Small Satellite Research Articles

Lithium-ion cells for space applications: Aspects of durability

Lithium-ion cells (LIC) are emerging as the critical energy source in space applications for spacecraft. The analysis of the failure of small satellites reveals that 41.3% have either suffered partial or total failures in the space environment around Earth, resulting in the accumulation of debris. The defects in batteries caused more failures than thrusters. The present paper details a framework for ensuring the durability of LIC systems in space applications. It is discussed in three verticals viz. a) Durability through Design' that gives prominence to best practices in cell chemistry selection, processing and, design through parametric modelling; b) 'Durability through quality control and testing by the manufacturer and by identifying relevant reliability models; c)'On-orbit management' through the State of Health (SOH) assessment by Random Forest algorithm and a well-equipped intelligent Battery Management System (BMS). Lacuna in standards for cell development process is brought out. Importance of quantitative approach for design, reliability and asset management during space application is highlighted. Use of agile, contemporary techniques of artificial intelligence in this quantitative approach is also discussed. The framework tries to bring out a systematized protocol to be followed during the development and operational life cycle of LIC for ensuring highly reliable systems for space application.

In-Orbit FPGA reprogramming device for small satellites

Development of satellite technologies is a challenging task, which includes design, manufacturing, testing, and in-orbit operation stages. The reliability of each subsystem shall be at the highest level since space has severe environmental conditions and most satellites do not have an opportunity to perform repairment or replacement of their hardware components.In-orbit reprogramming of some devices, such as On-board Computer (OBC), Attitude Control Unit (ACU), and Power Control Unit (PCU) can provide great advantages to a mission by extending the lifetime and performance of a satellite's operation. At the same time, even a small mistake can result in a lot of monetary losses or even failure of a subsystem or the whole project. So, a reprogramming method to be used in space missions shall undergo excessive testing to provide high reliability for updating software in orbit.This paper is devoted to an investigation of available and applicable methods for remote reprogramming of Field-Programmable Gate Array (FPGA) based subsystems.A commercial off-the-shelf (COTS) single board computer (SBC) was used as a standalone subsystem to perform reprogramming of a target device. The SBC was tested extensively and reinforced for ensuring its space-compatibility. Several open-source software-based solutions were considered. Some of them are applicable to a wide range of processor architectures, including ARM. Considered methods could reconfigure an FPGA successfully with some major limitations, which were also described in the paper.Based on the investigation, Xilinx Software Command-line Tool (XSCT) was selected as a reprogramming method for ACU of the latest satellite of iQPS, QPS-SAR-2 (“IZANAMI”).

Satellite Image Compression Guided by Regions of Interest

Small satellites empower different applications for an affordable price. By dealing with a limited capacity for using instruments with high power consumption or high data-rate requirements, small satellite missions usually focus on specific monitoring and observation tasks. Considering that multispectral and hyperspectral sensors generate a significant amount of data subjected to communication channel impairments, bandwidth constraint is an important challenge in data transmission. That issue is addressed mainly by source and channel coding techniques aiming at an effective transmission. This paper targets a significant further bandwidth reduction by proposing an on-the-fly analysis on the satellite to decide which information is effectively useful before coding and transmitting. The images are tiled and classified using a set of detection algorithms after defining the least relevant content for general remote sensing applications. The methodology makes use of the red-band, green-band, blue-band, and near-infrared-band measurements to perform the classification of the content by managing a cloud detection algorithm, a change detection algorithm, and a vessel detection algorithm. Experiments for a set of typical scenarios of summer and winter days in Stockholm, Sweden, were conducted, and the results show that non-important content can be identified and discarded without compromising the predefined useful information for water and dry-land regions. For the evaluated images, only 22.3% of the information would need to be transmitted to the ground station to ensure the acquisition of all the important content, which illustrates the merits of the proposed method. Furthermore, the embedded platform's constraints regarding processing time were analyzed by running the detection algorithms on Unibap's iX10-100 space cloud platform.

Taxonomy and Phylogeny of Peniophora Sensu Lato (Russulales, Basidiomycota).

Peniophora is an old corticioid genus, from which two small satellite genera, Dendrophora and Duportella, were derived based on morphological differences. Molecular systematic studies showed that they belong to Peniophoraceae, Russulales, but the inter- and intra-generic phylogenetic relationships are still unclear. Moreover, the species diversity of this group in subtropical and tropical Asia has not been sufficiently investigated and studied. In this study, we carried out an intensive taxonomic and phylogenetic study on Peniophora sensu lato based on analyses of concatenated ITS1-5.8S-ITS2 (ITS, Internal Transcribed Spacer) and 28S (D1-D2 domains of nuc 28S rDNA) sequence data of all available species worldwide. In the phylogenetic trees, species of Peniophora s. l. (sensu lato) including types of Peniophora s.s. (sensu stricto), Dendrophora and Duportella were interspersed within a strongly supported clade. It means that the morphological delimitations of the three genera are not reliable, and they should be regarded as a large genus. As a result, eight species of Duportella were transferred to Peniophora, although five of them have not been sequenced. Four new distinct lineages, corresponding to Peniophora cremicolor, P. major, P. shenghuae and P. vietnamensis spp. nov., were recovered in the trees. Peniophora taiwanensis is treated as a later synonym of P. malaiensis based on morphological and molecular evidence. Duportella renispora is excluded from Peniophoraceae, because BLAST results of the ITS and 28S sequences of the holotype showed that it is closely related to Amylostereum. Descriptions and illustrations are provided for the four new species, and an identification key is given for all 25 species of Peniophora in China. Our results indicated that the species diversity of the corticioid fungi in Asia is rich and deserves further study.

Additive manufacturing and metallization of high-frequency communication devices

Additive manufacturing (AM) can be applied to new scenarios where traditional subtractive techniques limit geometry and assembling freedom. One of these scenarios is the development of high-frequency devices for communication systems, where AM offers the capability to develop high-complexity geometries, reducing the devices’ weight and cost. This is extraordinarily convenient for recent small satellites where size, weight, and integration are vital. This work presents an AM process specially optimized to develop communication devices. Industry needs have been studied, and materials and manufacturing techniques have been chosen accordingly. Two communication devices, a band-pass filter and a horn antenna, have been developed using two VAT photopolymerization (VPP) processes and different resins. Printed devices were metallized using a two-step process based on a first electroless metallisation and a final galvanic plating. The manufactured pieces were sandblasted prior to metallization to increase plating adhesion and reduce surface roughness. Finally, several dimensional analyses were performed to evaluate the effect of finishing and plating on the manufacturing process using scanning electron microscopy, profilometry, and contact metrology. The electromagnetic response of developed devices is excellent and comparable with commercial devices manufactured with subtractive techniques. A preliminary tolerance analysis was carried out to approximate the systematic deviation of the overall manufacturing process, considering the erosion of sandblasting and the thickness of copper plating. These deviations were compensated in the design step to improve the dimensional accuracy of the band-pass filter.

Satellite Swarm-Based Antenna Arrays for 6G Direct-to-Cell Connectivity

Direct connectivity in L/S frequency bands between satellites and common mobile terrestrial user equipment (UE), such as smartphones, is an essential feature for future 6G non-terrestrial networks. The technical trend in closing the link between the communication endpoints is to develop large phased antenna arrays to be launched in LEO orbit. Satellite swarms represent an innovative and promising approach. Swarms are composed of several small and lightweight satellites organized in a free-flying formation (i.e., wireless connected) or a tethered formation (i.e., wired connected) creating a distributed phased antenna array. It has the potential to provide an enhanced gain, narrower beam width and lower launch/build costs compared to conventional single satellite systems with large phased antenna arrays. The first objective of this work is the design of swarm-based antenna arrays, in which the impact of key parameters such as the number of satellites in the swarm, their reciprocal distance and the array geometry, is thoroughly analyzed. It is shown that the undesired phenomenon of grating lobes can be mitigated via optimized array geometries and a new geometry named the enhanced logarithmic spiral array (ELSA) is presented. The second objective of this work is the identification of the most important research directions and system design aspects for the swarm system. In particular, it is shown that tethered swarms with ELSA geometries, innovative deployable structures and very small satellites can foster the deployment of swarms in future satellite systems.

A STUDY ON THE RECENT ADVANCES IN THE DESIGN OF MEMS-BASED SOLID MICROTHRUSTERS

In the past few decades, space technology has moved toward using many small satellites working in a cluster instead of making individual satellites for space missions. Nano or microsatellites increase the reliability of the mission while minimizing cost, rather than having one large satellite increasing both the cost and the failure risk for any given space mission. Considering the case of a small satellite cluster, it is easy to manage mission requirements with less complexity during any hazard, compared to an individual satellite. All of this has led to the increasing application of micro and nanosatellites in space engineering. These small satellites are propelled by micropropulsion created by microthrusters. Currently, liquid, gas, and electrical thrusters are the most common. This paper mainly describes the recent advancements in the field of MEMS microthrusters. MEMS (microelectromechanical system) thrusters are used in small satellites in a variety of ways that require very little thrust. In the paper discussion, MEMS-based solid-propellant microthrusters (SPMs) are delineated. All advancements in the MEMS solid thrusters are indicated in the article, dedicated to mounting schemes, designing approaches, and various performance testing experiments. The main challenge in this technology is combustion, which takes place in an exceptionally small volume.

Achievable parameters of the X-band synthetic aperture radar based on small satellite

Space-based synthetic aperture radar systems are actively used for remote sensing of the Earth and have significant capabilities. Advances in microelectronics have made it possible to create and launch into orbit compact radars based on small satellites. Analysis of the capabilities of such radars is an actual problem. In this paper the issues of simulation and estimation of the antenna area, noise equivalent sigma zero, spatial and radiometric resolution of space-based synthetic aperture radars (SAR) operating on the basis of small spacecraft are considered. The necessary mathematical apparatus is given and the above values are calculated for the X-band SAR operating in strip mode at maximum resolution. The influence of the main technical parameters of space SAR on dimensions of antenna, on sensitivity, spatial and radiometric resolution is analyzed.

Formation-of-Arrays Antenna Technology for High-Throughput Mobile Non-Terrestrial Networks

Effective integration of terrestrial and non-terrestrial segments is one of the key research avenues in the design of current and future wireless communication networks. To this aim, modern communication-satellite constellations intend to attain sufficiently high throughput in terms of bit rate per unit area on the ground by rather aggressive patterns of spatial frequency reuse. This goal calls for on-board narrow-beam antennas, whose size turns out to be in many cases incompatible with the size/mass and accommodation constraints of the hosting satellite. This paper investigates the attainable performance of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">large distributed arrays of antennas</i> implemented as the ensemble of a few to many simpler sub-antennas of smaller sizes, carried by one (small) satellite each. The sub-antennas can in their turn be implemented like (regular) 2D arrays of simple radiating elements, realizing an overall (distributed) antenna architecture that we call “formation of arrays” (FoA). The satellites that implement this radiating architecture need to be relatively close to each other and constitute a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">formation</i> of flying objects, to be coordinated and controlled as a whole. In this paper, we develop a theoretical analysis of an FoA antenna, and we show how to take advantage of this new technology to improve network throughput in a multi-beam S-band mobile communication network with low-earth or geostationary orbiting satellites directly providing 5G-like communication services to hand-held user terminals.

Feasibility assessment of a small Earth observation satellite mission propelled with hydrogen peroxide system on a very low Earth orbit

Feasibility assessment of a small Earth observation satellite mission propelled with hydrogen peroxide system on a very low Earth orbit

Nanosatellite Temperature &amp; HumiditySensor

In this paper, the development of nanosatellite temperature &amp; humidity sensor is presented. Nanotechnology has emerged as a significant field of science and engineering with potential applications across multiple fields, including medicine, electronics, and energy. By studying materials at the nanoscale level, researchers have discovered unique properties that can be harnessed for innovative solutions to real-world problems. Nanotechnology is an area of ongoing research and development with efforts to explore its possibilities and challenges. This paper provides an overview of nanotechnology and its applications, with a particular focus on its use in space exploration. Over the past two decades, the rise of "New Space" has democratized access to space, allowing for the development of small and cost-effective satellites known as nanosatellites or CubeSats. These nanosatellites have revolutionized space exploration, enabling new approaches to space missions and facilitating creative solutions to space-related challenges. Nanosatellites have demonstrated their potential for Earth observation, climate monitoring, scientific research, and commercial applications such as space-based logistics and internet coverage. By using sensors, nanosatellites can collect valuable data and monitor their environments, making them an effective tool for space exploration and research. The work done &amp; presented in this paper is the result of the mini-project work that has been done by the first sem engineering students of the college and as such there is little novelty in it and the references are being taken from various sources from the internet, the paper is being written by the students to test their writing skills in the starting of their engineering career and also to test the presentation skills during their mini-project presentation. The work done &amp; presented in this paper is the report of the assignment / alternate assessment tool as a part and parcel of the academic assignment of the first year subject on nanotechnology &amp; IoT.

SWRNet: A Deep Learning Approach for Small Surface Water Area Recognition Onboard Satellite

SWRNet: A Deep Learning Approach for Small Surface Water Area Recognition Onboard Satellite

Low Altitude Satellite Constellation for Futuristic Aerial-Ground Communications

This paper discusses the significance and prospects of low altitude small satellite aerial vehicles to ensure smooth aerial-ground communications for next-generation broadband networks. To achieve the generic goals of fifthgeneration and beyond wireless networks, the existing aerial network architecture needs to be revisited. The detailed architecture of low altitude aerial networks and the challenges in resource management have been illustrated in this paper. Moreover, we have studied the coordination between promising communication technologies and low altitude aerial networks to provide robust network coverage. We talk about the techniques that can ensure userfriendly control and monitoring of the low altitude aerial networks to bring forth wireless broadband connectivity to a new dimension. In the end, we highlight the future research directions of aerial-ground communications in terms of access technologies, machine learning, compressed sensing, and quantum communications.

Cooperative Angles-Only Relative Navigation Algorithm for Multi-Spacecraft Formation in Close-Range

As to solve the collaborative relative navigation problem for near-circular orbiting small satellites in close-range under GNSS denied environment, a novel consensus constrained relative navigation algorithm based on the lever arm effect of the sensor offset from the spacecraft center of mass is proposed. Firstly, the orbital propagation model for the relative motion of multi-spacecraft is established based on Hill-Clohessy-Wiltshire dynamics and the line-of-sight measurement under sensor offset condition is modeled in Local Vertical Local Horizontal frame. Secondly, the consensus constraint model for the relative orbit state is constructed by introducing the geometry constraint between the spacecraft, based on which the consensus unscented Kalman filter is designed. Thirdly, the observability analysis is done and the necessary conditions of the sensor offset to make the state observable are obtained. Lastly, digital simulations are conducted to verify the proposed algorithm, where the comparison to the unconstrained case is also done. The results show that the estimated error of the relative position converges very quickly, the location error is smaller than 10 m under the condition of 10−3 rad level camera and 5 m offset.

A core-satellite micellar system against primary tumors and their lymphatic metastasis through modulation of fatty acid metabolism blockade and tumor-associated macrophages.

Lymph nodes (LNs) are the initial sanctuary of various metastatic tumor cells, and thus a precise lymphatic drug delivery strategy is necessary for the effective inhibition of metastasis. However, the complex biological barriers have restrained the drug delivery to tumor-draining lymph nodes (TDLNs). Metastatic tumor cells would undergo metabolic adaptation towards fatty acid oxidation (FAO) upon reaching the lipid-rich LNs. Herein, to inhibit primary tumors and their lymphatic metastasis, a core-satellite matrix metalloproteinase 2 (MMP-2) responsive micellar system was developed for sequential delivery of paclitaxel (PTX) and the metabolism-regulating drug etomoxir (ET) to tumors and TDLNs, respectively. Upon arrival at the tumor microenvironment (TME), the small satellite micelle encapsulating ET was detached from the core micelle in response to MMP-2, which not only drained to TDLNs via tumor-draining lymphatic vessels and inhibited the FAO of metastatic tumor cells, but also blocked M2-like macrophage polarization in the TME. Meanwhile, the core micelle containing PTX could largely accumulate in the TME and kill tumor cells. In an orthotopic 4T1 breast cancer model, the tumor and TDLN dual-targeted core-satellite micellar system effectively inhibited the growth of the primary tumor and alleviated immune suppression by blocking macrophage polarization. More importantly, tumor lymphatic metastasis was suppressed through FAO metabolic regulation. This strategy provides a promising approach for TDLN targeted therapy against breast cancer and its lymphatic metastasis.

Assessing the Relative Performance of GNSS-R Flood Extent Observations: Case Study in South Sudan

Flooding is one of the deadliest and costliest natural disasters. Climate change-induced flooding events are increasing worldwide, disproportionately impacting low-income and developing communities. While early warning systems save lives, satellite-based observation systems are vital for the disaster relief and recovery phases. Current satellite-based operational flood products are largely based on either optical remote-sensing methods, which exhibit a limited ability to detect water through clouds and vegetation, or microwave remote sensing, which provides relatively low spatial and temporal resolution. New small satellite constellations using radar or GNSS reflectometry (GNSS-R) have been shown to enhance our ability to overcome these deficiencies. In this work, we quantify the performance of using GNSS-R measurements from the NASA Cyclone Global Navigation Satellite Systems (CYGNSS) satellite constellation to map surface water in South Sudan and the Sudd wetland in comparison with a set of representative operational products. We make quantitative comparisons of our results with operational flood products based on Visible Infrared Imaging Radiometer Suite (VIIRS) and MODIS and with C-band Sentinel-1 synthetic aperture radar. We find that our method detects 35.4% more surface water than Sentinel-1, while the VIIRS- and MODIS-based products underestimate by 4.8% and 83.7%, respectively. We use several metrics commonly used to evaluate classification performance: precision, true positive rate (TPR), true negative rate (TNR), F2-score, and the Matthews correlation coefficient (MCC) and assess the comparisons in this statistical framework. We discuss the consequences of our findings, including ways CYGNSS data may enhance current flood products and assist decision-makers and emergency managers.

Embracing Small Satellites Into Future 6G Inclusive IoT Coverage: A Deployment of Diversity-Based Theoretical Framework

Embracing Small Satellites Into Future 6G Inclusive IoT Coverage: A Deployment of Diversity-Based Theoretical Framework

Analog Maximum Peak Power Tracking Techniques for Small Satellites

This work describes the implementation of three Maximum Peak Power Tracking methods devised for small satellites. The three methods are the Analog oscillating Maximum Power Point Tracking, the Analog Global Maximum Peak Power Tracking and the Analog Global Maximum Output Power Tracking. An interplanetary mission (Mars-Asteroid belt) with complex power-voltage solar array characteristics, including several local maximum power points, is considered to evaluate each peak power tracking technique. The three peak power tracking techniques have been integrated in an unregulated battery bus topology using synchronous buck converters as solar array regulators. High reliability design is achieved using analog electronic parts with space-qualified counterparts. Each peak power tracking method has been optimized individually for the best performance and then compared with the others. The experimental validation suggests that the preferred method strongly depends on the expected power-voltage solar array characteristics and mission parameters.

Comparative analysis of problem of thermal shock of elastic elements of small satellite in one-dimensional and two-dimensional formulations

The article demonstrates a comparative analysis of one-dimensional and two-dimensional problems of thermoelectricity for thermal shock of a plate. Similar resolutions of a one-dimensional problem in the framework of a two-dimensional problem are identified. Recommendations for such resolutions are given. The results of the research can be used in modeling the thermal shock of the elastic elements of a small satellite.

Mock HI-galaxy catalogs and HI mass functions for future large-scale surveys

One of the interesting modern astrophysics topics is the discrepancy in HI-galaxy number density between the standard model ΛCDM prediction and observations, e.g., ALFALFA and HIPASS. Since then, the simulation over-predicted the abundance and HI mass (MHI) of small satellite and low-mass galaxies. Both problems still require sensitive instruments for wider and deeper HI surveys to increase the number of low-mass HI-galaxy samples. Current HI-galaxy surveys can only reach down to ∼ 107 Solar mass (M⊙). The sensitivity of upcoming radio surveys such as FAST or ASKAP are expected to reach lower MHI and higher redshift(z) HI-galaxy data. Alternatively, the HI source catalogs from cosmological simulations are used to determine the expected HIMF with the upcoming HI survey specification. This work aims to compare the HIMF in various HI conversion recipes. Various HIMF were determined by using the Multidark(Planck) catalog with the box (MB) and the light-cone (ML) types, and were parameterized by the Schechter function. In comparison to the Schechter function, we discovered that the HIMF from cold gas mass (Mcold) conversion method begins to diverge on MHI ≲ 108.5 M⊙. The HIMF from halo mass (Mhalo) recipe, which was constrained by the optical counterpart galaxy clustering, provided a satisfactory relevant shape of HIMF. The best-fit parameter α of MB and ML are equal to 0.00 ± 0.010 and −0.02 ± 0.0026, respectively. The flatter α values from simulations could indicate that the number density of low-MHI is underestimated.