ESA Research Research Articles

Introduction

In September 2016, we organized a roundtable entitled “Community engaged cultural research: an emerging agenda of practice” at the 9th Midterm Conference of the ESA Research Network Sociology of the Arts in Porto, Portugal. The authors sharing their research during that session challenged us to go further and publish our experiences with society-friendly research in a variety of cultural contexts, practices, backgrounds and beliefs. By choosing the theme of “community and creative research”, this thematic issue of Conjunctions has gathered experiences from around the world (Australia, Brazil, Denmark, Finland, Portugal, Switzerland, Argentina and Cyprus) on different approaches to democratic practice using the lens of cultural participation. It feeds on the intersection of action research work performed by academics, activists, artist, theorists and citizens, who study and work within different sectors of our societies through participatory methodologies.

History of ESA's Historical Records Committee

History of ESA's Historical Records Committee

L’effet de l’âge, du genre et du statut socioéconomique sur l’utilisation des services de médecine générale pour des symptômes de détresse psychologique

The objective of this study was, first, to document the psychometric characteristics of a measure of the older adults' socioeconomic status and, secondly, to test the effect of the socioeconomic status on the association between the older adults perceived need to improve their mental health and their use of services in the general medical sector for psychological distress symptoms taking into account the effect of age and gender. Data used in this study come from the ESA study (Enquête sur la santé des ainés) on mental health and aging, conducted in 2005-2008 using a probabilistic sample (n=2811) of the older adult population aged 65 years and over living at home in Quebec. Our results showed that a measurement model of the older adults' socioeconomic status including an individual-level (SES_I) and an area/contextual-level dimension of socioeconomic deprivation (SES_C) was plausible. The reliability of the SES index used in the ESA research program was .92. Our results showed that women (b=-.43) and older people (b=-.16) were more at risk to have a disadvantaged socioeconomic status. However, our results did not show evidence of a significant association between the older adults' socioeconomic status, their perception of a need to improve their mental health and the use of medical services for psychological distress symptoms in the general medical sector in the older adult population in Quebec. Our results do not support the idea suggested in other studies that socioeconomic status has an effect on the older adults use of services for psychological distress symptoms in the general medical sector and suggest that in a context where medical health services are provided under a public insurance programme context, the socioeconomic status does not influence access to services in the general medical sector in the older adult population.

Comparison of Column-Averaged Volume Mixing Ratios of Carbon Dioxide Retrieved From IASI/METOP-A Using KLIMA Algorithm and TANSO-FTS/GOSAT Level 2 Products

The ESA research project “Application of KLIMA Algorithm to CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Retrieval from IASI/METOP-A Observations and Comparison with TANSO-FTS/GOSAT Products” aims to develop a dedicated software, based on the KLIMA inversion algorithm (originally proposed by IFAC-CNR for the 6 ° cycle of ESA Earth Explorer Core Missions), suited for CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> retrieval and integrated into the ESA grid-based operational environment Grid Processing On-Demand (G-POD) to process Level 1 data acquired by the infrared atmospheric sounding interferometer (IASI) and to perform a comparison with Thermal And Near-infrared Sensor for carbon Observation Fourier Transform Spectrometer (TANSO-FTS), on board of the Greenhouse gases Observing SATellite (GOSAT), Level 2 data. In order to obtain a reasonable capacity to bulk processing IASI data, we choose to integrate the KLIMA code into the G-POD system. For this reason, we investigated an optimized version of the KLIMA algorithm, aiming at developing a nonoperational retrieval code with adequate features for the integration on the G-POD system. The optimized version of KLIMA retrieval code has been completed and integrated on the G-POD operational environment and is available for bulk processing of IASI data. Using the KLIMA inversion code integrated into the ESA G-POD, it was possible to perform an extensive comparison of a selected set of IASI measurements collocated with TANSO-FTS observations. We performed an extensive comparison of the column-average CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> dry air mole fraction (XCO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) retrieved from IASI measurements by using the KLIMA/G-POD inversion code with the operational Level 2 SWIR products (Version 01.xx and Version 02.xx) from collocated TANSO-FTS observations. In this work, we describe the strategy adopted for the comparison and we show the results of this activity.

ESA research and development activity on SSA-NEO preliminary definition

The paper gives an account of goals, prospects, and planning of the first ESA research associated with definition of the SSA-NEO segment and puts it in the context of ESA system engineering practices of ESA (as defined in ESA’s ECSS standards).

Very high delta-V missions to the edge of the solar system and beyond enabled by the dual-stage 4-grid ion thruster concept

A new and innovative type of gridded ion thruster, the “Dual-Stage 4-Grid” or DS4G concept, has been proposed and its predicted high performance validated under an ESA research, development and test programme. The DS4G concept is able to operate at very high specific impulse and thrust density values well in excess of conventional 3-grid ion thrusters at the expense of a higher power-to-thrust ratio. This makes it a possible candidate for ambitious missions requiring very high delta-V capability and high power. Such missions include 100 kW-level multi-ton probes based on nuclear and solar electric propulsion (SEP) to distant Kuiper Belt Object and inner Oort cloud objects, and to the Local Interstellar medium. In this paper, the DS4G concept is introduced and its application to this mission class is investigated. Benefits of using the DS4G over conventional thrusters include reduced transfer time and increased payload mass, if suitably advanced lightweight power system technologies are developed. A mission-level optimisation is performed (launch, spacecraft system design and low-thrust trajectory combined) in order to find design solutions with minimum transfer time, maximum scientific payload mass, and to explore the influence of power system specific mass. It is found that the DS4G enables an 8-ton spacecraft with a payload mass of 400 kg, equipped with a 65 kW nuclear reactor with specific mass 25 kg/kW (e.g. Topaz-type with Brayton cycle conversion) to reach 200 AU in 23 years after an Earth escape launch by Ariane 5. In this scenario, the optimum specific impulse for the mission is over 10,000 s, which is well within the capabilities of a single 65 kW DS4G thruster. It is also found that an interstellar probe mission to 200 AU could be accomplished in 25 years using a “medium-term” SEP system with a lightweight 155 kW solar array (2 kg/kW specific mass) and thruster PPU (3.7 kg/kW) and an Earth escape launch on Ariane 5. In this case, the optimum specific impulse is lower at 3500 s which is well within conventional gridded ion thruster capability.

Microstructures Observed during Directional Solidification along the Univariant Eutectic Reaction in a Ternary Al-Cu-Si Alloy

Within the frame of the ESA research program SETA, “Solidification along a Eutectic Path in Ternary Alloys”, experiments have been performed focussing on several distinct subtopics. One of these subtopics is to study coupled growth along the univariant eutectic reaction: L → α + β. In this paper, the influence of the growth velocity v on the morphology of the solid/liquid interface is evaluated in a ternary Al-Cu-Si alloy with a composition close to the univariant eutectic groove L → α(Al) + θ-Αl2Cu. Different structural regions can be identified in terms of the stability of the solid-liquid interface (morphological stability) and the stability of the coupling (competitive growth) during unidirectional solidification as function of the solidification parameters. It is found that two-phase planar growth with a lamellar arrangement can be obtained at a sufficiently low growth rate v. The measured interlamellar spacing follows the Jackson and Hunt relationship λ2v = constant. At a higher growth velocity first a destabilisation of the solid/liquid interface is observed and finally competitive growth is observed revealing primary θ-Al2Cu growing ahead of the eutectic interface. It is assumed that the cellular break-up is a two-step process related to the crystallography of the system. Fitting the different morphologies into one microstructure map, an extension of the coupled zone concept as has been proposed for binary alloys is necessary.

Metallurgy in Space

Over the past five years, an application-oriented research strategy has been initiated by ESA to permit valuable microgravity research in a broad range of physical sciences. The main objective is to integrate ESA, national activities and industry into an overall European strategy, which will allow research to be performed aboard the International Space Station (ISS), as well as other microgravity platforms, like unmanned space capsules, sounding rockets and parabolic flights. A key area of microgravity research is centred on metallurgy in space. The principal aims of this research field are (i) to investigate various physical phenomena during solidification processes and (ii) to determine the thermophysical properties of important liquid alloys. A number of metallurgical sub-topics have been identified in the ESA research programme, including the columnar-to-equiaxed transition during solidification; metastable and non-equilibrium solidification; multiphase multicomponent alloy solidification; eutectic, peritectic, monotectic and intermetallic alloy growth; fluid flow effects on mushy zone formation; and the measurement of thermophysical properties of liquid alloys. This review paper will therefore highlight the theoretical, experimental and modelling efforts currently being undertaken in the ESA programme.

Univariant Eutetic growth in ternary Al-Cu-Ag-alloys

Within the frame of the joint ESA research program “SETA” (Solidification along a Eutectic path in Ternary Alloys) univariant solidification is investigated in preparation of experiments onboard the ISS. The ternary eutectic alloys under examination belong to the ternary system Al-Cu-Ag. The focus is on coupled eutectic growth of two solid phases along the univariant eutectic groove (marked (1) in fig. 1 and 2) that extends from the binary Al-Cu eutectic towards the ternary nonvariant eutectic with increasing Ag content. This presentation reports on three different approaches to the topic: by means of thermodynamics, experiments and microstructure simulations and their interaction. Experiments and simulations are compared regarding planar and cellular microstructure formation and phase compositions. Thermodynamic data and calculations serve as interpretational link between experiment and simulation and as main input to the simulations.

ESA's new intellectual property policy

This paper outlines the new intellectual property policy for ESA research and development contracts and how the new general contract provisions achieve a balance between the interests of the individual contractor, the member states and ESA's need to improve the competitive position of European industry as a whole.

A SURVEY OF STABILITY OF FUZZY LOGIC CONTROL WITH AEROSPACE APPLICATIONS

During recent years considerable efforts have been devoted to guarantee the stability of fuzzy logic control (FLC). Several stability analysis methods have been established, and stable control designs have been introduced. This is important to pave the way for the use of FLC in applications were no risks should be run. Aerospace is a clear example of a field where control must be sure. This paper is motivated by an ESA research project on stability of FLC concerning, in particular, aerospace potential applications. The paper present a review of the research on FLC stability, both in time and frequency domains, including also several alternatives of stable control design methods. In addition, there is a section about FLC applications in aerospace.

Advancements in vibroacoustic evaluation of satellite structures

The importance of the launcher vibroacoustic environment is increasing with respect to satellite loads due to the increase in size and decrease in surface mass of lightweight appendages like antennas and solar arrays. The loads generated by the vibroacoustic environment need to be covered adequately to ensure satellite structural integrity. This is of particular importance in the low-frequency range where the low frequencies of light appendages and equipment couple with the acoustic environment. In order to cope with the increasing demand for prediction of structural loads due to the acoustic environment, various methods have been developed in the frame of ESA research and development activities. These range from simplified approaches with partial fluid–structure coupling, e.g. the POSTAR package provided by INTESPACE (France) to more sophisticated approaches with full fluid–structure coupling. In the frequency domain this includes pure finite element modelling techniques, where specific tools have been developed by FFA (Sweden) using the ASKA package, as well as coupled finite element—boundary element approaches that have been developed in cooperation with DASA–Dornier (Germany), STRACO (France) and FFA using the commercial packages ASKA and RAYON. For fully coupled fluid structure analysis in the time domain the ASTRYD code from METRAVIB (France) is employed where advancements have been supported by CNES. Applications of these tools range from simple benchmarks such as simply supported plates, cavity enclosures or generic satellite-fairing models to complex satellite structure configurations. Evaluations of antenna reflector structures (Artemis communication antenna) and satellite equipment panels (polar platform) are presented. The paper covers also the investigation of payload/fairing effects (influence of fairing helium purging on the coupled-system response) together with DASA–Dornier, FFA and STRACO, as well as the vibroacoustic analysis of solar array stacks carried out by FOKKER (The Netherlands) and METRAVIB, where the air effects in the inter panel gaps are being taken into account.

Esa Microgravity Research Activities In The Field Of Physical Sciences And Applications

During the eighties, microgravity research focussed predominantly on the investigation of fundamental phenomena, often with limited industrial support. Although this approach led to some rather impressive breakthroughs in terms of new theoretical insights and microgravity experimentation, the need for increased co-ordination and interest from industry became increasingly apparent. In this decade, a user-driven research strategy has been instigated by ESA to promote microgravity research. The objective is to coordinate ESA, national activities and industry into an overall European strategy, which will allow valuable application-oriented microgravity research to be performed aboard the International Space Station (ISS). On this basis, it is expected that scientific progress will evolve even more rapidly due to the easier planning, regular access and longer experiment-durations associated with the ISS. This paper highlights the wealth of microgravity research being co-ordinated by ESA in the field of physical sciences. A number of key areas of research under microgravity conditions are currently being explored such as alloy solidification, crystal growth,measurement of thermophysical properties, combustion mechanisms, fluid flow, cold atom physics and complex plasmas, to name but a few. The following sections will provide background information relating to the various ESA research programmes, as well as emphasising their microgravity relevance.

Development of technologies for production of high quality grazing incidence x-ray mirrors on graphite epoxy substrates

The design concept of the mirrors for the European Space Agency's high throughput x-ray spectroscopy mission XMM is characterized by thin (1 mm) graphite epoxy shells as the mirror structure and a replication technique to produce the mirror surface. The mirror microroughness is specified to r 0.5 nm (rms); profile errors should not exceed 2.5 arcsec. An ESA research study has been performed by Carl Zeiss and subcontractors (Dornier GmbH, Max Planck Institut für Extraterrestrische Physik/Garching, University of Leicester, X-ray Astronomical Group, Dept. of Physics) to clarify whether graphite epoxy mirror structures are able to meet the tight XMM mirror figuring and surface requirements and to determine what measures have to be taken to overcome the typical problems associated with composite materials used as mirror substrates, such as print-through of fibers and inner structure, short term/long term stability, and water absorption and outgassing. The starting conditions and progress during development are described. The present status of optical and x-ray performance of replicated flat graphite epoxy mirrors is reported, and aspects for further improvement of graphite epoxy mirrors is discussed.

NASA's plans to observe the Earth's atmosphere with lidar

The requirements for lidar observations of the Earth's atmosphere and the characteristics of the systems to provide these observations are discussed. The planned Earth Observing System (Eos) will offer platforms with adequate mass and power capabilities from which to make these lidar observations. Planned Eos lidar applications include the laser atmospheric wind sounder (LAWS), and the global backscatter experiment planned for it; the lidar atmospheric sounder and altimeter (LASA); and the ESA research facility instrument ATLID (atmospheric lidar). The laser requirements of all of the Eos laser instruments are presented. >