Space Applications Research Articles

A 1 K-Class Cryogenic System and its Coupling With SNSPD for Space Applications

A 1 K-Class Cryogenic System and its Coupling With SNSPD for Space Applications

Convective boiling heat transfer enhancement via femtosecond laser textured inclined microfeatures

Designing efficient cooling devices is crucial in a multitude of applications. Although cooling technologies have existed for decades, there is a lack of efficient heat dissipation methods, especially for space applications where thermal management devices must dissipate heat in reduced gravity and where convective boiling heat transfer is frequently employed. In this framework, we evaluate the change in bubble production for different types of surface textures produced on 200 µm thick 316L SS foils using a femtosecond laser. The investigated textures include microscale grooves and conical holes with tilted (= 45°) geometry. In addition, we also evaluate the effect of laser-induced periodic surface structures (LIPSS), which are sub-micron scale features fabricated by fs laser processing. The fluid used is PP1, a replacement of 3M™ FC-72 in heat transfer applications.

Reliability modelling and assessment of CMOS image sensor under radiation environment

The Complementary Metal-Oxide Semiconductor (CMOS) image sensor is a critical component with the function of providing accurate positioning in many space application systems. Under long-time operation in space environments, there are radiation related degradation and various uncertainties affecting the positioning accuracy of CMOS image sensors, which further leads to a reliability reduction of CMOS image sensors. Obviously, the reliability of CMOS image sensors is related to their specified function, degradation, and uncertainties; however, current research has not fully described this relationship. In this paper, a comprehensive approach to reliability modelling of CMOS image sensors is proposed based on the reliability science principles. Firstly, the performance margin modelling of centroid positioning accuracy is conducted. Then, the degradation model of CMOS image sensors is derived considering the dark current increase induced by the total ionizing dose effects. Finally, various uncertainties are analyzed and quantified, and the measurement equation of reliability is proposed. A case study of a CMOS image sensor is conducted to apply the proposed method, and the sensitivity analysis can provide suggestions for design and use of CMOS image sensors to ensure reliability. A simulation study is conducted to present the advantages of the proposed comprehensive approach.

Next-generation materials for space electronics: A conceptual review

Space electronics play a pivotal role in enabling modern space missions, facilitating communication, navigation, remote sensing, and scientific exploration. However, the extreme conditions of space, including temperature variations, radiation exposure, and mechanical stresses, pose significant challenges for the materials used in electronic components. This conceptual review explores the next-generation materials for space electronics, aiming to address these challenges and push the boundaries of performance and reliability. The review begins by outlining the fundamental requirements for space electronics materials, emphasizing the need for extreme temperature resistance, radiation shielding, mechanical strength, and thermal conductivity. It then surveys the current state-of-the-art materials, including silicon-based materials, compound semiconductors, polymers, ceramics, and composites, highlighting their strengths and limitations in space applications. Furthermore, the review discusses emerging materials and technologies, such as 2D materials, organic electronics, quantum materials, and metamaterials, which hold promise for revolutionizing space electronics. Implementation strategies are proposed, considering factors like integration with existing systems, scalability, cost-effectiveness, environmental impact, and regulatory compliance. Through this conceptual review, insights are provided into the potential applications of next-generation materials in satellites, space probes, exploration missions, and beyond. The conclusion summarizes key findings, underscores potential implications for the future of space electronics, and offers recommendations for further research and development. By advancing the state of materials science for space electronics, this review aims to contribute to the ongoing exploration and utilization of space for the benefit of humanity.

Visual Water: An Integration of App and Web to Understand Chemical Elements

This paper presents Visual Water: a novel inter- active application designed to augment chemical education and discovery. This mobile app and web version collectively provides an interactive environment for users to explore and understand chemical elements. Using vast databases and visual interfaces, Visual Water provides real-time information about various chem- ical elements, leading to a range of new, engaging and accessible learning tools for students, educators and enthusiasts. This paper provides a description of the development of this system, key features and potential impact of the Visual Water system in helping users better understand chemical reactions and their application in formal and informal educational spaces.

GPS-Based Precise Orbit Determination of LEO Satellites Using Space-Based Double-Differenced Observations

One of the important GPS applications in space is precise orbit determination (POD) of Low-Earth Orbit (LEO) satellites. Thousands of LEO satellites are currently in orbit. One of the challenges is how to efficiently and precisely determine the orbits to satisfy the relative and absolute accuracy needs of missions. Currently, GPS-based POD of LEO satellites can be performed using either un-differenced (UD) or ground-based double-differenced (DD) observations. The UD POD needs both precise GPS satellite orbits and clocks; the DD POD needs not only the precise orbits, but also global ground reference receivers. Therefore, the GPS-based LEO POD is based on either global ground stations or precise GNSS clocks, which are not convenient for near real-time or real-time data processing. The GPS orbits can be precisely predicted in certain time; the clocks are not. For some formation flying satellite missions (two or more LEO satellites), the absolute orbit accuracy requirements are not as stringent as the relative requirements. The problem is how to perform LEO POD without global station data and precise GPS clocks in near real-time or real-time to achieve the mission orbit accuracy requirement. Based on this motivation, we investigated the GPS-based LEO POD using space-based DD observations without using global ground station GPS data and precise GPS clock products. For this study, we processed the real GPS observations from two LEO satellites. The absolute and relative orbit accuracy is assessed using several tests, including analysis of the orbit fits, external orbit comparisons, Satellite Laser Ranging (SLR) and K-band Ranging (KBR) residuals.

Shape memory behavior of 4D printed CF/PEKK high temperature composite under subsequent thermomechanical cycles

Shape memory effect (SME) in high temperature polymers (HTPs) has great significance in space for making self-deployable structures, needing high strength and stiffness during operation, signifying the necessity of exploring HTP composite with SME. This work investigates the SME of 4D printed carbon fiber/polyether ketone ketone (CF/PEKK) HTP composite under subsequent thermomechanical cycles for the first time. Scanning electron microscopy (SEM) revealed a uniform distribution of CFs in the developed composite, the extruded composite filament, and the composite prints with seamless raster and layer deposition, confirming a suitable selection of processing parameters. The CF/PEKK composite prints exhibited an excellent shape fixity, Rf = 90 % and 91 %, and shape recovery, Rr = 96 % and 89 % in the first and the tenth cycle, respectively. A significant loss of 7 % in Rr is observed in the tenth cycle. Glass transition (Tg) and degradation temperature (Td) of the CF/PEKK composite prints are observed to be 162 °C and 568 °C, while storage modulus is found 157.69 % and 38.69 % higher than the existing PEKK and PEEK, respectively. This study revealed an excellent SME of 4D printed CF/PEKK composite with outstanding Tg and Td, showing great potential for space applications.

Single-Image Super-Resolution Method for Rotating Synthetic Aperture System Using Masking Mechanism

The emerging technology of rotating synthetic aperture (RSA) presents a promising solution for the development of lightweight, large-aperture, and high-resolution optical remote sensing systems in geostationary orbit. However, the rectangular shape of the primary mirror and the distinctive imaging mechanism involving the continuous rotation of the mirror lead to a pronounced decline in image resolution along the shorter side of the rectangle compared to the longer side. The resolution also exhibits periodic time-varying characteristics. To address these limitations and enhance image quality, we begin by analyzing the imaging mechanism of the RSA system. Subsequently, we propose a single-image super-resolution method that utilizes a rotated varied-size window attention mechanism instead of full attention, based on the Vision Transformer architecture. We employ a two-stage training methodology for the network, where we pre-train it on images masked with stripe-shaped masks along the shorter side of the rectangular pupil. Following that, we fine-tune the network using unmasked images. Through the strip-wise mask sampling strategy, this two-stage training approach effectively circumvents the interference of lower confidence (clarity) information and outperforms training the network from scratch using the unmasked degraded images. Our digital simulation and semi-physical imaging experiments demonstrate that the proposed method achieves satisfactory performance. This work establishes a valuable reference for future space applications of the RSA system.

Effects of gamma-ray irradiation on material and electrical properties of AlN gate dielectric on 4H-SiC

This article investigates the radiation effects on as-deposited and annealed AlN films on 4H-SiC substrates under gamma-rays. The AlN films are prepared using plasma-enhanced-atomic-layer-deposition on an n-type 4H-SiC substrate. The AlN/4H-SiC MIS structure is subjected to gamma-ray irradiation with total doses of 0, 300, and 600 krad(Si). Physical, chemical, and electrical methods were employed to study the variations in surface morphology, charge transport, and interfacial trapping characteristics induced by irradiation. After 300 krad(Si) irradiation, the as-deposited and annealed samples exhibit their highest root mean square values of 0.917 nm and 1.190 nm, respectively, which is attributed to N vacancy defects induced by irradiation. Under irradiation, the flatband voltage (V fb) of the as-deposited sample shifts from 2.24 to 0.78 V, while the annealed sample shifts from 1.18 to 2.16 V. X-ray photoelectron spectrum analysis reveals the decomposition of O-related defects in the as-deposited AlN and the formation of Al(NO x ) y compounds in the annealed sample. Furthermore, the space-charge-limits-conduction (SCLC) in the as-deposited sample is enhanced after radiation, while the barrier height of the annealed sample decreases from 1.12 to 0.84 eV, accompanied by the occurrence of the SCLC. The physical mechanism of the degradation of electrical performance in irradiated devices is the introduction of defects like N vacancies and O-related defects like Al(NO x ) y . These findings provide valuable insights for SiC power devices in space applications.

Nanotechnology applications in interior design of hospitals to enhance thermal comfort and decrease the infection spread for the occupants

Background In healthcare facilities, the significance of sensitive architecture cannot be overstated. In regions facing challenges such as Egypt, the healthcare sector is grappling with deteriorating conditions. The design of hospitals is crucial for addressing the needs of patients with varying illnesses and for creating an environment that fosters psychological well-being. The interior design process, especially the selection of materials, plays a pivotal role in ensuring a hygienic and safe environment within healthcare facilities. Walls, floors, ceilings, and furniture materials are key elements that contribute to the overall design. A study was conducted to investigate the application of nano materials in healthcare facility interior design in Egypt. Methods The study involved first a literature review on nano technology and its application in healthcare interior spaces. It culminated in a framework and guidelines for nano materials in different hospital zones. The analytical part of the study analysed successful international examples, leading to a checklist of nanomaterials categorized by hospital zones. The third part involved a base case study in Alexandria, Egypt, simulating the impact of nano coatings on air temperature, radiant temperature, and relative humidity using the DesignBuilder software. Results The results demonstrated a positive impact on patient health and thermal comfort with nano materials. The use of nano coatings in interior design finishes resulted in decreases in air temperature, radiant temperature, and relative humidity. There was an average decrease of 12.3%-16.7% in air temperature, 3%-4.2% in radiant temperature, and 7%-12% in relative humidity throughout the year. Conclusions The study highlighted the effectiveness of nano technology in enhancing the interior finishes of healthcare buildings, leading to improved patient health, thermal comfort, and decreased infection spread rate. We provide valuable recommendations for optimizing material selection in existing hospital buildings in emphasizing potential benefits of nano materials in healthcare facility design.

Study on the single-event burnout mechanism of p-GaN gate AlGaN/GaN HEMTs

In this work, the single-event burnout (SEB) mechanism of p-GaN gate AlGaN/GaN HEMTs has been studied systematically. The irradiation experiment was carried out based on Ta ions with high linear energy transfer of 75.4 MeV/(mg/cm2), a standard criterion for commercial space applications. It is clearly observed that both the drain current and gate current increase during the irradiation. With the increasing drain bias, the device burns out eventually. Technology computer-aided design simulation was used to explore the possible burnout mechanism. The local high electric field peak induced by the electron and hole redistribution was proposed to explain the permanent damage. When heavy ions impact the device, electron–hole pairs are formed. With the aid of a horizontal electric field across the channel, electrons and holes move toward the drain and gate, respectively. The accumulation of electrons and holes around the drain edge and gate edge induces the local high electric field, which is even higher than the intrinsic breakdown electric field of GaN and AlGaN. The scanning electron microscope results verified the proposed SEB mechanism. This research offers significant theoretical and experimental insights for evaluating the reliability of GaN power devices against high-energy single-event burnout in aerospace applications.

Quantifying regional variability of machine-learning-based snow water equivalent estimates across the Western United States

Seasonal snow-derived water is a critical component of the water supply in the mountains and downstream regions, and the accurate characterization of available water in the form of snow-water-equivalent (SWE), peak SWE, and snowmelt onset are essential inputs for water management efforts. Arising from recent advancements in artificial intelligence (AI) and machine learning (ML), we introduce a large-scale ML SWE model leveraging publicly available data sources and open-source software. The model demonstrates the application of a limited feature space in a relatively simple ML architecture without the need for process-based formulations to effectively estimate spatially continuous SWE at a daily temporal resolution. Beginning with in situ SWE measurements (i.e., SNOTEL), lidar-derived terrain features, and temporal variables, we employ localized feature engineering and optimization via gradient-boosting decision trees to identify regionally unique drivers of snowpack dynamics and use the optimal features to train regionally independent artificial neural networks to estimate regional SWE at a 1 km spatial resolution. The model results yield respectable skill in reconstructed 1 km gridded SWE magnitudes in a hindcast simulation of the 2019 water year that is independent of the training and testing data. Comparing model estimates to over 6200 observations, the model demonstrates a weighted RMSE of 15.4 cm, Kling-Gupta Efficiency metric of 0.86, and a percent bias of 0.71% across 23 snow-influenced regions in the western U.S. The model simulation produces peak SWE estimates within 10 cm for twenty of the twenty-three regions, demonstrating capability in effectively capturing regional snow accumulation processes. The demonstration of low-error ML workflows capable of providing near-real-time, spatially continuous SWE estimates at a high spatial resolution provides proof-of-concept and a foundation to effectively update snow state variables that drive water supply forecasts in snow-dominated regions.

Comparative study: AutoDPR-SEM for enhancing CNN reliability in SRAM-based FPGAs through autonomous reconfiguration

Convolutional neural networks (CNNs) are widely adopted in safety-critical systems, including space applications and autonomous vehicles. Field-programmable gate arrays (FPGAs) based on SRAM are preferred for accelerating CNN computations due to their unique characteristics. However, the configuration memory of FPGAs is susceptible to single event effects (SEEs), which can corrupt computations and lead to misclassification of CNN outputs. In this study, we investigated the impact of SEEs on SRAM-based FPGAs with Two-Photon Absorption (TPA) laser fault injections through a comparative analysis of two popular CNN acceleration architectures: streaming architecture (SA) and single compute engine (SCE). Experimental results show that SA-based CNNs require more hardware resources but exhibit superior resilience against single event upsets (SEUs). Without any Radiation Hardened by Design (RHBD) protection, SCE has an error rate approximately twice as high as SA. To mitigate errors, the Xilinx IP core - Soft Error Mitigation (SEM) is used for error detection and correction, leading to error rate reductions of up to 50 % in both architectures. Importantly, we propose the AutoDPR-SEM (Autonomous Dynamic Partial Reconfiguration for Soft Error Mitigation) approach, which automatically reconfigures the SEM IP core when it remains idle due to uncorrectable errors. AutoDPR-SEM significantly improves CNN error rates, reducing errors by approximately 17.8 times in SCE and 14.8 times in SA. We also applied software level simulation to validate the TPA experiment, showing similar trends of the testing results across all models. In conclusion, the study confirms the feasibility of AutoDPR-SEM in both architectures, showcasing its potential to improve CNN error rates in safety-critical systems.

The inviscid incompressible limit of Kelvin–Helmholtz instability for plasmas

Introduction: The Kelvin–Helmholtz Instability (KHI) is an interface instability that develops between two fluids or plasmas flowing with a common shear layer. KHI occurs in astrophysical jets, solar atmosphere, solar flows, cometary tails, planetary magnetospheres. Two applications of interest, encompassing both space and fusion applications, drive this study: KHI formation at the outer flanks of the Earth’s magnetosphere and KHI growth from non-uniform laser heating in magnetized direct-drive implosion experiments. Here, we study 2D KHI with or without a magnetic field parallel to the flow. We use both the GAMERA code, which solves the compressible Euler equations, and the STRATOSPEC code, which solves the Navier-Stokes equations under the Boussinesq approximation, coupled with the magnetic field dynamics. GAMERA is a global three-dimensional MHD code with high-order reconstruction in arbitrary nonorthogonal curvilinear coordinates, which is developed for a large range of astrophysical applications. STRATOSPEC is a three-dimensional pseudo-spectral code with an accuracy of infinite order (no numerical diffusion). Magnetized KHI is a canonical case for benchmarking hydrocode simulations with extended MHD options.Methods: An objective is to assess whether or not, and under which conditions, the incompressibility hypothesis allows to describe a dynamic compressible system. For comparing both codes, we reach the inviscid incompressible regime, by decreasing the Mach number in GAMERA, and viscosity and diffusion in STRATOSPEC. Here, we specifically investigate both single-mode and multi-mode initial perturbations, either with or without magnetic field parallel to the flow. The method relies on comparisons of the density fields, 1D profiles of physical quantities averaged along the flow direction, and scale-by-scale spectral densities. We also address the triggering, formation and damping of filamentary structures under varying Mach number or Atwood number, with or without a parallel magnetic field.Results: Comparisons show very satisfactory results between the two codes. The vortices dynamics is well reproduced, along with the breaking or damping of small-scale structures. We end with the extraction of growth rates of magnetized KHI from the compressible regime to the incompressible limit in the linear regime assessing the effects of compressibility under increasing magnetic field.Discussion: The observed differences between the two codes are explained either from diffusion or non-Boussinesq effects.

Fused Filament Fabrication of Polyethylene/Graphene Composites for In-Space Manufacturing.

Graphene-based composite materials are highly sought after for space applications due to their ability to encompass various properties, such as electrical conductivity, thermal resistance, and radiation shielding. This versatility allows for the creation of multifunctional components that can serve various purposes in space. Three-dimensional (3D) printing of composite materials in space offers a versatile and efficient means of manufacturing components, tools, and structures that are tailored to the unique challenges and requirements of space missions. In this work, we aim to develop 3D-printed composites made of medium-density polyethylene (MDPE) matrix and exfoliated graphene nanoplatelets (xGnP) as filler, using fused filament fabrication (FFF). Our research focuses on the challenges associated with the FFF process for fabricating MDPE/xGnP materials, particularly by optimizing filament extrusion and assessing the resulting material properties and space environmental compatibility. Firstly, we optimize the extrusion process, and use the MDPE/xGnP filaments to fabricate 3D-printed samples after defining the FFF parameters. We employ differential scanning calorimetry (DSC) to assess the melting properties and crystallization degree of the extruded filaments and 3D-printed samples, providing insights into the relationship between these properties and the characteristics of the initial powders. Electrical and tensile tests are carried out to evaluate the material properties after successfully mitigating challenges, such as warping and inadequate adhesion, to build plates during the printing process. Finally, we subject the 3D-printed composites to outgassing tests under exposure to the AM0 solar spectrum to evaluate their space environmental suitability. The results of this work demonstrate the capability of the FFF-based process to efficiently manufacture components made of MDPE/xGnP composites, providing optimized parameters for their potential in-space fabrication.

Effects of Subsurface Drainage Spacing and Organic Fertilizer Application on Alfalfa Yield, Quality, and Coastal Saline Soil

Effects of Subsurface Drainage Spacing and Organic Fertilizer Application on Alfalfa Yield, Quality, and Coastal Saline Soil

Field-balancing alignment of the secondary mirror of space telescope using a self-calibrated model

In-orbit alignment of the secondary mirror (SM) of deployable space telescopes is crucial for high-resolution imaging. Traditional alignment methods, which typically involve dedicated wavefront sensors or numerous iterations to optimize a metric function, are not well-suited for space applications. In this paper, an improved model-based SM alignment method is proposed. The term model refers to the relationship between misalignments and a metric function. The improved method offers two advantages over the previous model-based method in [12]. Firstly, our method allows for self-calibration of the model without the need for an additional wavefront sensor, which greatly simplifies the calibration process. Secondly, our method enables field-balancing alignment of the SM with several correction cycles. The exposure number is only six in one correction cycle and is regardless of the number of FOV sampling points, making it highly efficient for telescopes with a large FOV. The feasibility and performance of our method are verified by simulation. A comparison with existing methods is also given to show the advantages of our method in convergence speed and accuracy.

X-ray Induced Electric Currents in Anodized Ta2O5: Towards a Large-Area Thin-Film Sensor.

We investigated the characteristics of radiation-induced current in nano-porous pellet and thin-film anodized tantalum exposed to kVp X-ray beams. We aim at developing a large area (≫cm2) thin-film radiation sensor for medical, national security and space applications. Large area (few cm2) micro-thin Ta foils were anodized and coated with a counter electrode made of conductive polymer. In addition, several types of commercial electrolytic porous tantalum capacitors were assembled and prepared for irradiation with kVp X-rays. We measured dark current (leakage) as well as transient radiation-induced currents as a function of external voltage bias. Large transient currents (up to 50 nA) under X-ray irradiation (dose rate of about 3 cGy/s) were measured in Ta2O5 capacitors. Small nano-porous Ta and large-area flat Ta foil capacitors show similar current-voltage characteristic curve after accounting for different X-ray attenuation in capacitor geometry. The signal is larger for thicker capacitor oxide. A non-negligible signal for null external voltage bias is observed, which is explained by fast electron production in Ta foils. Anodized tantalum is a promising material for use in large-area, self-powered radiation sensors for X-ray detection and for energy harvesting.

A 2.5V In-Plane Flexi-Pseudocapacitor with Unprecedented Energy and Cycling Efficiency for All-Weather Applications.

As electronic devices for aviation, space, and satellite applications become more sophisticated, built-in energy storage devices also require a wider temperature spectrum. Herein, an all-climate operational, energy and power-dense, flexible, in-plane symmetric pseudocapacitor is demonstrated with utmost operational safety and long cycle life. The device is constructed with interdigital-patterned laser-scribed carbon-supported electrodeposited V5O12·6H2O as a binder-free electrode and a novel high-voltage anti-freezing water-in-salt-hybrid electrolyte. The anti-freezing electrolyte can operate over a wide temperature range of -40-60°C while offering a stable potential window of ≈2.5V. The device undergoes rigorous testing under diverse environmental conditions, including rapid and regular temperature and mechanical transition over multiple cycles. Additionally, detailed theoretical simulation studies are performed to understand the interfacial interactions with the active material as well as the local behavior of the anti-freeze electrolyte at different temperatures. As a result, the all-weather pseudocapacitor at 1Ag-1 shows a high areal capacitance of 234.7mFcm-2 at room temperature and maintains a high capacitance of 129.8mFcm-2 even at -40°C. Besides, the cell operates very reliably for over 80950 cycles with a capacitance of 25.7mFcm-2 at 10Ag-1 and exhibits excellent flexibility and bendability under different stress conditions.

Self-Healing Transparent Poly(dimethyl)siloxane with Tunable Mechanical Properties: Toward Enhanced Aging Materials for Space Applications.

When exposed to the geostationary orbit, polymeric materials tend to degrade on their surface due to the appearance of cracks. Implementing the self-healing concept in polymers going to space is a new approach to enhancing the lifespan of materials that cannot be replaced once launched. In this study, the elaboration of autonomous self-healing transparent poly(dimethylsiloxane) (PDMS) materials resistant to proton particles is presented. The PDMS materials are functionalized with various compositions of urea and imine moieties, forming dynamic covalent and/or supramolecular networks. The hydrogen bonds induced by the urea ensure the formation of a supramolecular network, while the dynamic covalent imine bonds are capable of undergoing exchange reactions. Materials with a broad range of mechanical properties were obtained depending on the composition and structure of the PDMS networks. As coating applications in a spatial environment were mainly targeted, the surface properties of the polymer are essential. Thus, percentages of scratch recovery were determined by AFM. From these data, self-healing kinetics were extracted and rationalized based on the polymer structures. The obtained data were in good agreement with the relaxation times determined by rheology in stress relaxation experiments. Moreover, the accelerated aging of materials under proton irradiation, simulating a major part of the geostationary environment, revealed a strong limitation or disappearance of cracks while keeping the transparency of the PDMS. These promising results open routes to prepare new flexible autonomous polymeric materials for space applications.