Applied Sciences

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16 pages, 4849 KiB

Open AccessArticle

On-Orbit Magnetometer Data Calibration Using Genetic Algorithm and Interchangeability of the Calibration Parameters

by Dulani Chamika Withanage, Mariko Teramoto and Mengu Cho

Appl. Sci. 2023, 13(11), 6742; https://doi.org/10.3390/app13116742 - 1 Jun 2023

Cited by 2 | Viewed by 1638

Magnetometers are important sensors with applications in the attitude determination and control systems of satellites. CubeSats have certain limitations related to power, mass, and volume. Due to this, CubeSat magnetometers are not separated from other electrical circuits inside the satellite. Thus, it is [...] Read more.

Magnetometers are important sensors with applications in the attitude determination and control systems of satellites. CubeSats have certain limitations related to power, mass, and volume. Due to this, CubeSat magnetometers are not separated from other electrical circuits inside the satellite. Thus, it is important to calibrate the magnetometer, simulating operating conditions while the satellite is running before the launch. However, due to the limited facilities, not every CubeSat is able to calibrate its magnetometers properly on the ground. This study focuses on the calibration of on-orbit magnetometer data observed by BIRDS-3 CubeSats with a genetic algorithm. High oscillations in the total magnetic field were found in the on-orbit magnetic field data measured by magnetometers inside BIRDS-3 CubeSats. Nine unknowns, scaling factors, non-orthogonal angles, and offsets are identified with the genetic algorithm. This paper discusses the factors that affect the high oscillations in the measured total magnetic field data. For the calibration, we used magnetic field data similar to those of a model magnetic field, as the deviation is smaller. This paper presents the accuracy of determining unknowns using the genetic algorithm, as well as the interchangeability of the answers with additional orbit data from the same satellite. This method can be used in the future to calibrate magnetometers inside CubeSats before or after launch. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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26 pages, 5244 KiB

Open AccessArticle

Closed-Form Method for Atmospheric Correction (CMAC) of Smallsat Data Using Scene Statistics

by David P. Groeneveld, Timothy A. Ruggles and Bo-Cai Gao

Appl. Sci. 2023, 13(10), 6352; https://doi.org/10.3390/app13106352 - 22 May 2023

Cited by 3 | Viewed by 1653

Abstract

High-cadence Earth observation smallsat images offer potential for near real-time global reconnaissance of all sunlit cloud-free locations. However, these data must be corrected to remove light-transmission effects from variable atmospheric aerosol that degrade image interpretability. Although existing methods may work, they require ancillary [...] Read more.

High-cadence Earth observation smallsat images offer potential for near real-time global reconnaissance of all sunlit cloud-free locations. However, these data must be corrected to remove light-transmission effects from variable atmospheric aerosol that degrade image interpretability. Although existing methods may work, they require ancillary data that delays image output, impacting their most valuable applications: intelligence, surveillance, and reconnaissance. Closed-form Method for Atmospheric Correction (CMAC) is based on observed atmospheric effects that brighten dark reflectance while darkening bright reflectance. Using only scene statistics in near real-time, CMAC first maps atmospheric effects across each image, then uses the resulting grayscale to reverse the effects to deliver spatially correct surface reflectance for each pixel. CMAC was developed using the European Space Agency’s Sentinel-2 imagery. After a rapid calibration that customizes the method for each imaging optical smallsat, CMAC can be applied to atmospherically correct visible through near-infrared bands. To assess CMAC functionality against user-applied state-of-the-art software, Sen2Cor, extensive tests were made of atmospheric correction performance across dark to bright reflectance under a wide range of atmospheric aerosol on multiple images in seven locations. CMAC corrected images faster, with greater accuracy and precision over a range of atmospheric effects more than twice that of Sen2Cor. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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30 pages, 4727 KiB

Open AccessArticle

Elevation Angle Characterization for LEO Satellites: First and Second Order Statistics

by Juan Misael Gongora-Torres, Cesar Vargas-Rosales, Alejandro Aragón-Zavala and Rafaela Villalpando-Hernandez

Appl. Sci. 2023, 13(7), 4405; https://doi.org/10.3390/app13074405 - 30 Mar 2023

Cited by 3 | Viewed by 7474

Abstract

The elevation angle

θ

is relevant for the Low Earth orbit (LEO) satellite communications since it is always changing its relative position with respect to fixed Earth stations (ES’s), and this affects the link length and received power,

P_{R}

. This article [...] Read more.

The elevation angle

θ

is relevant for the Low Earth orbit (LEO) satellite communications since it is always changing its relative position with respect to fixed Earth stations (ES’s), and this affects the link length and received power,

P_{R}

. This article provides a new methodology to compute the probability density function (PDF) and cumulative distribution function (CDF) of the elevation angle,

θ

, for diverse ES locations. This methodology requires as input parameters an ES latitude,

ϕ

, an orbit inclination value, i, and an orbit altitude, h. The elevation angle is characterized through a well known random variable, which facilitates the computation of the first and second-order statistics, and helps to determine the expected value and measures of dispersion of the angle

θ

for a particular ES location. The proposed methodology allows an easy and quick calculation of the elevation angle’s CDF, facilitating comparisons against CDF’s of more ES’s located at different latitudes, and longitudes,

λ

; as well as the comparisons of CDF’s of the elevation angle produced by different orbits. Extensive simulation results are summarized in a small table, which allows computation of the elevation angle’s CDF and PDF for multiple ES locations without requiring of simulations and statistical fitting. Finally, the proposed methodology is validated through an extensive error analysis that show the suitability of the obtained results to characterize the elevation angle. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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27 pages, 12170 KiB

Open AccessArticle

Design and Validation of a U-Net-Based Algorithm for Star Sensor Image Segmentation

by Marco Mastrofini, Ivan Agostinelli and Fabio Curti

Appl. Sci. 2023, 13(3), 1947; https://doi.org/10.3390/app13031947 - 2 Feb 2023

Cited by 7 | Viewed by 2335

Abstract

The present work focuses on the investigation of an artificial intelligence (AI) algorithm for brightest objects segmentation in night sky images’ field of view (FOV). This task is mandatory for many applications that want to focus on the brightest objects in an optical [...] Read more.

The present work focuses on the investigation of an artificial intelligence (AI) algorithm for brightest objects segmentation in night sky images’ field of view (FOV). This task is mandatory for many applications that want to focus on the brightest objects in an optical sensor image with a particular shape: point-like or streak. The algorithm is developed as a dedicated application for star sensors both for attitude determination (AD) and onboard space surveillance and tracking (SST) tasks. Indeed, in the former, the brightest objects of most concern are stars, while in the latter they are resident space objects (RSOs). Focusing attention on these shapes, an AI-based segmentation approach can be investigated. This will be carried out by designing, developing and testing a convolutional neural network (CNN)-based algorithm. In particular, a U-Net will be used to tackle this problem. A dataset for the design process of the algorithm, network training and tests is created using both real and simulated images. In the end, comparison with traditional segmentation algorithms will be performed, and results will be presented and discussed together with the proposal of an electro-optical payload for a small satellite for an in-orbit validation (IOV) mission. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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25 pages, 6243 KiB

Open AccessArticle

Modelling the Stages of Pre-Project Preparation and Design Development in the Life-Cycle of an Investment and Construction Project

by Azariy Lapidus, Dmitriy Topchiy, Tatyana Kuzmina and Polina Bolshakova

Appl. Sci. 2022, 12(23), 12401; https://doi.org/10.3390/app122312401 - 4 Dec 2022

Cited by 3 | Viewed by 3110

Abstract

The stages of pre-project preparation and design development are the fundamentals to the further implementation of an investment and construction project. The success of construction and commissioning of facilities depends on the smooth completion of these stages. The duration of stages depends on [...] Read more.

The stages of pre-project preparation and design development are the fundamentals to the further implementation of an investment and construction project. The success of construction and commissioning of facilities depends on the smooth completion of these stages. The duration of stages depends on the competence and coordination of interaction between participants of an investment and construction project, rational decision making by the project manager and a number of other factors. Identifying these factors and finding rational planning options in terms of the stages of pre-project preparation and design development is a highly relevant task. With this in mind, the authors have developed an organizational and management model of a rational procedure to be implemented by the project manager at the stages of pre-project preparation and design development for a facility to be constructed. The model takes into account the influence of negative factors. The authors have also developed a method for selecting rational solutions at the stages in question. The analysis of the research literature and regulatory documents was performed for this purpose. The method of expert evaluations, elements of numerical analysis, mathematical processing of practical results and methods of mathematical modeling were applied. As a result, the authors have developed an organizational and management model for a rational combination of procedures at the stages of pre-project preparation and design development for a facility to be constructed and derived a formula determining the duration of implementation of each stage and a technique designated for selecting rational solutions at the stages in question. The findings of this study can simplify project planning and process management at the stages of pre-project preparation and design development in terms of information modeling. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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24 pages, 1403 KiB

Open AccessArticle

The AlfaCrux CubeSat Mission Description and Early Results

by Renato Alves Borges, Andrea Cristina dos Santos, William Reis Silva, Leonardo Aguayo, Geovany Araújo Borges, Marcelo Monte Karam, Rogério Baptista de Sousa, Bibiano Fernández-Arruti García, Vitor Manuel de Sousa Botelho, José Manuel Fernández-Carrillo, José Miguel Lago Agra, Fernando Aguado Agelet, João Vítor Quintiliano Silvério Borges, Alexandre Crepory Abbott de Oliveira, Bruno Tunes de Mello, Yasmin da Costa Ferreira Avelino, Vinícius Fraga Modesto and Emanuel Couto Brenag

Appl. Sci. 2022, 12(19), 9764; https://doi.org/10.3390/app12199764 - 28 Sep 2022

Cited by 3 | Viewed by 3144

Abstract

On 1 April 2022, the AlfaCrux CubeSat was launched by the Falcon 9 Transporter-4 mission, the fourth SpaceX dedicated smallsat rideshare program mission, from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida into a Sun-synchronous orbit at 500 km. [...] Read more.

On 1 April 2022, the AlfaCrux CubeSat was launched by the Falcon 9 Transporter-4 mission, the fourth SpaceX dedicated smallsat rideshare program mission, from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida into a Sun-synchronous orbit at 500 km. AlfaCrux is an amateur radio and educational mission to provide learning and scientific benefits in the context of small satellite missions. It is an opportunity for theoretical and practical learning about the technical management, systems design, communication, orbital mechanics, development, integration, and operation of small satellites. The AlfaCrux payload, a software-defined radio hardware, is responsible for two main services, which are a digital packet repeater and a store-and-forward system. In the ground segment, a cloud-computing-based command and control station has been developed, together with an open access online platform to access and visualize the main information of the AlfaCrux telemetry and user data and experiments. It also becomes an in-orbit database reference to be used for different studies concerned with, for instance, radio propagation, attitude reconstruction, data-driven calibration algorithms for satellite sensors, among others. In this context, this paper describes the AlfaCrux mission, its main subsystems, and the achievements obtained in the early orbit phase. Scientific and engineering assessments conducted with the spacecraft operations to tackle unexpected behaviors in the ground station and also to better understand the space environment are also presented and discussed. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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10 pages, 359 KiB

Open AccessArticle

An Iterative Guidance and Navigation Algorithm for Orbit Rendezvous of Cooperating CubeSats

by Simone Battistini, Giulio De Angelis, Mauro Pontani and Filippo Graziani

Appl. Sci. 2022, 12(18), 9250; https://doi.org/10.3390/app12189250 - 15 Sep 2022

Cited by 2 | Viewed by 1970

Abstract

Modern space missions often require satellites to perform guidance, navigation, and control tasks autonomously. Despite their limited resources, small satellites are also involved in this trend, as in-orbit rendezvous and docking maneuvers and formation flying have become common requirements in their operational scenarios. [...] Read more.

Modern space missions often require satellites to perform guidance, navigation, and control tasks autonomously. Despite their limited resources, small satellites are also involved in this trend, as in-orbit rendezvous and docking maneuvers and formation flying have become common requirements in their operational scenarios. A critical aspect of these tasks is that these algorithms are very much intertwined with each other, although they are often designed completely independently of one another. This paper describes the design and simulation of a guidance and relative navigation architecture for the rendezvous of two cooperating CubeSats. The integration of the two algorithms provides robustness to the solution, by simulating realistic levels of noise and uncertainty in the guidance law implementation. The proposed guidance law is derived based on the linearized equations of orbital motion, written in terms of spherical coordinates. The trajectory is iteratively corrected at a fixed time step, so that errors from the navigation and the initial orbital condition can be recovered. The navigation algorithm processes the bearing and range measurements from a camera and an intersatellite link through an unscented filter to provide the information required from the guidance law. A Monte Carlo campaign based on a 3-DOF simulation demonstrates the effectiveness of the proposed solution. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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21 pages, 5487 KiB

Open AccessArticle

Development of Innovative CubeSat Platform for Mass Production

by Eyoas Ergetu Areda, Jose Rodrigo Cordova-Alarcon, Hirokazu Masui and Mengu Cho

Appl. Sci. 2022, 12(18), 9087; https://doi.org/10.3390/app12189087 - 9 Sep 2022

Cited by 6 | Viewed by 3288

Abstract

With the recent increase in CubeSats’ ability to undertake complex and advanced missions, they are being considered for missions such as constellations, which demand high development efficiency. From a satellite interface perspective, productivity can be maximized by implementing a flexible modular structural platform [...] Read more.

With the recent increase in CubeSats’ ability to undertake complex and advanced missions, they are being considered for missions such as constellations, which demand high development efficiency. From a satellite interface perspective, productivity can be maximized by implementing a flexible modular structural platform that promotes easy reconfigurability during the integration and testing phase. Thus, the structural design of a CubeSat plays a crucial role in facilitating the satellite integration process. In most cases, the mechanical interface implemented between the primary load-supporting structure and internal satellite subassemblies affects the speed and efficiency of satellite integration by adding or reducing complexity. Most CubeSat structural designs use stacking techniques to mount PCBs onto the primary structure using stacking rods/screws. As a result, the internal subsystems are interconnected. This conventional interface method is observed to increase the number of structural parts, while increasing complexity during integration. In this study, flexible 3U and 1U CubeSat platforms are developed, based on the slot concept. This innovative mounting design provides a simple method of mounting PCBs into the slots. The concept is evaluated and verified for its feasibility for mass production applications. Count and complexity analysis is carried to evaluate the proposed design against the conventional type of structural interface methods. The assessment reveals that this new concept demonstrates a significant improvement in the efficiency of the mass production process. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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24 pages, 7476 KiB

Open AccessArticle

Scalable and Configurable Electrical Interface Board for Bus System Development of Different CubeSat Platforms

by Marloun Sejera, Takashi Yamauchi, Necmi Cihan Orger, Yukihisa Otani and Mengu Cho

Appl. Sci. 2022, 12(18), 8964; https://doi.org/10.3390/app12188964 - 6 Sep 2022

Cited by 3 | Viewed by 2398

Abstract

A flight-proven electrical bus system for the 1U CubeSat platform was designed in the BIRDS satellite program at the Kyushu Institute of Technology. The bus utilizes a backplane board as the mechanical and electrical interface between the subsystems and the payloads. The electrical [...] Read more.

A flight-proven electrical bus system for the 1U CubeSat platform was designed in the BIRDS satellite program at the Kyushu Institute of Technology. The bus utilizes a backplane board as the mechanical and electrical interface between the subsystems and the payloads. The electrical routes on the backplane are configured by software using a complex programmable logic device (CPLD). It allows for reusability in multiple CubeSat projects while lowering costs and development time; as a result, resources can be directed toward developing the mission payloads. Lastly, it provides more time for integration and system-level verification, which are critical for a reliable and successful mission. The current trend of CubeSat launches is focused on 3U and 6U platforms due to their capability to accommodate multiple and complex payloads. Hence, a demonstration of the electrical bus system to adapt to larger platforms is necessary. This study demonstrates the configurable electrical interface board’s scalability in two cases: the capability to accommodate (1) multiple missions and (2) complex payload requirements. In the first case, a 3U-size configurable backplane prototype was designed to handle 13 mission payloads. Four CPLDs were used to manage the limited number of digital interfaces between the existing bus system and the mission payloads. The measured transmission delay was up to 20 ns, which is acceptable for simple serial communications such as UART and SPI. Furthermore, the measured energy consumption of the backplane per ISS orbit was only 28 mWh. Lastly, the designed backplane was proven to be highly reliable as no bit errors were detected throughout the functionality tests. In the second case, a configurable backplane was implemented in a 6U CubeSat with complex payload requirements compared to the 1U CubeSat platform. The CubeSat was deployed in ISS orbit, and the initial on-orbit results indicated that the designed backplane supported missions without issues. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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17 pages, 3877 KiB

Open AccessArticle

Performance Evaluation of Machine Learning Methods for Anomaly Detection in CubeSat Solar Panels

by Adolfo Javier Jara Cespedes, Bramandika Holy Bagas Pangestu, Akitoshi Hanazawa and Mengu Cho

Appl. Sci. 2022, 12(17), 8634; https://doi.org/10.3390/app12178634 - 29 Aug 2022

Cited by 5 | Viewed by 3034

Abstract

CubeSat requirements in terms of size, weight, and power restrict the possibility of having redundant systems. Consequently, telemetry data are the primary way to verify the status of the satellites in operation. The monitoring and interpretation of telemetry parameters relies on the operator’s [...] Read more.

CubeSat requirements in terms of size, weight, and power restrict the possibility of having redundant systems. Consequently, telemetry data are the primary way to verify the status of the satellites in operation. The monitoring and interpretation of telemetry parameters relies on the operator’s experience. Therefore, telemetry data analysis is less reliable, considering the data’s complexity. This paper presents a Machine Learning (ML) approach to detecting anomalies in solar panel systems. The main challenge inherited from CubeSat is its capability to perform onboard inference of the ML model. Nowadays, several simple yet powerful ML algorithms for performing anomaly detection are available. This study investigates five ML algorithm candidates, considering classification score, execution time, model size, and power consumption in a constrained computational environment. The pre-processing stage introduces the windowed averaging technique besides standardization and principal component analysis. Furthermore, the paper features the background, bus system, and initial operational data of BIRDS-4, a constellation made of three 1U CubeSats released from the International Space Station in March 2021, with a ML model proposal for future satellite missions. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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26 pages, 7686 KiB

Open AccessArticle

Assessing the Capacity and Coverage of Satellite IoT for Developing Countries Using a CubeSat

by Pooja Lepcha, Tharindu Dayarathna Malmadayalage, Necmi Cihan Örger, Mark Angelo Purio, Fatima Duran, Makiko Kishimoto, Hoda Awny El-Megharbel and Mengu Cho

Appl. Sci. 2022, 12(17), 8623; https://doi.org/10.3390/app12178623 - 28 Aug 2022

Cited by 11 | Viewed by 4263

Abstract

Many regions in developing countries do not have any access to communication networks even though the number of devices connected through the Internet of Things (IoT) is increasing significantly. A small satellite platform could provide global network coverage in low Earth orbit to [...] Read more.

Many regions in developing countries do not have any access to communication networks even though the number of devices connected through the Internet of Things (IoT) is increasing significantly. A small satellite platform could provide global network coverage in low Earth orbit to these remote locations at a low cost. This paper describes the overall mission architecture and the implementation of remote IoT using a 1U volume in 6U CubeSat platform named KITSUNE. In KITSUNE, one of the missions is to leverage IoT for building a network of remote ground sensor terminals (GST) in 11 mostly developing countries. This paper evaluates the capacity and coverage of a satellite-based IoT network for providing remote data-collection services to these countries. The amount of data that could be collected from the GSTs and forwarded accurately to the users determines the actual capacity of the Store and Forward (S&F) mission. Therefore, there are several proposed parameters to estimate this capacity in this study. In addition, these parameters are retrieved from the simulations, ground test results, and on-orbit observations with the KITSUNE satellite. The proposed IoT system, which is composed of the GSTs and IoT subsystem onboard KITSUNE satellite, is determined to be capable of providing valuable information from remote locations. In addition, the collected data are achieved and analyzed to monitor sensory data specific to each country, and it could help to generate prediction profiles as well. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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19 pages, 714 KiB

Open AccessFeature PaperArticle

Analytic Derivation of Ascent Trajectories and Performance of Launch Vehicles

by Paolo Teofilatto, Stefano Carletta and Mauro Pontani

Appl. Sci. 2022, 12(11), 5685; https://doi.org/10.3390/app12115685 - 3 Jun 2022

Cited by 6 | Viewed by 2356

Abstract

This papers introduces an analytic method to define multistage launcher trajectories to determine the payload mass that can be inserted in orbits of different semimajor axes and inclinations. This method can evaluate the gravity loss, which is the main term to be subtracted [...] Read more.

This papers introduces an analytic method to define multistage launcher trajectories to determine the payload mass that can be inserted in orbits of different semimajor axes and inclinations. This method can evaluate the gravity loss, which is the main term to be subtracted to the Tziolkowski evaluation of the velocity provided by the thrust of a launcher. In the method, the trajectories are dependent on two parameters only: the final flight-path angle

γ_{f}

at the end of the gravity-turn arc of the launcher trajectory and the duration

t_{c}

of the coasting arc following the gravity-turn phase. The analytic formulas for the gravity-turn phase, being solutions of differential equations with a singularity, allow us to identify the trajectory with a required final flight-path angle

γ_{f}

in infinite solutions with the same initial vertical launch condition. This can also drive the selection of the parameters of the pitch manoeuvre needed to turn the launcher from the initial vertical arc. For any pair

γ_{f}

and

t_{c}

, a launcher trajectory is determined. A numerical solver is used to identify the values

γ_{f}

and

t_{c}

, allowing for the insertion of the payload mass into the required orbit. The analytic method is compared with a numerical code including the drag effect, which is the only effect overlooked in the analytic formulas. The analytical method is proven to predict the payload mass with an error never exceeding the 10% of the actual payload mass, found through numerical propagation. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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15 pages, 8648 KiB

Open AccessFeature PaperArticle

Analysis on the Isostatic Bipod Mounts for the HERA Mission LIDAR

by Nicole G. Dias, Paulo Gordo, Hugo Onderwater, Rui Melicio and António Amorim

Appl. Sci. 2022, 12(7), 3497; https://doi.org/10.3390/app12073497 - 30 Mar 2022

Cited by 8 | Viewed by 3304

Abstract

The Light Detection and Ranging (LIDAR) is a time-of-flight altimeter instrument being developed for the HERA mission, designated as Planetary ALTimeter (PALT). PALT is positioned in the center of the top face of the HERA probe, and therefore, it cannot use radiators to [...] Read more.

The Light Detection and Ranging (LIDAR) is a time-of-flight altimeter instrument being developed for the HERA mission, designated as Planetary ALTimeter (PALT). PALT is positioned in the center of the top face of the HERA probe, and therefore, it cannot use radiators to stabilize its internal temperature. The contribution of this paper is the design of isostatic bipod mounts for the LIDAR primary mirror. The performance of PALT must be maintained over a wide operational range, from −60 °C to 80 °C. These temperature requirements imply that a careful isostatic mount structure design is critical to maintaining performance in all operational scenarios. The purpose of the instrument is to perform range measurements from 500 m to 14 km. The instrument will contribute to the detailed characterization of the asteroid’s topography, assist the probe navigation in operations such as fly-bys (including on the dark side of the asteroid) or landing. PALT has an emitter system that generates 2 ns, 100 µJ, 1535 nm laser pulses and a receiver system that collects the backscattered signal from the asteroid. The receiver system is composed of a 70 mm diameter Cassegrain telescope and a refractive system that focuses the signal on the sensor. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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28 pages, 8998 KiB

Open AccessArticle

Passive Thermal Control Design Methods, Analysis, Comparison, and Evaluation for Micro and Nanosatellites Carrying Infrared Imager

by Shanmugasundaram Selvadurai, Amal Chandran, David Valentini and Bret Lamprecht

Appl. Sci. 2022, 12(6), 2858; https://doi.org/10.3390/app12062858 - 10 Mar 2022

Cited by 15 | Viewed by 7300

Abstract

Advancements in satellite technologies are increasing the power density of electronics and payloads. When the power consumption increases within a limited volume, waste heat generation also increases and this necessitates a proper and efficient thermal management system. Mostly, micro and nanosatellites use passive [...] Read more.

Advancements in satellite technologies are increasing the power density of electronics and payloads. When the power consumption increases within a limited volume, waste heat generation also increases and this necessitates a proper and efficient thermal management system. Mostly, micro and nanosatellites use passive thermal control methods because of the low cost, no additional power requirement, ease of implementation, and better thermal performance. Passive methods lack the ability to meet certain thermal requirements on larger and smaller satellite platforms. This work numerically studies the performance of some of the passive thermal control techniques such as thermal straps, surface coatings, multi-layer insulation (MLI), and radiators for a 6U small satellite configuration carrying a mid-wave infrared (MWIR) payload whose temperature needs to be cooled down to 100K. Infrared (IR) imagers require low temperature, and the level of cooling is entirely dependent on the infrared wavelengths. These instruments are used for various applications including Earth observations, defence, and imaging at IR wavelengths. To achieve these low temperatures on such instruments, a micro-cryocooler is considered in this study. Most of the higher heat dissipating elements in the satellite are mounted to a heat exchanger plate, which is thermally coupled to an external radiator using thermal straps and heat pipes. The effects of the radiator size, orbital inclinations, space environments, satellite attitude with respect to the sun, and surface coatings are discussed elaborately for a 6U satellite configuration. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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14 pages, 6975 KiB

Open AccessArticle

Transient Attitude Motion of TNS-0#2 Nanosatellite during Atmosphere Re-Entry

by Danil Ivanov, Dmitry Roldugin, Stepan Tkachev, Yaroslav Mashtakov, Sergey Shestakov, Mikhail Ovchinnikov, Igor Fedorov, Nikolay Yudanov and Artem Sergeev

Appl. Sci. 2021, 11(15), 6784; https://doi.org/10.3390/app11156784 - 23 Jul 2021

Cited by 2 | Viewed by 1589

Abstract

Attitude motion reconstruction of the Technological NanoSatellite TNS-0 #2 during the last month of its mission is presented in the paper. The satellite was designed to test the performance of the data transmission via the Globalstar communication system. This system successfully provided telemetry [...] Read more.

Attitude motion reconstruction of the Technological NanoSatellite TNS-0 #2 during the last month of its mission is presented in the paper. The satellite was designed to test the performance of the data transmission via the Globalstar communication system. This system successfully provided telemetry (even during its atmosphere re-entry) up to an altitude of 156 km. Satellite attitude data for this phase is analyzed in the paper. The nominal satellite attitude represents its passive stabilization along a geomagnetic field induction vector. The satellite was equipped with a permanent magnet and hysteresis dampers. The permanent magnet axis tracked the local geomagnetic field direction with an accuracy of about 15 degrees for almost two years of the mission. Rapid altitude decay during the last month of operation resulted in the transition from the magnetic stabilization to the aerodynamic stabilization of the satellite. The details of the initial tumbling motion after the launch, magnetic stabilization, transition phase prior to the aerodynamic stabilization, and subsequent satellite motion in the aerodynamic stabilization mode are presented. Full article

(This article belongs to the Special Issue Small Satellites Missions and Applications)

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