Space Applications Research Articles

A simulation study of irradiation effect on InAs/GaAsSb type II quantum dot structures

Particles in space cause irradiation damage to the solar cells (SCs), resulting in the degradation of their performance. Quantum dot solar cells (QDSCs) have higher theoretical efficiency and better irradiation resistance than the conventional GaAs SCs, which makes them highly promising for application in space. In this paper, we study the proton irradiation effect on InAs/GaAs0.8Sb0.2 QDSCs by SRIM program. The simulation result shows that the InAs/GaAs0.8Sb0.2 QDSCs have fewer vacancies than GaAs SCs when irradiated with low-energy proton, which indicates that the InAs/GaAs0.8Sb0.2 QDSCs have better anti-irradiation characteristics. The study about displacements per atom and proton concentration in two SCs shows that protons with low energy and high irradiation fluences will cause more serious damage in InAs/GaAs0.8Sb0.2 QDSCs. In addition, the proton incident angle affects the vacancy distribution, while the number of QD layers has little effect on it.

Dielectric characterization using waveguide method for antenna and radome materials in space applications

Dielectric characterization using waveguide method for antenna and radome materials in space applications

Sandwich structures with TPMS core and printed circuit board faces

Sandwich structures are widely used in the aerospace industries due to their mechanical properties that give them high energy absorption, low density, and high mechanical strength. These structures are composed of two faces interspersed by a core that can have various geometric configurations. One of the most widely used geometric cells are honeycomb structures, highly used in structural applications since the early 20th century. However, new geometric core configurations, as well as alternative materials and manufacturing processes, are being studied for space applications. Triply Periodic Minimal Surfaces (TPMS) are lattice structures composed of periodic surface structures in three independent directions. Among the available models, the most notable TPMS structures are Schwartz-type, Diamond-type, and Gyroid-type. Since the structures are too complex to be manufactured by subtractive manufacturing, additive manufacturing is excellent, being able to produce complex structures much faster and easier. One of the most common types of 3D printing is Fused Deposition Modeling (FDM), which is based on the fusion and deposition of various materials, such as thermoplastic materials. To save space and improve the mechanical strength of Cubesats, sandwich structures are being produced using printed circuit boards (PCB) of electrical and electronic components as outer faces. These faces are called laminates and are made of thermosetting materials such as fiberglass and epoxy resin, composites, or ceramic materials. The objective of this paper is to produce sandwich panels, with a core based on the TPMS architecture. They will be printed in thermoplastic material with laminated faces used in printed circuit boards. A numerical analysis using the finite element method was performed and its testing according to ASTM C393, furthermore, this paper aims to realize an optimized TPMS core with mass distribution based on the stress profile and compare them.

Improvement of the thermionic emission properties of C12A7 electride

Calcium aluminate electride (named as C12A7) has become an active topic as a material for electron emission in the research field of electron sources, especially for electric propulsion, in recent years. Whereas the initially predicted, extremely low work function of 0.6 eV could not be confirmed experimentally at technically relevant surface current densities, the material remains an attractive emitter. Besides C12A7 emitting electrons at lower temperatures compared to LaB6, it appears to be resistant to poisoning and even iodine compatible as only known low work function material. On the other hand, the ceramic electride nature of the emitter introduces challenges related to the thermal, mechanical and electrical properties. Therefore, C12A7 has been investigated experimentally as a candidate material for thermionic emitters in space applications. The aim of this study was to enhance the thermionic emission by material modifications such as surface treatments, electrical contacting methods and doping of the C12A7. The performance improvement was quantified in a thermionic diode configuration, in which the emission current was determined as a function of temperature over multiple heating cycles to observe time dependent effects. The surface treatment such as grinding or polishing affects the emission properties of the C12A7 negatively. In contrary, the doping of the C12A7 lattice as well as the contacting of the back side (heater side) significantly improved the emission as well as the measured current density.

Microstrip patch antenna fabricated and simulated results for S-Band, C-band and X-band antenna for space and communication applications

Different Microstrip patch antennas (MPA) designed and used for different applications from medical to wireless technology to satellite applications. Frequency range of S, C and X band are designed with different substrate of FR4 and polyimide. MPA are easy to fabricate in compact form with 4 to 18 array of antennas. Bow-Tie antenna designed for S-Band and an array of compact X-band antenna is designed and analyzed to achieve fixed satellite service (FSS) as shown in figure with band of 7.89 GHz-10.49GHz with gain up to 35dB. Another design with 6 GHz frequency designed with a plan background categorize in C-Band. Third design is with SSR background to simulate the antenna with X band. Antennas have been simulated and the fabricated using chemical etching process and the results were compared. Impedance, S11, gain and directivity were observed with different shapes of antennas at different frequency band. Moreover, the proposed antenna design can be used as an element in an array configuration to achieve high gain in both transmission and reception modes of FSS.

Advances in Atom Interferometry and their Impacts on the Performance of Quantum Accelerometers On-board Future Satellite Gravity Missions

Recent advances in cold atom interferometry have cleared the path for space applications of quantum inertial sensors, whose level of stability is expected to increase dramatically with the longer interrogation times accessible in space. In this study, an in-orbit model is developed for a Mach–Zehnder-type cold-atom accelerometer. Performance tests are realized under different assumptions about the positioning and rotation compensation method, and the impact of various sources of errors on instrument stability is evaluated. Current and future advances for space-based atom interferometry are discussed, and their impact on the performance of quantum sensors on-board satellite gravity missions is investigated in three different scenarios: state-of-the-art scenario (expected to be ready to launch in 5 years), near-future (expected to be launched in the next 10 to 15 years) and far-future scenarios (expected for the next 20 to 25 years). Our results indicate that the highest sensitivity is achievable by positioning the electrostatic accelerometer at the center of mass of the satellite and the quantum accelerometer aside, on the cross-track axis of the satellite. We show that one can achieve a sensitivity level close to 5 × 10−10 m/s2/Hz with the current state-of-the-art technology. We also estimate that in the near and far-future, atom interferometry in space is expected to achieve sensitivity levels of 1 × 10−11 m/s2/Hz and 1 × 10−12 m/s2/Hz, respectively. A roadmap for improvements in atom interferometry is provided that would maximize the performance of future quantum accelerometers, considering their technical capabilities. Finally, the possibility and challenges of having ultra-sensitive atom interferometry in space for future space missions are discussed.

Scaling Laws for the Influence of Gravity and Its Gradient on Dropwise Condensation: A Simulation Study.

Gravity is essential for the shedding of condensed droplets on hydrophobic surfaces, whose influences on condensation parameters under unconventional gravity conditions remain unclear and are hard to probe through experiments. A simulation framework is designed here to investigate such phase-change processes. We find clear scaling laws between heat flux Q, residual volume V, gravitational acceleration g, and nucleation density N0 with Q ∼ g1/6N01/3 and V ∼ g-1/2N00. We also identify a critical gravitational acceleration determined by nucleation density, above which a counterintuitive trend emerges: the heat flux decreases with increasing gravitational acceleration. This deviation is attributed to the sharp decrease in heat flux contributed by droplets larger than the effective radius. In addition, for zero-gravity scenarios, a centrifugal strategy is proposed to simulate Earth's gravity by introducing artificial gravity with a spatial gradient. We reveal that the gradients have a significant influence on the residual volume but a minor one on the heat flux. The conclusions are informative for the estimation and design of condensation heat transfer systems for future space applications.

Comparative analysis of radiation-induced effects on the performance of p-type PERC and TOPCon solar cells for space applications

This work presents a comprehensive numerical evaluation of PERC and TOPCon technologies, focusing on the impact of radiation-induced defects. This assessment is conducted for p-type silicon solar cells as they are intrinsically more resistant to radiation defects. By rigorously calibrating recombination parameters, radiation-induced defect profiles, and other pertinent details, a robust basis is established for an in-depth comparison of the performance characteristics displayed by both architectures under space conditions. The investigation reveals that when utilizing substrates with high doping levels, both PERC and TOPCon cells exhibit nearly identical beginning-of-life (BOL) and end-of-life (EOL) performance. However, with lower substrate doping concentrations, both technologies show improved BOL efficiency. Notably, this enhanced BOL efficiency does not translate into superior EOL efficiency. This distinction in EOL efficiency can be attributed to two primary factors triggered by radiation exposure. Firstly, the emergence of defects leads to a reduction in open-circuit voltage. Secondly, dopant compensation contributes to an increase in series resistance. Specifically, for PERC cells, the challenge of elevated series resistance is further exacerbated by the requirement for majority carriers to traverse both vertically and laterally to reach the rear metal contact. When a robust defect recovery mechanism or resilient cover glass is absent, substrates characterized by lower doping levels display increased susceptibility to the adverse effects of radiation-induced defects and the subsequent dopant compensation. Under these circumstances, the TOPCon technology demonstrates a significant advantage over PERC, particularly for high electron fluence due to its full area contacts for both minority and majority charge carriers.

Design and Implementation of 76W Forward Converter with Dual output to power Up digit unit for space application

Design and Implementation of 76W Forward Converter with Dual output to power Up digit unit for space application

Application of Deaf Space in the Interior of Creativity and Art Center for the Deaf

Application of Deaf Space in the Interior of Creativity and Art Center for the Deaf

Monocular-GPS Fusion 3D object detection for UAVs

Unmanned Aerial Vehicles (UAVs) exhibit superior maneuverability and large-scale movement capability in 3D space, making them ideal platforms for various autonomous applications. However, UAVs with cameras face challenges in 3D situational awareness, which limits their applications in 3D space, particularly in Lake Search and Rescue (LSAR) scenarios. In this paper, we propose a new LSAR Aerial 3D detection dataset (LA3D) and a pioneering end-to-end aerial Monocular-GPS Fusion 3D detector (MGF3D) to improve UAVs’ 3D understanding capability and mitigate the gap between research and real-world application. LA3D is collected by a well-designed hybrid-wing UAV platform on lake surface scenes, which has high-quality annotated 3D bounding boxes, aligned GPS altitudes, and comprehensive metrics. Moreover, MGF3D aggregates multi-modal features with rich geometric and semantic information and feeds them into the 3D detection head for final predictions. To achieve this, we design the Altitude Encoder (AE) module to extract geometric GPS altitude features and introduce Image Encoder (IE) to encode semantic image features respectively. The plug-and-play Monocular-GPS Fusion (MGF) module is proposed to fuse GPS altitude features with image features, which adaptively learns 3D space information and enhances long-distance depth estimation capability. The extensive experiments on the LA3D dataset validate that MGF3D significantly improves aerial 3D detection accuracy. Furthermore, the MGF3D is deployed on a UAV embedded platform to perform the challenging real-world LSAR flight task, demonstrating the effectiveness and practicality of our LA3D and MGF3D. We plan to release the dataset and code in here.

First-principles predictions of structure, half-metallic antiferromagnetism, optoelectronic, and elastic properties of double perovskites A2TaNiO6 (A = Ca, Sr, and Ba) for energy harvesting

In this article, the electronic, half-metallic antiferromagnetism, and optical characteristics of A2TaNiO6 (A = Ca, Sr, and Ba) double perovskites have been investigated by using WIEN2k code with the GGA + PBEsol approximation. The cubic phase structures were optimized with minimum ground state energy. The electronic attributes showed a semiconductor nature for spin-up channels and a metallic nature for spin-down channels, indicating half-metallicity. Magnetic properties have demonstrated the magnetic moments and antiferromagnetic nature of the studied perovskites. The optical response was assessed by examining dielectric function, absorption coefficient, reflectivity, and energy loss function. Higher values of these parameters in the energy range of 2–4 eV suggest their potential for optoelectronics. Mechanical properties have been also investigated which demonstrated that these compounds have outstanding mechanical stability, anisotropy, mechanical strength, and ductility. The collective results reveal the importance of the analyzed compounds as promising candidates for spintronics, photovoltaics in space, UV-photodetectors, and other UV-based optoelectronic applications.

Spacing and nitrogen application affect Indian oregano (Origanum vulgare L.) biomass, essential oil yield and composition

Oregano offers culinary and medicinal applications for mankind. Due to its vast health benefits, its consumption has been gradually rising in the modern era. Since, the nutrients and proper spacing are critical factors influencing plant growth, current study endeavors to investigate the effects of four different nitrogen levels (N0: 0 kg/ha, N1: 50 kg/ha, N2: 100 kg/ha, and N3: 150 kg/ha) combined with three row spacings (S1 = 45 × 45 cm, S2 = 45 × 30 cm, and S3 = 45 × 15 cm) on the growth and production of oregano, with the goal of optimizing nitrogen levels and spacing for effective cultivation of a recently released Indian oregano variety i.e., CIM-Sudeeksha. The study revealed that the N2S2 treatment (i.e., 100 kg/ha nitrogen and 45 × 30 cm spacing) produced the tallest plants, measuring 63.60±0.79 cm. On the other hand, the N2S3 treatment (i.e., 45×15 cm spacing and 100 kg/ha nitrogen) resulted with the remarkable yields of both fresh and dry herbs and oil, measuring 292.23±2.03 (Fresh herb) and 73.04±2.61 (dry herb) q/ha, 63.37±5.27 (Fresh herb oil), and 56.14±4.14 (Dry herb oil) kg/ha respectively, whereas N3S3 treatment showed highest but insignificantly different dry herb oil content i.e., 56.32±2.42 kg/ha. Also, the chemical composition of N2S2 treatment showed more carvacrol content (56.89 % in fresh and 52.62 % in dry herb) then N2S3 and N3S3 treatment. The results showed that the effects of nitrogen application with rates of 100 kg/ha and 150 kg/ha were similar on almost all agronomic traits and oil yield parameters. Furthermore, the 45×30 cm spacing showed encouraging outcomes, increasing vegetative growth and decreasing plant competition. Given these findings, it is advised to use 45×30 cm spacing and 100 kg/ha nitrogen fertilization for increased Indian oregano production and economical resource utilization.

Cosmo ArduSiPM: An All-in-One Scintillation-Based Particle Detector for Earth and Space Application.

Thanks to advancements in silicon photomultiplier sensors (SiPMs) and system-on-chip (SoC) technology, our INFN Roma1 group developed ArduSiPM in 2012, the first all-in-one scintillator particle detector in the literature. It used a custom Arduino Due shield to process fast signals, utilizing the Microchip Sam3X8E SoC's internal peripherals to control and acquire SiPM signals. The availability of radiation-tolerant SoCs, combined with the goal of reducing system space and weight, led to the development of an innovative second-generation board, a better-performing device called Cosmo ArduSiPM, suitable for space missions. The architecture of the new detector is based on the Microchip SAMV71 300 MHz, 32-bit ARM® Cortex®-M7 (Microchip Technology Inc., Chandler, AZ, USA). While the analog front-end is essentially identical to the ArduSiPM, it utilizes components with the smallest possible package. The board fits in a CubeSat module. Thanks to the compact design, the board has two independent channels, with a total weight of only 40 grams within a CubeSat form factor. The ArduSiPM architecture is based on a single microcontroller and fast discrete analog electronics. It benefits from the continued development of SoCs related to the IoT (Internet of Things) market. Compared with a system with a custom ASIC, this architecture based on software and SoC capabilities offers considerable advantages in terms of cost and development time. The ability to incorporate new commercial SoCs, continuously emerging from advancements in the aerospace and automotive industries, provides the system with a robust foundation for sustained growth over the years. A detailed characterization of the hardware and the system's response to different photon fluxes is presented in this article. Additionally, coupling the device with a scintillator was tested at the end of this article as a preliminary trial for future measurements, showing potential for further enhancement of the detector's capabilities.

Enhancing Wear Resistance and Mechanical Behaviors of AA7020 Alloys Using Hybrid Fe3O4-GNP Reinforcement

This study investigates the effect of graphene nanoplatelets (GNPs) and milling duration on the microstructure, mechanical properties, and wear resistance of the AA7020 alloy reinforced with Fe3O4 and GNP. The composites were prepared with a fixed 10 wt.% Fe3O4 and varying GNP contents (0.5 and 1 wt.%) using high-energy ball milling for 4 and 8 h, followed by hot pressing. The aim was to enhance the performance of the AA7020 alloy for potential use in defense, automotive, aviation, and space applications, where superior mechanical properties and wear resistance are required. The results showed that the incorporation of 0.5 wt.% GNP and optimized milling significantly improved the composite’s performance. The AA7020 + 10 wt.% Fe3O4 + 0.5 wt.% GNP composite achieved the highest density (99.70%) when milled for 4 h. Its hardness increased with both the inclusion of GNP and extended milling duration, with the composite milled for 8 h exhibiting the highest hardness value (149 HBN). The tensile strength also improved, with the composite milled for 4 h showing a 28% increase (292 MPa) compared with the unreinforced alloy. Additionally, the friction coefficient decreased with GNP content and milling duration, with the composite milled for 8 h showing a 26% reduction. Wear resistance was notably enhanced, with the composite milled for 8 h exhibiting the lowest specific wear rate (7.86 × 10−7 mm3/Nm).

Flexible Solid-Electrolyte-Gated-Dielectric Carbon Nanotube Thin Film Transistors and Integrated Circuits with the Recorded Radiation Tolerance and Reparability.

Radiation-tolerance and repairable flexible transistors and integrated circuits (ICs) with low power consumption have become hot topics due to their wide applications in outer space, nuclear power plants, and X-ray imaging. Here, we designed and developed novel flexible semiconducting single-walled carbon nanotube (sc-SWCNT) thin-film transistors (TFTs) and ICs. Sc-SWCNT solid-electrolyte-gate dielectric (SEGD) TFTs showcase symmetric ambipolar characteristics with flat-band voltages (VFB) of ∼0 V, high ION/IOFF ratios (>105), and the recorded irradiation resistance (up to 22 Mrad). Moreover, flexible sc-SWCNT ICs, including CMOS-like inverters and NAND and NOR logic gates, have excellent operating characteristics with low power consumption (≤8.4 pW) and excellent irradiation resistance. Significantly, sc-SWCNT SEGD TFTs and ICs after radiation with a total irradiation dose (TID) ≥ 11 Mrad can be repaired after thermal heating at 100 °C. These outstanding characteristics are attributed to the designed device structures and key core materials including SEGD and sc-SWCNT.

Effect of Gamma Irradiation on the Structure, Morphology, and Memristive Properties of CVD Grown ReS2 Thin Film

AbstractIn this work, effect of gamma irradiation on chemical vapor deposition grown ReS2 thin films vis‐a‐vis change in its structure, morphology, chemical composition, and memristive behaviour is reported to assess its radiation hardness for space applications. High‐resolution transmission electron micrographs and selected area electron diffraction pattern infer polycrystalline to amorphous phase transition and increase in the number of grain boundaries (GBs) after exposure to 25 kGy of gamma radiation. X‐ray photoelectron spectroscopy and low‐temperature photoluminescence measurements reveal the formation of sulfur vacancies (SV) accompanied with partial oxidation of film. Memristors are then fabricated on the as‐grown film using different metal electrodes, which are Ag, Pt, and Ti in lateral geometry, and their resistive switching (RS) mechanism is studied along with the impact of gamma irradiation. RS is attributed to the formation of conducting filaments due to GB‐mediated migration of metal ions, SV, and oxygen ions from the partially oxidized film. Furthermore, irradiation is found to increase current in the high resistance state of the device, which subsequently reduces the memory window. This impact is observed to be consistent across all the devices which validates the effect of irradiation irrespective of the nature of the metal electrode used.

Analysis of deformation in tensegrity structures with curved compressed members

Tensegrity structures are prestressed structures consisting of compressed members connected by prestressed tensioned members. Due to their properties, such as flexibility and lightness, mobile robots based on these structures are an attractive subject of research and are suitable for space applications. In this work, a mobile robot based on a tensegrity structure with two curved members connected by eight tensioned strings is analyzed in terms of deformation in the curved members. Further, the difference in locomotion trajectory between the undeformed and deformed structure after the prestress is analyzed. For that, the theory of large deflections of rod-like structures is used. To determine the relationship between acting forces and the deformation, the structure is optimized using minimization algorithms in Python. The results are validated by parameter studies in FEM. The analysis shows that the distance between the two curved members significantly influences the structure’s locomotion. It can be said that the deformation of the components significantly influences the locomotion of tensegrity structures and should be considered when analyzing highly compliant structures.

DEVELOPMENT OF THE DEVICE FOR CONTROLLING AND MEASURING THE SUPPLY OF WORKING GAS FOR LABORATORY TESTING OF THE ELECTRIC PROPULSION THRUSTERS

The object of the research is a device for measuring, controlling, and indicating the flow rate of working gas during laboratory testing of electric propulsion systems for space applications. The problem lies in the need to ensure high accuracy in controlling and measuring the flow rates of working gas for such devices. The obtained results include: analysis of existing industrial flow meters that could be used in development; proposed structural and functional diagrams of the device; experimental investigations into the accuracy of the developed device. Based on the analysis of parameters of the most common flow meters for development, the Bronkhorst F-201CV-100-AAD-22-V regulator was selected. Based on the selected regulator, a device was developed with a 32-bit ARM architecture. This architecture provides for the use of floating-point calculations, easy reprogramming of the device, and fast indication of values displayed on the indicator. The device features galvanic isolation between the control bus and the UART port of the microcontroller. The device allows for regulation, measurement, and indication of the flow rate of working gas into the anode block and hollow cathode during testing of Hall thrusters. Using the device allows for recommendations regarding the design of onboard systems for supplying working fluid to electric rocket propulsion systems. Based on the presented development and conducted research, laboratory prototypes of the devices were manufactured. The measurement error throughout the entire range of working gas flow rates does not exceed 0.7%. The overall error of the stand control and measurement system for working gas flow rates is up to 3%. The developed device provides measurement accuracy that satisfies the developers of electric propulsion systems.

Electron-Induced Single-Event Effect in 28 nm SRAM-Based FPGA

As the feature size of integrated circuit decreases, the critical charge of single-event effect decreases as well, making nano-scale devices more susceptible to the high-energy charged particles during their application in space. Here, we study the electron-induced single-event effect in 28 nm static random-access memory (SRAM)-based field programmable gate array (FPGA) utilizing high-energy electrons with energy of 1 MeV~5 MeV. The experimental results demonstrate that the 3 MeV electrons can cause single-event functional interrupts (SEFIs) in FPGA, while the electrons with other energies cannot. To further explore the mechanism of electron-induced SEFIs in this nanoscale FPGA, we combined Monte Carlo, Technology Computer-Aided Design (TCAD), and Simulation Program with Integrated Circuit Emphasis (SPICE) simulations. It is revealed that the SEFI was mainly caused by the direct ionization effect of high-energy electrons, and the SEFI was related to the interactions between multiple sensitive nodes.