• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.10
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• pp.728-737
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• 2019

In this study, the minimized on-board computer (OBC) module for integrated navigation is developed, which provides satellites' relative position information in formation flying and cluster operation situations. The scalability is considered to apply the user-selected wireless communication module and Global Positioning System (GPS) receiver for navigation, while considering to meet the structural design standard of nano-satellites. As a result of the product development and production, the processing speed of integrated navigation and real-time data synchronization is satisfied for cluster operation nano-satellites by using micro controller unit (MCU). From a heat/vacuum, vibration and radiation test, the OBC was confirmed to be operated in space environments. From these results, a mass production system of OBC was made which is a key part of development on satellite formation flying and cluster/constellation missions that the community demands are increasing.

• Journal of Space Technology and Applications
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• v.4 no.1
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• pp.62-73
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• 2024

This study analyzed the effectiveness of orbital change through attitude change in nano-satellites operating in low Earth orbit (LEO) without thrusters, focusing on collision avoidance maneuvers. The results revealed that changes in the satellite's cross-sectional area significantly impact its in-track direction, influenced by the aspect ratio of cross-sectional area change and mission altitude. Notably, satellites at lower altitudes demonstrated significant reduction in collision risks with a small amount of attitude change. Through this study, it is judged that the changing the cross-sectional area through attitude maneuver is a sufficiently suitable method in the operation of nano-satellites without thrusters, and is expected to contribute to improving the safety of satellite operations in the New Space era.

• Journal of Advanced Navigation Technology
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• v.21 no.3
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• pp.213-219
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• 2017

Large satellite development programs might take decades to build, launch and operate in space environments at costs in excess of a billion dollars. However, small satellites can reduce the costs not only by using commercial software and sensors, but also by shortening the development period to two years or less. In this paper, we discuss the development status of small satellites, and propose some military applications of small satellites. First, we describe the industrial trends of small satellites in advanced countries such as the United States and Japan. Also, we describe the development status of small satellites in Korea. Military applications are largely classified into education, research, and operational purposes. Small satellites are developing rapidly in commercial markets and they will play an important role in military sector. Therefore, the military should consider small satellites as important strategic assets in future conflicts and provide means to develop them.

• Advances in aircraft and spacecraft science
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• v.4 no.6
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• pp.729-744
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• 2017

This investigation highlights rationale of electrically conductive nano adhesives for its essential application for Electromagnetic Interference (EMI) Shielding in satellites and Lightning Strike Protection in aircrafts. Carbon Nano Fibres (CNF) were functionalized by electroless process using Tollen's reagent and by Plasma Enhanced Chemical Vapour Deposition (PECVD) process by depositing silver on CNF. Different weight percentage of CNF and silver coated CNF were reinforced into the epoxy resin hardener system. Scanning Electron Microscopy (SEM) micrographs clearly show the presence of CNF in the epoxy matrix, thus giving enough evidence to show that dispersion is uniform. Transmission Electron Microscopy (TEM) studies reveal that there is uniform deposition of silver on CNF resulting in significant improvement in interfacial adhesion with epoxy matrix. There is a considerable increase in thermal stability of the conductive nano adhesive demonstrated by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Four probe conductivity meters clearly shows a substantial increase in the electrical conductivity of silver coated CNF-epoxy composite compared to non-coated CNF-epoxy composite. Tensile test results clearly show that there is a significant increase in the tensile strength of silver coated CNF-composites compared to non-coated CNF-epoxy composites. Consequently, this technology is highly desirable for satellites and EMI Shielding and will open a new dimension in space research.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.2
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• pp.127-135
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• 2022

Compared to the continuous increase of domestic nano-satellite development cases, the initial communication success rate is relatively low. In a situation where communication cases of LEO satellites using commercial satellite communication networks are increasing recently. In this situation, the SNIPE project developed by the KASI(Korea Astronomy and Space Science Institute), KARI(Korea Aerospace Research Institute), and Yonsei University apply an Iridium module for communication test to the SNIPE nano-satellites. Therefore, in this paper, the visibility analysis of the iridium module on the SNIPE satellite was analyzed under considering the orbital and communication environment of the iridium satellite constellation and the attitude control mode. In the case of LEO satellites, the communication possibility was limited due to the relatively small iridium communication coverage for high altitude and the high doppler shift considered in the iridium communication network. For this reason, in this paper, it could be simulated that there was a more performance difference according to the difference in relative RAAN(Right Ascension of Ascending Node) angle with the Iridium constellation. Finally, by checking the visibility of communication module under the tumbling situation that occurred during the initial deployment of the nano-satellite, the possibility of using the iridium communication technology was analyzed.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.5
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• pp.36-52
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• 2021

As the application of nano-satellites constellation increases worldwide in the wake of New Space era, there is growing demand for the development of thrusters for precise attitude and orbit control of small satellites. Field Emission Electric Propulsion(FEEP) thruster uses a liquid metal as a propellant and accelerates the ionized liquid metal through a strong electric field at the tip of the metal surface. FEEP thruster technology is suitable for nano-satellites which require various missions for attitude and orbit control, because it provides thrust ranging from 1 µN to 1 mN with high specific impulse up to about 10,000 s and can be miniaturized due to its simple structure. In this paper, the basics of FEEP thrusters are introduced, then the current status of research and development of FEEP thrusters are presented.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.11
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• pp.997-1005
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• 2016

Flight software plays an important role in operating satellites, such as processing commands from ground station, controlling satellites and processing mission data. Reliability is the most important thing in flight software and many verifications and tests are needed for assuring it. this causes an increase of cost and period of development. So NASA has developed a reusable flight software platform to apply to their satellite projects. The CFS(Core Flight System) is the very result. We are developing our flight software for a nano-satellite based on NASA CFS. We have tested core services and functions provided in CFS and we have designed and implemented flight software based on these.

• Journal of Aerospace System Engineering
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• v.18 no.2
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• pp.21-28
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• 2024

In light of the rapid development of the space industry, there has been increased attention on small satellites. These satellites rely on components that are considered to have lower reliability compared to larger-scale satellites. As a result, predicting reliability becomes even more crucial in this context. Therefore, this study aims to compare three reliability prediction techniques: MIL-HDBK-217F, RiAC-HDBK-217Plus, and FIDES. The goal is to determine a suitable reliability standard specifically for nano-satellites. Furthermore, we have refined the quality assurance factors of the manufacturing company. These factors have been adjusted to be applicable across various industrial sectors, with a particular focus on the selected FIDES prediction standard. This approach ensures that the scoring system accurately reflects the suitability for the aerospace industry. Finally, by implementing this refined system, we confirm the impact of the manufacturer's quality assurance level on the total failure rate.

• Journal of Aerospace System Engineering
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• v.12 no.3
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• pp.26-37
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• 2018

The Korea Aerospace Research Institute has developed a 6U HiREV Nano-satellite for the observation of the earth using high resolution videos and images. Since the 6U Nano-satellite is bulky compared to the 1U/3U Nano-satellite, the first natural frequency is relatively low. Large equivalent stress and total deformation, due to structural load, can be generated. In this paper, the design of the 6U HiREV Nano-satellite is described and structure analysis, such as acceleration load analysis, modal analysis, and random vibration analysis are carried out. It is proven that the structural design of the 6U HiREV is stable. These results will be useful as reference materials for the development of additional 6U Nano-satellites, which will be applied to various future missions in KOREA.

• Journal of Astronomy and Space Sciences
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• v.39 no.3
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• pp.109-116
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• 2022

The small-scale magnetospheric and ionospheric plasma experiment (SNIPE) is a mission initiated by the Korea Astronomy and Space Science Institute (KASI) in 2017 and comprises four 6U-sized nano-satellites (Korea Astronomy and Space Science Institute Satellite-1, KASISat-1) flying in formations. The main goal of the SNIPE mission is to investigate the space environment in low Earth orbit at 500-km. Because Iridium & GPS Board (IGB) is installed on the KASISat-1, a communication simulation is required to analyze the contact number and the duration. In this study, communication simulations between the Iridium satellite network and KASISat-1 are performed using STK Pro (System Tool Kit Pro Ver 11.2) from the AGI (Analytical Graphics, Inc.). The contact number and durations were analyzed by each orbit and date. The analysis shows that the average access number per day is 38.714 times, with an average of 2.533 times per orbit for a week. Furthermore, on average, the Iridium satellite communication is linked for 70.597 min daily. Moreover, 4.625 min is the average duration of an individual orbit.