• Journal of Positioning, Navigation, and Timing
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• v.9 no.1
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• pp.1-6
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• 2020

The Chinese BeiDou Satellite Navigation System consists of three kinds of constellations: the geostationary Earth orbit (GEO), the inclined geosynchronous satellite orbit (IGSO), and the medium Earth orbit (MEO). The BeiDou has expanded its service coverage from regional to global. Recently, the BeiDou has been widely used in ionospheric total electron content (TEC) research. In this study, we analyzed the BeiDou signals for ionospheric TEC monitoring over Jeju Island in South Korea. The BeiDou GEO TEC showed a clear pattern of diurnal variations. In addition, we compared the TEC values from the BeiDou GEO, the BeiDou IGSO, GPS, and International GNSS Service (IGS) Global Ionosphere Maps (GIM). There was a difference of about 5 TEC units between the BeiDou GEO and the IGS GIM. This may be due to the altitude difference between the different navigation satellites.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.4
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• pp.398-404
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• 2007

In this paper, thermal characteristics of a nitrous oxide ($N_2O$) catalytic reactor with packed-bed geometry are theoretically and numerically investigated. Several researchers experimentally presented that catalytic decomposition of $N_2O$ in a packed bed generates about 82kJ/mole in the exothermic reaction. Based on the results they have studied the catalytic decomposition of $N_2O$ in a packed bed to use it not only as a mono-propellant thrust for small satellites but also as an igniter system for hybrid rockets. So we aim to identify important parameters existing in an $N_2O$ packed-bed geometry, and to clarify its critical effect on thermal characteristics of the catalytic igniter using a porous medium approach.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.169-171
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• 2015

NGC147 and NGC185, paired satellites of the Andromeda galaxy, possess the same order of mass and analogous structures, but they show different star formation and different amounts of interstellar gas and dust. Therefore, we present the first reconstruction of the star formation history of NGC147 and NGC185. Asymptotic Giant Branch stars are highly evolved stars that are brightest in K-band. This maximum K-band magnitude is related to the birth mass of stars. As a result, we have found a 9.9 Gyr old single star formation epoch for NGC185 followed by relatively continuous star formation. NGC147, however, has passed through two star formation episodes; one is as old as ~6 Gyr and the other is as recent as ~850 Myr. Asymptotic Giant Branch stars are also important dust factories; by fitting Spectral Energy Distributions to observed near and mid infrared data for each star, we were able to measure the dust production rates of individual stars; on order of $10^{-5}M_{\odot}yr^{-1}$. Hence, we estimate the total mass entering the interstellar medium to be $1.06{\times}10^{-4}M_{\odot}yr^{-1}$ and $2.89{\times}10^{-4}M_{\odot}yr^{-1}$ for NGC147 and NGC185.

• Korean Journal of Remote Sensing
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• v.39 no.5_2
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• pp.755-770
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• 2023

Due to recent severe climate change, abnormal weather phenomena, and other factors, the frequency and magnitude of natural disasters are increasing. The need for disaster management using artificial satellites is growing, especially during large-scale disasters due to time and economic constraints. In this study, we have summarized the current status of next-generation medium-sized satellites and microsatellites in operation and under development, as well as trends in satellite imagery analysis techniques using a large volume of satellite imagery driven by the advancement of the space industry. Furthermore, by utilizing satellite imagery, particularly focusing on recent major disasters such as floods, landslides, droughts, and wildfires, we have confirmed how satellite imagery can be employed for damage analysis, thereby establishing its potential for disaster management. Through this study, we have presented satellite development and operational statuses, recent trends in satellite imagery analysis technology, and proposed disaster response strategies that utilize various types of satellite imagery. It was observed that during the stages of disaster progression, the utilization of satellite imagery is more prominent in the response and recovery stages than in the prevention and preparedness stages. In the future, with the availability of diverse imagery, we plan to research the fusion of cutting-edge technologies like artificial intelligence and deep learning, and their applicability for effective disaster management.

• The Korean Journal of Air & Space Law and Policy
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• v.20 no.1
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• pp.9-43
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• 2005

The Korean government established her first "National Space Program" in 1996, and revised it in 2000 and 2005. As embedded in the National Space Program, Korea aims to become one of the world's top countries in space technology by 2010. All of 13 satellites are planned to be put into orbit as schematized, which include 7 multi-purpose satellites, 4 science satellites and 2 geostationary orbit satellites. The Space Center in Korea is to be built at Woinara-Do, Bongrae-Myon, Koheung-Goon, Junlanam Province on the southern coast of the Korean peninsular. The first phase of the construction of the space center will be finished by 2007 for launch of KSLV-l. This will make Korea be the 13th advanced country in space development having a launching site in the world. The "Space Center" will serve as the infrastructure for the development of space technology and related technology, and plan to launch a low earth orbit satellite in 2007. A second science satellite made in Korea will be launched from the space center by 2007. From 2010, the center will be operated on a commercial basis operating launch facilities for low-to mid-altitude orbit satellites. Since the 'Aircraft Industry Promotion Act' was replaced by the 'Aerospace Industry Development Promotion Acf of 1987, this Act had been amended seven times from 1991 year to 2004. Most of developed countries has been enacted the space law including the public or private items such as an (1)DSA, (2)Russia, (3)the United Kingdom, (4)Germany, (5)France, (6)Canada, (7)Japan, (8)Sweden, (9)Australia, (10)Brazil, (11)Norway, (12)South Africa, (13)Argentina, (14)Chile, (15)Ukrainian etc. As the new Space Exploration Promotion Act was passed by the resolution of the Korean Congress on May 3, 2005, so the Korean government has made the public proclamation the abovementioned Act on May 31, this year. This Act takes effect on December 1, 2005 after elapsing six months from the date of promulgation. The main contents of Space Exploration Promotion Act of 2005 is as the following (1)establishing a basic plan for promoting space exploration, (2)establishment and function of national space committee, (3)procedure and management of domestic and international registration of space objects, (4)licensing of launch by space launch vehicles, (5)lability for damages caused by space accidents and liability insurance, (6) organizing and composition of the space accident investigation committee, (7)Support of non-governmental space exploration project, (8)Requesting Support and Cooperation of Space Exploration, (9)Rescue of Astronauts and Restitution of Space Objects, etc.. In oder to carry out successfully the medium and long basic plan for promoting space exploration and to develope space industry in Korea, I think that it is necessary for us to enlarge and to reorganize the function and manpower of the Space Technology Development Division of the Ministry of Science & Technology and the Korea Aerospace Research Institute. Korea has been carrying out its space program step by step according to the National Space Program. Korea also will continually strengthen the exchange and cooperation with all the countries in the world under the principle of equality, friendship relations and mutual benefits. Together with all other peoples around the globe, Korea will make due contribution towards the peaceful utilization of space resources and promotion of human progress and prosperity.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.14-21
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• 2013

In satellite operations and space exploration missions, a ranging is one of the most essential technologies to get its navigational information of space probes. Recently, the importance of cross-support between space agencies is increasing for more fine performance of space mission. For cross-support, mutually compatible ranging system between space agencies is recommended. For these reasons, the consultative committee for space data systems (CCSDS) recommends pseudo noise (PN) ranging as a digital standard ranging system. The length of PN sequence in CCSDS standard is proper for deep space missions, however, it is too long to use for ranging in near earth missions. In this paper, we propose Variable Length PN sequence schemes suitable for ranging of near earth satellites, such as low-earth orbit (LEO), medium-earth orbit (MEO) and Geostationary orbit (GEO). Therefore we propose variable length PN sequence ranging system including CCSDS standard for multiple missions.

• Journal of Astronomy and Space Sciences
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• v.37 no.3
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• pp.209-218
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• 2020

This paper describes the initial operations and preliminary results of the Instrument for the study of Stable/Storm-time Space (ISSS) onboard the microsatellite Next Generation Small Satellite-1 (NEXTSat-1), which was launched on December 4, 2018 into a sun-synchronous orbit at an altitude of 575 km with an orbital inclination angle of 97.7°. The spacecraft and the instruments have been working normally, and the results from the observations are in agreement with those from other satellites. Nevertheless, improvement in both the spacecraft/instrument operation and the analysis is suggested to produce more fruitful scientific results from the satellite operations. It is expected that the ISSS observations will become the main mission of the NEXTSat-1 at the end of 2020, when the technological experiments and astronomical observations terminate after two years of operation.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.104-109
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• 2016

A technology of GEO satellite communications starts from Koreasat program in Korea. Payload equipment of EQM Ku and Ka band transponders had been developed and space-qualified Ka band payload in COMS was successfully launched in June, 2010. For the purpose of military communications, Dehop-Rehop transponder was developed in Koreasat5 as ANASIS system and DAT(Digital Active Transponder) and DCAMP(Digital Channel AMPlifier) transponders are now under development. In this paper, from the study of military satellite communications trend, a direction of military communication satellite is suggested based on the current GEO SATCOM technologies in Korea. Considering the limit of frequency resources, a technology of battlefield adaptive transponder with medium capacity against high moveable jamming tactics would be efficient for the future military SATCOM system. Mid-sized military satellites with frequency hopping and mid-capacity transponders can be a solution of vitalizing the GEO satellite programs.

• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.1-6
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• 2014

The increasing demands and utilization of the multi-purpose satellites have led to diverse research activities with regards to satellite image processing and applications. In this paper, the research activities of satellite images is investigated relevant to domestic agricultural activities in past 5 years and the system characteristics of the related spaceborne payload is analyzed. For this purpose, a broad range of research materials has been collected published in past years and a statistical analysis is performed to classify the use of satellite images. Overall the current work is aimed to carry out a comprehensive analysis on the current status of satellite imaging in agricultural sectors. Furthermore, this paper can be utilized to identify and support the incoming satellite development plan utilizing medium imaging capabilities specially in the field of agricultural uses.

• Korean Journal of Plant Taxonomy
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• v.39 no.3
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• pp.220-228
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• 2009

C-banded karyotypes of eight taxa of Korean Allium sect. Sacculiferum were examined by means of Giemsa techniques. Each of the taxa had their own characteristic bands. Most of the bands on the somatic metaphase chromosomes were mainly located on the short arm, intercalary region and medium sized chromosomes. In addition, the heterochromatic bands were usually facultative, recognized as two spots, and all investigated taxa had a pair of satellites of heterochromatin. The similarities of total length and number of bands revealed that three varieties of A. thunbergii G. Don have a closer cytological relationship than the others. The C-banding patterns of A. longistylum and A. linearifolium were examined for the first time in this study, and the former was clearly distinguished from the others by the distribution and number of its bands. The proportion of heterochromatic bands suggested that A. thunbergii var. thunbergii is the most primitive, and A. sacculiferum the most advonced, within the section.