Space Instruments Research Articles

Miniature 4-Element MIMO Antenna System Designed From Transparent Glass Substrate and Aluminum Foil Radiator

The use of transparent antennas has been gaining popularity in recent years. Today many types and designs of display apparatus can be seen along city streets and for buildings as a backup power supply. Transparent antennas can be used for cladding the modern glass buildings. Transparent antennas also can be placed directly on top of solar cells and resolve the issue of competing for limited surface real estate. Like integration with the solar panels of small satellites, where limited surface area is an issue for mounting antennas, solar cells, and space instruments. This paper discuss the methods and materials used to design a transparent antennas that can be integrated with solar cells to solve the issue of competing for limited surface real estate and backup the short of electricity in the sunny country Sudan. In this paper a proposed a 4-element meander line MIMO Multiple Inputs Multiple Outputs antenna system designed from Aluminum foil radiator over transparent glass substrate this design is transparent partially. Despite of the unfamiliar materials used for the antenna design and it is a limited size MIMO system the simulated and measured results showed XBand matched bandwidth. In this work the antenna is designed and the solar cell module has been proposed theoretically.

Modeling infrared behavior of multilayer diffractive optical elements using Fourier optics.

In this paper, we propose to explore the infrared (IR) behavior of multilayer diffractive optical elements (MLDOEs). IR MLDOEs are designed for the development of space instruments dedicated to Earth observation. The phase effect of the MLDOE on a paraxial plane wave is studied using exact kinoform shapes for each layer. The modeling of the optical path difference uses thin element approximation. Until now, MLDOEs have been designed and simulated on ray-tracing software with binary diffractive layers. In this study, after passing through the MLDOE, the field is propagated using a method that utilizes the angular spectrum of plane waves. The Strehl ratio is used to determine the "best focus" plane, where it is shown that the focalization efficiency is above 95% for the working order in the mid- and long-wave IR bands. This result, along with the very low energy content of the other orders, proves the strong imaging potential of MLDOEs for dual-band applications. It is also demonstrated that the MLDOE has the same chromatic behavior as standard DOEs, making it a very useful component for IR achromatization.

Identifying key parameters for predicting materials with low defect generation efficiency by machine learning

The primary radiation damage is an important part of the radiation process, which is of current interest as the rapid development of nuclear reactors and space instrumentation. In this study, using machine learning, we have demonstrated that atomic mass difference, Poisson’s ratio, mean atomic mass, and mass density have significant influence on the defect generation efficiency of a material during the primary damage step. Furthermore, we construct a new dataset by using these important features and obtain a well-trained neural network for predicting new materials with low efficiency of defect generation. In our study, the target of the dataset for training the predictor is constructed using the results from molecular dynamics simulations. This work provides the guiding information for designing materials with low efficiency of defect generation.

Inventory classification system in space mission component replenishment using multi-attribute fuzzy ABC classification

PurposeThis project attempts to present a space component inventory classification system for space inventory replenishment and management. The authors propose to adopt a classification system that can incorporate all the different variables in a multi-criteria configuration. Fuzzy logic is applied as an effective way for formulating classification problems in space inventory replenishment.Design/methodology/approachA fuzzy-based approach with ABC classification is proposed to incorporate all the different variables in a multi-criteria configuration. Fuzzy logic is applied as an effective way for formulating classification problems in space inventory replenishment of the soil preparation system (SOPSYS) which is used in grinding and sifting Phobos rocks to sub-millimeter size in the Phobos-Grunt space mission. An information system was developed using the existing platform and was used to support the key aspects in performing inventory classification and purchasing optimization.FindingsThe proposed classification system was found to be able to classify the inventory and optimize the purchasing decision efficiency. Based on the information provided from the system, implementation plans for the SOPSYS project and related space projects can be proposed.Research limitations/implicationsThe paper addresses one of the main difficulties in handling qualitative or quantitative classification criteria. The model can be implemented using mathematical calculation tools and integrated into the existing inventory management system. The proposed model has important implications in optimizing the purchasing decisions to shorten the research and development of other space instruments in space missions.Originality/valueInventory management in the manufacture of space instruments is one of the major problems due to the complexity of the manufacturing process and the large variety of items. The classification system can optimize purchasing decision-making in the inventory management process. It is also designed to be flexible and can be implemented for the manufacture of other space mission instruments.

On Fault Diagnosis for High-G Accelerometers via Data-Driven Models

Shock test is a pivotal stage for designing and manufacturing space instruments. As the essential components in shock test systems to measure shock signals accurately, high-g accelerometers are usually exposed to hazardous shock environment and could be subjected to various damages. Owing to that these damages to the accelerometers could result in erroneous measurements which would further lead to shock test failures, accurately diagnosing the fault type of each high-g accelerometer can be vital to ensure the reliability of the shock test experiments. Additionally, in practice, an accelerometer in one malfunction form usually outputs mutable signal waveforms, so that it is difficult to empirically judge the fault type of the accelerometer based on the erroneous readings. Moreover, traditional hardware diagnosis approaches require disassembling the sensor’s package shell and manually observing the damage of the elements inner the sensor, which are less-efficient and uneconomical. Aiming at these problems, several data-driven approaches are incorporated to diagnose the fault types of high-g accelerometers in this work. Firstly, several high-g accelerometers with most frequent types of damage are collected, and a shock signal dataset is gathered by conducting shock tests on these faulty accelerometers. Then, the obtained dataset is used to train several base classifiers to identify the fault types in a supervised fashion. Lastly, a hybrid ensemble learning model is established by integrating these base classifiers with both heterogeneous and homogeneous models. Experimental results show that these data-driven methods can accurately identify the fault types of high-g accelerometers from their mutable erroneous readings.

Proton Aurora and Optical Emissions in the Subauroral Region

Optical structures located equatorward of the main auroral oval often exhibit different morphologies and dynamics than structures at higher latitudes. In some cases, questions arise regarding the formation mechanisms of these photon-emitting phenomena. New developments in space and ground-based instruments have enabled us to acquire a clearer view of the processes playing a role in the formation of subauroral structures. In addition, the discovery of new optical structures helps us improve our understanding of the latitudinal and altitudinal coupling that takes place in the subauroral region. However, several questions remain unanswered, requiring the development of new instruments and analysis techniques. We discuss optical phenomena in the subauroral region, summarize observational results, present conclusions about their origin, and pose a number of open questions that warrant further investigation of proton aurora, detached subauroral arcs and spots, stable auroral red (SAR) arcs, and STEVE (Strong Thermal Emission Velocity Enhancement).

Budżet obywatelski jako mechanizm społecznego wytwarzania przestrzeni miejskiej

Od wprowadzenia pierwszego budżetu obywatelskiego w Polsce mija właśnie dekada. Przez ten czas mechanizm polegający na włączaniu mieszkańców w proces współdecydowania o pewnej puli środków publicznych upowszechnił się w znacznej części polskich miast i miasteczek. Co więcej, zaczęto wprowadzać wojewódzkie, szkolne, wydziałowe i zielone warianty budżetów obywatelskich. Powszechność nie jest jednak gwarantem jakości. Polskie budżety obywatelskie obarczone są pewną, dość istotną, wadą, a mianowicie w zdecydowanej większości pozbawione są komponentu dyskusji, co sprawia, że w jakimś sensie stają się tylko pozornym narzędziem partycypacji. Niemniej jednak, mimo powyższej wady oraz stosunkowo niskich środków finansowych, stały się one dość skutecznym instrumentem kształtowania przestrzeni. Ze względu na wspomniane mankamenty w artykule używam określenia „quasi-partycypacyjne wytwarzanie przestrzeni”. W artykule prezentuję dane dotyczące rezultatów tego społecznego wytwarzania przestrzeni w odniesieniu do czterech wybranych miast. Analizie poddaję pięć pierwszych edycji budżetu obywatelskiego zrealizowanych w tych miastach.

Seasonal changes of Sahara desert dust transport over Balkans

This article presents an investigation of seasonal behavior of Sahara desert dust transport over the Balkans. The data used is satellite measurements of monthly averaged Absorption Aerosol Index (AAI) value. The researched period is from June 1995 till the end of 2019. The data used is from four different space instruments onboard five satellites. The area of interest is a rectangle with corners 23 E 43 N and 24 E 35 N. The data from different sources is compared and discussed.

Assessment of NO2 Pollution Level during the COVID-19 Lockdown in a Romanian City

This study investigates changes in pollution associated with the lockdown period caused by the COVID-19 pandemic in Galati (45.43° N, 28.03° E), a Romanian city located in the southeast of Romania. The study is focused on nitrogen dioxide (NO2), a trace gas which can be related to emissions from industrial activities, heating, and transportation. The investigation is based on in situ observations from local Air Quality Monitoring Stations (AQMS) and mobile remote sensing observations by Differential Optical Absorption Spectroscopy (DOAS) technique. We also show results of the NO2 vertical column measured by TROPOMI (TROPOspheric Monitoring Instrument), a space instrument onboard of satellite mission Sentinel-5P, to complement local ground-based measurements. For in situ observations, the lockdown interval (23 March 2020–15 May 2020) was separated from normal periods. The decrease in local NO2 concentration during lockdown, measured in situ, is rather small, of about 10–40% at the most, is observed only at some stations, and is better seen during workdays than during weekends. We conclude that the decrease in NO2 content over Galati city during lockdown is relatively small and may be attributed to the reduction in local traffic, a consequence of special measures and restrictions imposed during the COVID-19 lockdown by the Romanian authorities.

A New Way of Automated Dust Control of the External Atmosphere of a Spacecraft During Thermal-Vacuum Testing

During ground-based thermal vacuum tests of spacecraft, it is necessary to control and monitor the change in dust content in closed and semiclosed hollows of the spacecraft, near the optical surfaces of scientific and service hardware, mirrors, solar arrays, multilayer insulation, as well as in the volume of the thermal-vacuum chamber itself during its evacuation etc. It is known that the scientific reliability and significance of the results from instruments in space to ground-based research centers are greatly affected by dusty optics. The article provides a description of a new method for automated dust control of the external atmosphere of a spacecraft and its modules during thermal vacuum tests. A patent has been issued for this method; the patent holder is the Russian Federation, on behalf of which the State Space Corporation Roscosmos acts (RU). In addition to the rocket and space and aviation industries, this method can be used in electronic and microelectronic technology, nuclear technology, medicine, the food industry, etc.

RAYMOND MICHARD AND HIS SOLAR PHYSICS GROUP AT PARIS-MEUDON OBSERVATORY

During the second half of the twentieth century, an important Solar Research Department was developed in the Paris-Meudon Observatory thanks to Raymond Michard. After several years devoted to theoretical studies about stellar atmospheres at the Institut d'Astrophysique de Paris Michard joined the Paris- Meudon Observatory in 1954. He replaced Lucien d'Azambuja as Director of the Solar Section, and succeeded to attract new young scientists, while building new high-performance instruments in good sites such as Pic du Midi. He became Director of the Solar and Planetary Department in 1968. All topics of solar physics were investigated, providing many results about coronal physics, solar activity and flares, but also fine structures of the quiet Sun. Michard knew that the best research involved successful collaborations. Eclipse missions, international cooperation and access to space instruments were developed. Participation to the European JOSO association prepared the future THEMIS telescope. In 1971 Michard left the Solar Department to be successively the President of Paris Observatory and then Nice Observatory. But his Solar Physics group in Meudon went on working with topics and means that he had successfully initiated.

Spatial coherence characterization of light: An experimental study using digital micromirror devices

We present spatial coherence measurements of partially coherent light in the far-field of incoherent sources with an experimental setup based on the Thompson–Wolf and Partanen–Turunen–Tervo experiments, to be performed in the context of a possible solar coherence measurement space instrument. The optical setup consists of a telescope to collimate light from a source, to diffract it by a digital micromirror device implementing a Young double-aperture interferometer in retroreflection mode, and finally to image the source into a two-dimensional sensor. Two multimode optical fibers with different diameters were used as incoherent sources and the results obtained for the spectral degree of coherence are compared to those expected from the van Cittert–Zernike theorem.

Development of a compact water activity sensor system for planetary exploration

Water is a fundamental requirement for life. Its biological availability is partly determined by water activity and thus measuring this parameter is vital in industries such as food, agriculture and beyond. Apart from its terrestrial applications, water activity is also important in planetary exploration, for example in determining habitability in the subsurface of Mars, icy moons and other regions of interest in the Solar System. This paper reports a miniaturized water activity sensor for measurement in planetary environments. In line with space instrumentation constraints, objectives included minimizing the weight and dimensions of the sensor system, lowering the power consumption, enabling smaller sample volumes and achieving faster measurement time. We describe the design, construction, testing and field validation of this instrument.

Magnetically coupled atmosphere, fast sausage MHD waves, and forced magnetic field reconnection during the SOL2014-09-10T17:45 flare

Aims.We study the physical properties and behaviour of the solar atmosphere during the GOES X1.6 solar flare on 2014 September 10.Methods.The steady plasma flows and the fast sausage MHD waves were analysed with the wavelet separation method. The magnetically coupled atmosphere and the forced magnetic field reconnection were studied with the help of the Vertical-Current Approximation Non-linear Force-Free Field code.Results.We studied a mechanism of MHD wave transfer from the photosphere without dissipation or reflection before reaching the corona and a mechanism of the wave energy distribution over the solar corona. We report a common behaviour of (extreme)ultraviolet steady plasma flows (speed of 15.3 → 10.9 km s−1) and fast sausage MHD waves (Alfvén speed of 13.7 → 10.3 km s−1and characteristic periods of 1587 → 1607 s), propagating in cylindrical plasma waveguides of the individual atmospheric layers (photosphere → corona) observed by SDO/AIA/HMI and IRIS space instruments. A magnetically coupled solar atmosphere by a magnetic field flux tube above a sunspot umbra and a magnetic field reconnection forced by the waves were analysed. The solar seismology with trapped, leakage, and tunnelled modes of the waves, dissipating especially in the solar corona, is discussed with respect to its possible contribution to the outer atmosphere heating.Conclusions.We demonstrate that a dispersive nature of fast sausage MHD waves, which can easily generate the leaky and other modes propagating outside of their waveguide, and magnetic field flux tubes connecting the individual atmospheric layers can distribute the magnetic field energy across the active region. This mechanism can contribute to the coronal energy balance and to our knowledge on how the coronal heating is maintained.

Black Holes and the Supermassive Compact Object at the Galactic Center: Multi-arts of Thought and Nature

Black Holes and the Supermassive Compact Object at the Galactic Center: Multi-arts of Thought and Nature

Isolation of Teeth in Children: A Review

Isolation is done for proper control of moisture, good accessibility and visibility, to provide adequate spacefor instrumentation and operation. Most of the children are non-cooperative during treatment. So, isolation ismandatorily necessary for pediatric patients. Studies have shown that there are successful retention rates ofadhesive restoration when a rubber dam is used rather than any other isolation technique. The judicious useof rubber dam ensures greater patient comfort and delivery of high-quality dental care to pediatric patients.

Detecting sulfur on the Moon: The potential of vacuum ultraviolet laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) receives increasing interest in the field of space exploration. Some volatile elements important to planetary research are, however, challenging to detect with conventional LIBS because their strongest emission lines lie in the vacuum-UV (VUV) spectral range below 200nm. We demonstrate the potential of LIBS detection in the VUV range from 125 to 190nm on one of the relevant challenging elements, sulfur (S), in a lunar context. With our laboratory set-up, we detected S in lunar analogues at concentrations ranging from 0.5 to 4.0at% in a time-integrated configuration. The experiments were conducted in high vacuum (10−3 Pa) with laser parameters realistic for a space instrument (1064nm, 25mJ, 6ns). The results indicate improved detection capabilities for S in a lunar geological context as compared to LIBS in the more common UV/VIS/NIR spectral range. We found limits of detection in the order of 0.5at% S for all investigated sample series. Normalization by total intensity and by an internal standard, in our case by the emission signal of the O I triplet at 130nm, was tested as well, but did not yield a noticeable improvement for our data. Besides S, we were also able to detect Al, Fe, O, Si and Ti from the lunar analogue matrix.

Comparison of High‐Speed Optical Observations of a Lightning Flash From Space and the Ground

AbstractWe analyze a nighttime negative cloud‐to‐ground lightning flash in Colombia observed from the ground with a high‐speed camera at 5,000 images per second and from space by the Atmosphere‐Space Interactions Monitor (ASIM) on the International Space Station (ISS), the Lightning Imaging Sensor also on the ISS (ISS‐LIS), and the Geostationary Lightning Mapper (GLM) on GOES‐16. The space instruments measure the oxygen band at 777.4 nm, allowing for direct comparisons of measurements, and the ground‐based camera observes in a wide visible band. After conversion to energy emitted at the cloud top, we find a good linear correspondence of the optical energies measured by the three space instruments, except that GLM values were 3 times higher. We attribute this mainly to the difference in viewing angles between spacecraft and the cloud. Over the entirety of the ASIM observed flash, optical pulses were detected by GLM and LIS, only when the energy reported by ASIM was greater than 332 J and 949 J, respectively. Their detection rate corresponds to 14% and 2.5%, respectively, of the flash duration observed by ASIM. The temporal variation of the high‐speed camera luminosity matched well the features observed by ASIM around the time of the stroke but reached ~3.9 times higher peak intensity during the return stroke, attributed to its broader spectral sensitivity band and a viewing angle advantage.

Pressure Optimized PowEred Respirator (PROPER): A miniaturized wearable cleanroom and biosafety system for aerially transmitted viral infections such as COVID-19

The supply of Personal Protective Equipment (PPE) in hospitals to keep the Health Care Professionals (HCP) safe taking care of patients may be limited, especially during the outbreak of a new disease. In particular, the face and body protective equipment is critical to prevent the wearer from exposure to pathogenic biological airborne particulates. This situation has been now observed worldwide during the onset of the COVID-19 pandemic. As concern over shortages of PPE at hospitals grows, we share with the public and makers’ community the Pressure Optimized PowEred Respirator (PROPER) equipment, made out of COTS components. It is functionally equivalent to a Powered Air Purifying Respirator (PAPR). PROPER, a hood-based system which uses open source and easily accessible components is low-cost, relatively passive in terms of energy consumption and mechanisms, and easy and fast to 3D print, build and assemble. We have adapted our experience on building clean room environments and qualifying the bioburden of space instruments to this solution, which is in essence a miniaturized, personal, wearable cleanroom. PROPER would be able to offer better protection than an N95 respirator mask, mainly because it is insensitive to seal fit and it shields the eyes as well. The PROPER SMS fabric is designed for single-use and not intended for reuse, as they may start to tear and fail but the rest of the parts can be disinfected and reused. We provide a set of guidelines to build a low-cost 3D printed solution for an effective PAPR system and describe the procedures to validate it to comply with the biosafety level 3 requirements. We have validated the prototype of PROPER unit for air flow, ISO class cleanliness level, oxygen and carbon-dioxide gas concentrations during exhalation, and present here these results for illustration. We demonstrate that the area inside the hood is more than 200 times cleaner than the external ambient without the operator and more than 175 times with the operator and in an aerosol exposed environment. We also include the procedure to clean and disinfect the equipment for reuse. PROPER may be a useful addition to provide protection to HCPs against the SARS-CoV-2 virus or other potential future viral diseases that are transmitted aerially.

Integrating Light Curve and Atmospheric Modeling of Transiting Exoplanets

Abstract Spectral retrieval techniques are currently our best tool to interpret the observed exoplanet atmospheric data. Said techniques retrieve the optimal atmospheric components and parameters by identifying the best fit to an observed transmission/emission spectrum. Over the past decade, our understanding of remote worlds in our galaxy has flourished thanks to the use of increasingly sophisticated spectral retrieval techniques and the collective effort of the community working on exoplanet atmospheric models. A new generation of instruments in space and from the ground is expected to deliver higher quality data in the next decade; it is therefore paramount to upgrade current models and improve their reliability, their completeness, and the numerical speed with which they can be run. In this paper, we address the issue of reliability of the results provided by retrieval models in the presence of systematics of unknown origin. More specifically, we demonstrate that if we fit directly individual light curves at different wavelengths (L-retrieval), instead of fitting transit or eclipse depths, as it is currently done (S-retrieval), the said methodology is more sensitive against astrophysical and instrumental noise. This new approach is tested, in particular, when discrepant simulated observations from Hubble Space Telescope/Wide Field Camera 3 and Spitzer/IRAC are combined. We find that while S-retrievals converge to an incorrect solution without any warning, L-retrievals are able to flag potential discrepancies between the data sets.