NExT missions for comet 9P/Tempel 1 (ref. 1), and a full inventory of the processes modifying cometary nuclei was provided by Rosetta while it escorted comet 67P/Churyumov–Gerasimenko for approximately two years2–4. Such observations also showed puzzling water-ice-rich spots that stood out as patches optically brighter and spectrally bluer than the average cometary surface5–9. These are up to tens of metres large and indicate macroscopic compositional dishomogeneities apparently in contrast with the structural homogeneity above centimetre scales of pebble-made nuclei10. Here we show that the occurrence of blue patches determines the seasonal variability of the nucleus colour4,11,12 and gives insight into the internal structure of comets. We define a new model that links the centimetre-sized pebbles composing the nucleus10 and driving cometary activity13,14 to metre-sized water-ice-enriched blocks embedded in a drier matrix. The emergence of blue patches is due to the matrix erosion driven by CO2-ice sublimation that exposes the water-ice-enriched blocks, which in turn are eroded by water-ice sublimation when exposed to sunlight. Our model explains the observed seasonal evolution of the nucleus and reconciles the available data at micro (sub-centimetre) and macro (metre) scales.

Remote sensing data of comets 9P/Tempel 1 and 67P/Churyumov-Gerasimenko (67P hereafter) indicate the occurrence of water-ice-rich spots on the surface of cometary nuclei [1-5]. These spots are up to tens of metres in size and appear brighter and bluer than the average surface at visible wavelengths. In addition, the extensive observation campaign performed by the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS, [6]) and the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS, [7]) during the Rosetta escort phase at 67P revealed a seasonal cycle of the nucleus colour. This is characterised by blueing of the surface while approaching perihelion followed by progressive reddening and restoral of the original colour along the outbound orbit. The temporal evolution of the colour has been interpreted in previous studies as the result of increasing exposure of water ice at smaller heliocentric distances [8, 9], however, an explanation of such seasonal cycle in the context of a quantitative cometary activity model was not yet been provided. Recently, in [10] we showed that the seasonal colour cycle observed on comet 67P is determined by the occurrence of the above-mentioned water-ice-rich spots (referred to as Blue Patches – BPs –, given their colour). This can be explained in the context of activity models [11, 12] of pebble-made cometary nuclei [13], i.e. in terms of nucleus surface erosion induced by H2O and CO2 ices sublimation, driving the cometary activity. According to the scenario proposed in [10] (Fig. 1), the presence of the BPs is due to the exposure of subsurface sub-metre-sized Water-ice-Enriched Blocks (WEBs) thanks to surface erosion triggered by CO2 sublimation ejecting decimetre-sized chunks [12]. The WEBs are composed of ice-rich pebbles (dust-to-ice mass ratio δ=2, [14]), embedded in a matrix of drier pebbles (δ>>5) forming most of the nucleus. Once exposed to illumination as BPs, the WEBs are eroded by water-ice sublimation ejecting sub-cm dust [11]. By means of dedicated spectral and thermophysical modelling, we match the nucleus colour temporal evolution measured by the VIRTIS Mapping channel in the 0.55-0.8 µm spectral range. In doing this, we take into account the competing effects of CO2- and H2O-driven erosion that expose and remove the BPs, respectively, and are seasonally modulated by the insolation conditions, primarily depending on the heliocentric distance. The new nucleus model proposed in [10], implying an uneven distribution of water ice in cometary nuclei, reconciles the compositional dishomogeneities observed on comets (the BPs) at macroscopic (up to tens of metres) scale, with a structurally homogeneous pebble-made nucleus at small (centimetre) scale, and with the processes determining the cometary activity at microscopic (sub-pebble) scales. Figure 1. 67P surface gets bluer approaching perihelion as a consequence of the progressive exposure to sunlight of subsurface WEBs (from Figure 4 in Ciarniello et al., 2022, Nature Astronomy, https://doi.org/10.1038/s41550-022-01625-y). The comet nucleus is made of two types of pebbles, both including refractories and CO2 ice, with different water ice content: pebbles with high content of H2O ice form the WEBs, while H2O-ice-poor pebbles represent the rest of the nucleus. CO2 ice is stable beneath the CO2 sublimation front at depths >0.1 m [12]. Approaching perihelion, the CO2 ice sublimation rate increases, eroding the surface by chunk ejection and exposing the WEBs. Once exposed, WEBs lose CO2 and are observable as BPs. Water-ice sublimation erodes the BPs ejecting sub-cm dust from their surface and preventing the formation of a dry crust [11]. The BPs survive until their water-ice fraction is sublimated, producing the observed surface blueing. Please refer to ref. [10] for complete details. References [1] Sunshine, J. M. et al. (2006) Science 311, 1453–1455. [2] Filacchione, G. et al. (2016) Nature 529, 368–372. [3] Raponi, A. et al. (2016) Mon. Not. R. Astron. Soc. 462, S476-S490. [4] Barucci, M. A. et al. (2016) Astron. Astrophys. 595, A102. [5] Oklay, N. et al. (2017) Mon. Not. R. Astron. Soc. 469, S582–S597. [6] Coradini, A. et al. (2007) Space Sci. Rev. 128, 529–559. [7] Keller, H. U. et al. (2007) Space Sci. Rev. 128, 433–506. [8] Fornasier, S. et al. (2016) Science 354, 1566–1570. [9] Filacchione, G. et al. (2020) Nature 578, 49-52. [10] Ciarniello, M. et al. (2022) Nat. Astron. doi:10.1038/s41550-022-01625-y. [11] Fulle, M. et al. (2020) Mon. Not. R. Astron. Soc. 493, 4039–4044. [12] Gundlach, B. et al (2020). Mon. Not. R. Astron. Soc. 493, 3690–3715. [13] Blum, J. et al. (2017) Mon. Not. R. Astron. Soc. 469, S755–S77. [14] O’Rourke, L. et al. (2020) Nature 586, 697–701. Acknowledgements We thank the Italian Space Agency (ASI, Italy; ASI-INAF agreements I/032/05/0 and I/024/12/0), Centre National d’Etudes Spatiales (CNES, France), and Deutsches Zentrum für Luft-und Raumfahrt (DLR, Germany) for supporting this work. VIRTIS was built by a consortium from Italy, France and Germany, under the scientific responsibility of IAPS, Istituto di Astrofisica e Planetologia Spaziali of INAF, Rome, which also led the scientific operations. The VIRTIS instrument development for ESA has been funded and managed by ASI (Italy), with contributions from Observatoire de Meudon (France) financed by CNES and from DLR (Germany). The VIRTIS instrument industrial prime contractor was former Officine Galileo, now Leonardo Company, in Campi Bisenzio, Florence, Italy. Part of this research was supported by the ESA Express Procurement (EXPRO) RFP for IPL-PSS/JD/190.2016. D.K. acknowledges DFG-grant KA 3757/2-1. This work was supported by the International Space Science Institute (ISSI) through the ISSI International Team "Characterization of cometary activity of 67P/Churyumov-Gerasimenko comet". This research has made use of NASA’s Astrophysics Data System.

The COVID-19 pandemic has focused attention not only on health and social issues, but on the issue of digital transformation as well. Within a very short time, universities had to convert their courses to digital formats and university life was reduced to a minimum. To shed light on how the COVID-19 pandemic has affected universities, we investigated the following questions: How was this transformation accomplished? What advantages and disadvantages did it bring with it? How sustainable was this transformation? and What can the future of higher education look like? This study is based on the responses to two questionnaires for university staff and students conducted at the Chemnitz University of Technology between mid-July and September, 2020 (n = 369), and between February and March, 2021 (n = 252). Both questionnaires were analysed using descriptive statistics and qualitative content analysis. The results show wide variations in response to digital teaching and learning. Digital teaching and working/learning from home have brought both multiple benefits and multiple challenges at the same time. Working and learning from home was perceived as both enriching and overwhelming—even for the same individual. Respondents appreciated the flexibility associated with digital teaching, even though digital teaching was perceived as imposing excessive demands. This study reveals striking gaps in our knowledge and our actions linking digital transformation and sustainability and highlights how digital teaching can be further developed.

The COVID-19 pandemic has focused attention not only on health and social issues, but on the issue of digital transformation as well. Within a very short time, universities had to convert their courses to digital formats and university life was reduced to a minimum. To shed light on how the COVID-19 pandemic has affected universities, we investigated the following questions: How was this transformation accomplished? What advantages and disadvantages did it bring with it? How sustainable was this transformation? and What can the future of higher education look like? This study is based on the responses to two questionnaires for university staff and students conducted at the Chemnitz University of Technology between mid-July and September, 2020 (n = 369), and between February and March, 2021 (n = 252). Both questionnaires were analysed using descriptive statistics and qualitative content analysis. The results show wide variations in response to digital teaching and learning. Digital teaching and working/learning from home have brought both multiple benefits and multiple challenges at the same time. Working and learning from home was perceived as both enriching and overwhelming—even for the same individual. Respondents appreciated the flexibility associated with digital teaching, even though digital teaching was perceived as imposing excessive demands. This study reveals striking gaps in our knowledge and our actions linking digital transformation and sustainability and highlights how digital teaching can be further developed.

Venus is one of the less well studied planets in the inner solar system. Despite its mass being comparable to that of Earth, the development of its environmental conditions followed a completely different evolutionary path. Today's dense CO2 dominated atmosphere is characterized by extreme surface conditions of 92 bar and 735 K at the mean altitude of the planet's surface and a cloud layer enriched with sulfuric acid aerosols, which makes observations of the daytime surface in the visual spectral range impossible. This circumstance led to a long standstill for further space programs to Venus after the first space-based explorations of this planet in the 1970s through the mid-1990s, which was not broken until the launch of ESA's Venus Express (VEX) mission in 2005. Missions such as VEX, Akatsuki (JAXA), and BepiColombo (ESA; MERTIS, first Venus flyby) have made new VIS-IR spectroscopic measurements of Venus in recent years, contributing to the study of its atmosphere and surface. We report here selected results of these investigations and their comparison with earlier data. We derive from these discussion scientific and instrumental requirements for VIS-IR spectroscopic spaceborne measurements with focus to currently selected and future space missions such as EnVision (ESA) and VERITAS (NASA), and discuss their capabilities and limitations for atmospheric and surface studies.

The ESA-JAXA BepiColombo Mercury mission was launched in October 2018. It performed successful flybys of the Earth-Moon system on April 10, 2020 and of Venus on October 15, 2020 during which the MERTIS instrument operated. MERTIS obtained a total of 1.2 million spectra during the Moon flyby from a distance of more than 700000km. Venus observations started at a distance of more than 1.3 Mio km recording more than 3 million spectra. For reference at Mercury MERTIS will observe the planet from a distance of less than 1500km. These data and the Near-Earth commissioning show that MERTIS performance exceeds requirements.

Martian dust particles play an important part in radiative processes in Martian atmosphere, being involved in dust, H2O and CO2 cycles on Mars [1]. The most significant manifestations of such cycles are dust storms which last several weeks and strongly affect the thermal structure of Martian atmosphere [2]. In addition to regular storms, global dust storms (hereinafter GDS) occur irregularly once in several Martian Years (hereinafter MY) and cover the entire planet for months. GDS still remain unpredictable despite numerous studies [3]. The latest global dust storm occurred in MY 34 and has been simultaneously monitored by several spacecrafts including ExoMars Trace Gas Orbiter (TGO) [4]. In this paper we present results of analysis of thermal emission spectra of Mars measured with a Fourier-transform spectrometer ACS TIRVIM onboard TGO [5]. The main scientific goal of TIRVIM is long-term monitoring of temperatures and aerosols (dust and water ice) distribution in Martian atmosphere in nadir mode of observations in the 5–16 μm spectral range [6]. Here we consider two datasets obtained in MY 34: the first one covered the first month of the GDS in a period from 26th of May 2018 till 15th of July 2018 (Martian season Ls = 182.2°–211.7°), the second one lasted from 22nd of December 2018 till 18th of March 2019 (Ls = 310.9°–357.3°) and fully covered the regional dust storm (C-storm). Retrieval of temperatures, dust and ice content from the thermal emission of Martian atmosphere in 15 μm CO2 band has been done in a number of previous similar experiments [7, 8, 9]. We use iterative retrieval algorithm based on optimum estimation approach [10]. With TIRVIM spectral resolution Δν = 1.17 cm-1, temperature profiles may be retrieved from the surface to 55–60 km of altitude with the vertical resolution in the order of few kilometers in the lower atmosphere. Spectral range from 780 to 1300 cm-1 is free from CO2 absorption lines and is suitable for retrieving the temperature of Martian surface and column abundances of aerosols. Dust and water ice contents are defined as optical depths at wavelengths of local maxima of their spectral extinction cross sections [11]. We have obtained the thermal structures of Martian atmosphere at various local times during the first month of the global dust storm and during the whole regional storm. We have compared temperature fields in the nighttime and daytime at the peaks of the two observed storms with structure of the pure from dust atmosphere. Asymmetric heating with dust particles ejected into the atmosphere is clearly seen in Fig. 1. Diurnal contrasts of temperature between nighttime and daytime are represented in Fig. 2. We notice an excellent agreement with co-located MCS/MRO measurements [12], with the account for a worse vertical resolution of nadir sounding with TIRVIM. Along with the temperature field we also consider the variability of dust distribution during the two storms in MY 34. Spatial distributions of dust in terms of column optical depth at 1075 cm-1 at the peaks of the global dust storm and the regional dust storm are shown in Fig. 3. Due to unavoidable degeneracy of the dust and ice retrieval problems at some temperature conditions, these maps contain also unreliable high and zero values of optical depth, which are to be filtered out. Acknowledgements Science support in IKI is funded by the RSF grant #20-42-09035. References [1] Kahre M.A. et al. The Mars dust cycle. The atmosphere and climate of Mars. // MA: Cambridge Univ. Press, Cambridge, 2017 [2] Smith M.D. et al. 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Transdisciplinary learning is a response to address the comprehensive sustainability competencies for implementing the 17 sustainability goals of the Agenda 2030. Transdisciplinary contexts include socially distributed knowledge beyond scientific boundaries. This impacts the whole design process and specific tasks and roles of the researchers. Addressing the questions, "Which typical tensions, dilemmas and paradoxes need to be faced by researches in transdisciplinary settings?", and "How does the role of the researchers change and goes beyond traditional research settings when operating in transdisciplinary settings surrounded by tensions, dilemmas and paradoxes?", answers will be provided following existing analytical frameworks of transdisciplinary research design. Based on own experiences with and including observations of transdisciplinary settings at academia, transdisciplinary research and lecture settings will be analysed and compared by transdisciplinary criteria. Results show, in transdisciplinary settings, researchers or lecturers are more engaged with addressing poly‐contextuality, the consciousness of the innovation paradoxes and the side‐effects of ongoing interdependences. They take up multiple roles and have to deal with role ambiguity. Transdisciplinary lecture settings are even more demanding as they also have to meet the mentor role or maintain the students' learning progress.

The global textile industry typically is seen to have a negative image due to ethically questionable working and sourcing conditions in mainly Asian located low-cost production countries. The Rana Plaza building collapse in Dhaka, Bangladesh, on April 24, 2013, the DETOX campaign of Greenpeace, and the promotion of circular economy concepts by NGOs and scientists affected particularly companies such as H&M but not just exclusively. These aspects supported a change in corporate strategies toward more transparent communication and dissemination of statements and reports on corporate sustainability activities or strengthening commitment and involvement in multi-stakeholder initiatives to enhance social and environmental sustainability in sourcing and production countries. However, circular approaches focus mostly on economic and environmental sustainability, thereby neglecting the social dimension of sustainability and systemic change particularly necessary in the textile industry. In fact, limited understanding exists with regard to the following questions: Which topics and patterns concerning circular concepts and social sustainability or corporate responsibility have been considered in the global textile industry? In what way do academic viewpoints and corporate activities differ? We explore how discussions around circular approaches and business models for social sustainability in the textile industry have been evolving concurrently between 2008 and 2017 both in theory and in practice. The research employs a systematic software-based qualitative literature analysis in the context of the textile industry, thereby also exploring the illustrative practical example of the fast fashion retailer H&M. Our findings reveal that circular business models in the textile industry are becoming of increasing relevance, thus contributing to a sustainable development. However, particularly social aspects are underrepresented in scholarly publications on circular economy, yet promoted by textile companies. We conclude by highlighting implications and suggesting avenues for further research.

Introduction: The Venus Emissivity Mapper is the first flight instrument designed to focus on mapping the surface of Venus using several atmospheric windows around 1 µm. After years of development, VEM now has a mature design. An existing laboratory prototype has verified an achievable instrument SNR of well above 1000, as well as predicted error in retrieval of relative emissivity of better than 1%, assuming the availability of improved Venus topography.VEM science goals: The instrument will provide a global map of rock type from orbit, assessing iron contents and the redox state of the surface by observing the surface with six narrow band filters, ranging from 0.86 to 1.18 µm. Three additional windows allow corrections for cloud composition and variability, two measure water abundance, and three compensate for stray light. Continuous observation of Venus’ thermal emission will also place tighter constraints on current volcanic activity. Eight channels provide measurements of atmospheric water vapor abundance as well as cloud microphysics and dynamics, permitting accurate correction of atmospheric interference on the surface data.The instrument is currently part of two Phase A studies: is part of the payload of the NASA VERITAS mission as well as of the ESA EnVision mission, here as the VenSpec-M channel in the VenSpec spectrometer suite. Combining VEM with a high-resolution radar mapper will provide key insights into the divergent evolution of Venus and Earth. Flying VEM on more than one mission will enable a long timeline of monitoring for volcanic activity on Venus. Combined with the existing VenusExpress data, VEM enables detection and mapping of surface changes over decades.VEM Design: The VEM system design is a pushbroom multispectral imaging system. It leverages a proven measurement technique pioneered by VIRTIS on Venus Express (VEX). It also incorporates lessons learned from VIRTIS to achieve greatly improved sensitivity and spectral and spatial coverage:A filter array (rather than a grating) provides wavelength stability (band-center and width-scatter) ~5× more stable and maximizes signal to the focal-plane array (FPA). Spectral windows below 1µm are covered for the first time. A two-stage baffle decreases scattered light and improves sensitivity. Use of an InGaAs detector with an integrated thermal electric cooler (TEC) eliminates the need for cryogenic cooling. The design maturity, combined with a standard camera optical design, leads to low development risk.VEM prototyping: VEM has been under development for several years with significantly financial investment from DLR. Following creation of the first breadboard model in 2015 during Phase A for the NASA Discovery proposal VERITAS, a laboratory prototype (LP) of the VEM instrument has been developed. This prototype includes the development version of the VEM optics with a filter array with two active filter strips. The optics underwent a set of calibration measurements on sub-unit level at LATMOS prior to delivery to DLR. All key optical design parameters including transmission and wavelength coverage have been verified using the VEMO prototype.A first performance evaluation of the VEM prototype used two Venus analog samples heated to Venus surface temperatures. This was performed using the Venus simulations setup at the Planetary Spectroscopy Laboratory with the prototype mounted on the chamber. The retrieved emissivities match laboratory values, and uncertainty for a single unbinned exposure is VEM atmospheric correction: Methodology for retrieving surface emissivity is complex but well understood and demonstrated. To distinguish between surface and atmospheric contributions, VEM uses an updated version of the extensively tested pipeline developed to process VIRTIS data, combined with a radiative transfer model (RTM). Surface emissivity retrieval techniques were developed based on Galileo NIMS observations at 1700, 1800 and 2300 nm. VEM cloud bands occur at 1195, 1310, and 1510 nm, the first on the flank of the 1180‑nm surface windows. VEM’s cloud bands are close to surface bands, providing near-optimal correction. Only relative emissivity measurements are needed to calculate the spectral slope to meet our surface emissivity requirements. We do not have a requirement on the accuracy of the retrieved emissivity. However, we can now tie an emissivity retrieval to in situ measurements to assess accuracy. For this comparison, the Venera 9 and 10 landing sites (not observed by VIRTIS) will be observed by VEM both on EnVision and on VERITAS.VEM observes each spot on the surface multiple times. Therefore both atmospheric and instrument noise are reduced by averaging image swaths acquired at different times. Applying the updated analysis of atmospheric error for VEM parameters and taking multiple-look averaging into account, our capability for emissivity precision is better than 1.5% for all bands and better than 1% in most bands.Conclusion: VEM builds on recent advances in the laboratory analog spectroscopy at PSL at DLR. It is the first flight instrument designed to focus on mapping the surface of Venus using atmospheric windows around 1 µm. VEM has a mature design with an existing laboratory prototype that verifies an achievable instrument SNR of >1000, as well as a predicted error in the retrieval of relative emissivity of better than 1%.

ESA’s ExoMars program comprises two missions including the Trace Gas Orbiter (TGO), launched in 2016, and a rover and surface platform, to be launched in 2022. The main scientific objectives of the program are to investigate the Martian environment and climate and search for past or present signs of life. For this purpose, a suite of three infrared spectrometers for remote sensing (Atmospheric Chemistry Suite, ACS) is in use on TGO. One of these instruments is a Fourier transform spectrometer, TIRVIM (Thermal IR V-shape Interferometer Mounting in honor of Vassili Ivanovich Moroz), operating in nadir, limb or solar occultation mode between 1.7 and 17 μm. On ExoMars22’s surface platform the spectrometer FAST (Fourier for Atmospheric Species and Temperature) will study the atmosphere and surface at the landing site in the same wavelength range as TIRVIM on TGO. This paper presents the objectives of TIRVIM and FAST. It summarizes selected results of the determination of temperature profiles and dust content in the lower atmosphere of Mars based on radiative transfer modeling of TIRVIM data. Synergetic analyses of TIRVIM spectra and InSight (NASA) in situ measurements of temperature and pressure at InSight’s landing site in Elysium Planitia enable improvements of procedures to retrieve parameters from TIRVIM observations. First results on surface temperature obtained from these different data sets together with the measurements to be expected in the future from FAST offer a unique opportunity to compare in situ and IR remote sensing measurements.

The European Space Agency’s Rosetta mission1 has acquired unprecedented measurements of the surface of the nucleus of comet 67P/Churyumov–Gerasimenko (hereafter, 67P), the composition of which, as determined by in situ and remote-sensing instruments, including the VIRTIS instrument2, seems to be an assemblage of ices, minerals and organic material3. We performed a refined analysis of infrared observations of the nucleus of 67P carried out by the VIRTIS-M hyperspectral imager. We find that the overall shape of the infrared spectrum of 67P is similar to that of other carbon-rich outer Solar System objects, suggesting a possible genetic link with them. More importantly, we also confirm the complex spectral structure of the wide 2.8–3.6 µm absorption feature populated by fainter bands. Among these, we unambiguously identify the presence of aliphatic organics by their ubiquitous 3.38 µm, 3.42 µm and 3.47 µm bands. This infrared detection of aliphatic species on a cometary surface has strong implications for the evolutionary history of the primordial Solar System and is evidence that comets provide an evolutionary link between interstellar material and Solar System bodies4. A refined analysis of infrared observations of comet 67P/Churyumov–Gerasimenko from the VIRTIS instrument on board the Rosetta spacecraft has revealed the presence of aliphatic organic molecules on the comet nucleus.

This paper reports on the application of advanced hyperspectral analysis to support the non-destructive study of samples from long sediment cores (up to 280 m coring depth) collected under the Hominin Sites and Paleolake Drilling Program (HSPDP) in the Chew Bahir region of southern Ethiopia. For this purpose, the bidirectional reflectance of 35 core samples from different core depths in the wavelength range from 0.25 to 17 µm was measured. It can be directly compared with spectral remote sensing data of the corresponding land surface areas. We examined the relationship between the derived mineralogical and geochemical properties of the core samples to test for linkage to the hydroclimate history of the region. Using XRD and µXRD methods, it has been shown that an illitization of the smectites and an octahedral Al-to-Mg substitution occurs in the phyllosilicate materials present during phases that have been associated with increased salinity and alkalinity due to enhanced evaporation (Foerster et al., 2018). These processes are found to be accompanied by potassium fixation and they are associated with the increase of the layer charge due to the authigenic changes of the octahedral composition. Reflection spectroscopy is a suitable method for studying such mineralogical properties.We investigated the spectral properties over a wide spectral range from UV to MIR. This enables detection of absorption bands of crystal field transitions of transition metal ions in the UV/VIS range and to detect the characteristic bands of OH, H2O, M-OH lattice vibrations in the NIR. It also allows the study of the fundamental vibration bands as well as other typical MIR features like the Christiansen band or transparency features of silicates and thus helps to reconstruct weathering paths.The results show that the main mineralogical components are clays of the smectite group. The samples are rich in montmorillonite and show variable concentrations of calcite. The clays are composed of tetrahedral coordinated, corner-connected SiO4 for which Si is partially substituted by Al and of edge-linked Al (OH)6 octahedrons in which part of the Al is substituted by Mg and which are layered by OH and H2O groups. Thus all reflectance spectra show the characteristic absorption bands at 1.4 µm (OH), 1.9 µm (H2O), 2.2 µm (Al-OH), and 2.3 µm (Mg-OH). Their band depth ratios derived from continuum removed spectra have been used to characterize the clay structure within different climate periods. The results support the model of illitization and potassium fixation during dry climate intervals. In addition, the spectral indicators determined in the MIR can be used to specify the mineralogical properties of silicates and other materials in terms of their geochemical composition. In summary, the method is suitable for examining the main mineralogical components of Chew Bahir core samples and enables confirmation of climate-driven wet and dry weathering processes in the formation of phyllosilicates.Foerster, V. et al., (2018) Towards an understanding of climate proxy formation in the Chew Bahir basin, southern Ethiopian Rift. Palaeogeography, Palaeoclimatology, Palaeoecology, 501, 111-123.

The measured nitrogen-to-carbon ratio in comets is lower than for the Sun, a discrepancy which could be alleviated if there is an unknown reservoir of nitrogen in comets. The nucleus of comet 67P/Churyumov-Gerasimenko exhibits an unidentified broad spectral reflectance feature around 3.2 micrometers, which is ubiquitous across its surface. On the basis of laboratory experiments, we attribute this absorption band to ammonium salts mixed with dust on the surface. The depth of the band indicates that semivolatile ammonium salts are a substantial reservoir of nitrogen in the comet, potentially dominating over refractory organic matter and more volatile species. Similar absorption features appear in the spectra of some asteroids, implying a compositional link between asteroids, comets, and the parent interstellar cloud., Comment: Main manuscript and Supplementary material document, Accepted for publication in Science on February 14, 2020

Solar heating of a cometary surface provides the energy necessary to sustain gaseous activity, through which dust is removed1,2. In this dynamical environment, both the coma3,4 and the nucleus5,6 evolve during the orbit, changing their physical and compositional properties. The environment around an active nucleus is populated by dust grains with complex and variegated shapes7, lifted and diffused by gases freed from the sublimation of surface ices8,9. The visible colour of dust particles is highly variable: carbonaceous organic material-rich grains10 appear red while magnesium silicate-rich11,12 and water-ice-rich13,14 grains appear blue, with some dependence on grain size distribution, viewing geometry, activity level and comet family type. We know that local colour changes are associated with grain size variations, such as in the bluer jets made of submicrometre grains on comet Hale–Bopp15 or in the fragmented grains in the coma16 of C/1999 S4 (LINEAR). Apart from grain size, composition also influences the coma’s colour response, because transparent volatiles can introduce a substantial blueing in scattered light, as observed in the dust particles ejected after the collision of the Deep Impact probe with comet 9P/Tempel 117. Here we report observations of two opposite seasonal colour cycles in the coma and on the surface of comet 67P/Churyumov–Gerasimenko through its perihelion passage18. Spectral analysis indicates an enrichment of submicrometre grains made of organic material and amorphous carbon in the coma, causing reddening during the passage. At the same time, the progressive removal of dust from the nucleus causes the exposure of more pristine and bluish icy layers on the surface. Far from the Sun, we find that the abundance of water ice on the nucleus is reduced owing to redeposition of dust and dehydration of the surface layer while the coma becomes less red. Spectral analysis of the VIRTIS dataset shows two opposite seasonal colour cycles in the coma and on the surface of comet 67P/Churyumov–Gerasimenko, indicating an orbital water-ice cycle.

At present, sustainability science is mainly based on conscious information and strongly focused on analytical tools or strategies. Neuroscience has made obvious that human decisions are prepared by the unconsciousness. Intuition plays an important role in early and late stages of learning processes and has a crucial impact on decision-making. Thus, intuitive and unconscious thinking is crucial for management processes in general and production planning processes in the main. However, unconscious knowledge and human behaviour is predominantly neglected in production research. Especially the addressing of human machine interfaces (HMI), human cognitive biases have a crucial impact on decision making processes. Constellation work is based on unconscious knowledge and intuition. Thus, systemic structural constellations are an innovative tool to integrate unconscious knowledge in a research context. In systemic structural constellations specific foci of complex systems, such as a production system, can be simulated and represented through spatial arrangements of persons or symbols. So, the method was used to reveal relevant patterns of relationships, structures, interaction, implicit knowledge, including hidden or underlying dynamics and influences that are relevant to and within a production system to understand how the raised problems in HMI can be better solved. The guiding research question is: How can the use of structural systemic constellations improve decision-making processes in HMI contexts in production environments in order to increase sustainability? Results show sustainability seems to be a matter of consciousness and is closely linked to the bias group not enough meaning. Sustainability and complexity resemble more than being linked by trade-offs. The recognition of human biases can be trained to improve human-machine-interfaces and sustainability. Constellation work contributes to decision theory by supporting effectuation.

Sustainable innovations are inventions providing an essential progress concerning social, economic and ecological concerns. The emergence of Base of the Pyramid markets and the growing importance of the developing economies as new sources of frugal innovations has attracted the interest of scholars and practitioners. Frugal innovation is an inclusive approach to innovation that maximizes value for customers, shareholders, and society – while significantly reducing the use of financial and natural resources in developing countries. Reverse innovations are frugal products and services successful in developing markets that make their way back to industrialized countries by creating new market segments. Therefore, both concepts are crucial for facing sustainability challenges in developing countries and may also lend insights to business models in industrialized countries. As the relationship between frugal and reverse innovation and sustainability remains largely unexplored in the literature, this study aims to fill in this gap and answer the research question: How can frugal and reverse innovation strengthen sustainable development, and how can business models in this context be systemized and described? Employing a multiple case study design, a total of 59 frugal products and services were investigated from a business models and sustainability strategy perspective from June 2014 until June 2015. The direction of innovation was distinguished between (a) from developing countries to developing countries, (b) from industrialized countries to developing countries, (c) from industrialized countries to industrialized countries, and (d) from developing countries to industrialized countries with the purpose to find differences between different directions of innovation and economies. Findings show that entrepreneurs and companies offering frugal and reverse products and services manage to combine the business model elements in an insightful manner and create economic, social and environmental value.

Base- oder Bottom of the Pyramid-Markte als Quelle und Abnehmer frugaler Innovationen stellen eine Herausforderung im Rahmen einer nachhaltigen Entwicklung und inklusiver Wertschopfung dar. Beispielhaft an zwei frugalen Innovationen werden wesentliche Charakteristika eines Nachhaltigkeitsmanagements aufgezeigt. Eine kollaborative Wertschopfungskette mit vielfaltigen Partnern fuhrt zum Erfolg. Lokale Beschaffungsaktivitaten fuhren zu erheblichen Nachhaltigkeitsvorteilen.

Thermal cooling rates QC and solar heating rates QH in the atmosphere of Venus at altitudes between 0 and 100 km are investigated using the radiative transfer and radiative balance simulation techniques described by Haus et al. (2015b, 2016). QC strongly responds to temperature profile and cloud parameter changes, while QH is less sensitive to these parameters. The latter mainly depends on solar insolation conditions and the unknown UV absorber distribution. A parameterization approach is developed that permits a fast and reliable calculation of temperature change rates Q for different atmospheric model parameters and that can be applied in General Circulation Models to investigate atmospheric dynamics. A separation of temperature, cloud parameter, and unknown UV absorber influences is performed. The temperature response parameterization relies on a specific altitude and latitude-dependent cloud model. It is based on an algorithm that characterizes Q responses to a broad range of temperature perturbations at each level of the atmosphere using the Venus International Reference Atmosphere (VIRA) as basis temperature model. The cloud response parameterization considers different temperature conditions and a range of individual cloud mode factors that additionally change cloud optical depths as determined by the initial latitude-dependent model. A QH response parameterization for abundance changes of the unknown UV absorber is also included. Deviations between accurate calculation and parameterization results are in the order of a few tenths of K/day at altitudes below 90 km. The parameterization approach is used to investigate atmospheric radiative equilibrium (RE) conditions. Polar mesospheric RE temperatures above the cloud top are up to 70 K lower and equatorial temperatures up to 10 K higher than observed values. This radiative forcing field is balanced by dynamical processes that maintain the observed thermal structure.

After coming to rest on the night side of comet 67P/Churyumov-Gerasimenko, the ROLIS camera on-board Rosetta’s Philae lander acquired five images of the surface below the lander, four of which were with the aid of LED illumination of different colors. The images confirm that Philae was perched on a sloped surface. A local horizon is visible in one corner of the image, beyond which we can see the coma. Having spent a full day on the surface Philae was commanded to lift and rotate, after which a final, sixth, LED image was acquired. The change in perspective allowed us to construct a shape model of the surface. The distance to the foreground was about 80 cm, much larger than the nominal 30 cm. This caused stray light, rather than directly reflected LED light, to dominate the image signal, complicating the analysis. The images show a lumpy surface with a roughness of apparently fractal nature. Its appearance is completely different from that of the first landing site, which was characterized by centimeter to meter-sized debris (Mottola et al., 2015). We recognize neither particles nor pores at the image resolution of 0.8 mm per pixel and large color variations are absent. The surface has a bi-modal brightness distribution that can be interpreted in terms of the degree of consolidation, a hypothesis that we support with experimental evidence. We propose the surface below the lander to consist of smooth, cracked plates with unconsolidated edges, similar to terrain seen in CIVA images.