간행물
Journal of Astronomy and Space Sciences KCI 등재 SCOPUS
- 발행기관 한국우주과학회
- 자료유형 학술지
- 간기 계간
- ISSN 2093-5587 (Print)2093-1409 (Online)
- 수록기간 1984 ~ 2022
- 주제분류 자연과학 > 천문학 자연과학 분류의 다른 간행물
- 십진분류KDC 443DDC 520
권호리스트/논문검색
제31권 3호 (2014년 9월) 10건
Research Paper
1.
2014.09
서비스 종료(열람 제한)
We have investigated the dynamical stability of the proposed companions orbiting the Algol type short-period eclipsing binary SW Lyncis (Kim et al. 2010). The two candidate companions are of stellar to substellar nature, and were inferred from timing measurements of the system’s primary and secondary eclipses. We applied well-tested numerical techniques to accurately integrate the orbits of the two companions and to test for chaotic dynamical behavior. We carried out the stability analysis within a systematic parameter survey varying both the geometries and orientation of the orbits of the companions, as well as their masses. In all our numerical integrations we found that the proposed SW Lyn multi-body system is highly unstable on time-scales on the order of 1000 years. Our results cast doubt on the interpretation that the timing variations are caused by two companions. This work demonstrates that a straightforward dynamical analysis can help to test whether a best-fit companion-based model is a physically viable explanation for measured eclipse timing variations. We conclude that dynamical considerations reveal that the proposed SW Lyncis multi-body system most likely does not exist or the companions have significantly different orbital properties from those conjectured in Kim et al. (2010).
2.
2014.09
서비스 종료(열람 제한)
This paper intends to highlight the effect of the third-body in an inclined orbit on a spacecraft orbiting the primary mass. To achieve this goal, a new origin of coordinate is introduced in the primary and the X-axis toward the node of the spacecraft. The disturbing function is expanded up to the second order using Legendre polynomials. A double-averaged analytical model is exploited to produce the evolutions of mean orbital elements as smooth curves.
3.
2014.09
서비스 종료(열람 제한)
In this study, a star identification algorithm which utilizes pivot patterns instead of apparent magnitude information was developed. The new star identification algorithm consists of two steps of recognition process. In the first step, the brightest star in a sensor image is identified using the orientation of brightness between two stars as recognition information. In the second step, cell indexes are used as new recognition information to identify dimmer stars, which are derived from the brightest star already identified. If we use the cell index information, we can search over limited portion of the star catalogue database, which enables the faster identification of dimmer stars. The new pivot algorithm does not require calibrations on the apparent magnitude of a star but it shows robust characteristics on the errors of apparent magnitude compared to conventional pivot algorithms which require the apparent magnitude information.
4.
2014.09
서비스 종료(열람 제한)
In this paper, we report the analysis of Korean historical records on the periodic Halley’s comet according to the period (i.e., the Three Kingdoms, Goryeo Dynasty, and Joseon Dynasty) using various sources such as the Samguksagi (The History of the Three Kingdoms), Goryeosa (The History of the Goryeo Dynasty), and Joseonwangjosillok (The Annals of the Joseon Dynasty). With regards to the apparition time of the comet for each return, we referred to the works of Kronk. For the Three Kingdoms period, we could not find any record relevant to Halley’s comet from the Samguksagi. Furthermore, we examined the suggestion that the phenomenon of “two Suns” which appeared on April 1, 760 (in a luni-solar calendar), as recorded in the Samgukyusa (The Legends and History of the Three Kingdoms), indicates an instance of the the daytime appearance of Halley’s comet. In contrast with the Three Kingdoms period, we found that all returns of Halley’s comet are recorded during the Goryeo Dynasty, although others have questioned some accounts. We also found that the appearance of Halley’s comet in 1145 is mentioned in a spirit-path stele made in 1178. For the Joseon Dynasty period, we found that all apparitions of the comet are recorded, as with the Goryeo Dynasty, except for the return of 1910, at which time the former dynasty had fallen. In conclusion, we think that this study will be helpful for understanding Korean historical accounts on Halley’s comet.
Technical Paper
5.
2014.09
서비스 종료(열람 제한)
Man-Soo Choi, Hyung-Chul Lim, Eun-Jung Choi, Eunseo Park, Sung-Yeol Yu, Seong-Cheol Bang, Tae-Keun Kim, Young-Rok Kim, Dong-Jin Kim, Kipyung Seong, Neung-Hyun Ka, Cer-Hee Choi, Joo-Yeon Hwang, Daniel Kucharski, In-Woo Han, Jakyoung Nah, Jung-Guen Jang, Bi-Ho Jang, Sang-Jung Lee
The first Korean satellite laser ranging (SLR) system, Daedeok SLR station (DAEK station) was developed by Korea Astronomy and Space Science Institute (KASI) in 2012, whose main objectives are space geodesy researches. In consequence, Korea became the 25th country that operates SLR system supplementing the international laser tracking network. The DAEK station is designed to be capable of 2 kHz laser ranging with precision of a few mm both in daytime and nighttime observation of satellites with laser retro-reflector array (LRA) up to the altitude of 25,000 km. In this study, characteristics and specifications of DAEK station are investigated and its data quality is evaluated and compared with International Laser Ranging Service (ILRS) stations in terms of single-shot ranging precision. The analysis results demonstrated that the DAEK station shows good ranging performance to a few mm precision. Currently, the DAEK station is under normal operations at KASI headquarters, however, it will be moved to Sejong city in 2014 to function as a fundamental station for space geodesy researches in combination with other space geodesy systems (GNSS, VLBI, DORIS, etc.).
6.
2014.09
서비스 종료(열람 제한)
The communications link in a space program is a crucial point for upgrading its performance by handling data between spacecraft bus and payloads, because spacecraft’s missions are related to the data handling mechanism using communications ports such as a controlled area network bus (CAN Bus) and a universal asynchronous receiver and transmitter (UART). The NEXTSat-1 has a lot of communications ports for performing science and technology missions. However, the top level system requirements for the NEXTSat-1 are mass and volume limitations. Normally, the communications for units shall be conducted by using point to point link which require more mass and volume to interconnect. Thus, our approach for the novel communications link in the NEXTSat-1 program is to use CAN and serializer and deserializer low voltage differential signal (SerDesLVDS) to meet the system requirements of mass and volume. The CAN Bus and SerDesLVDS were confirmed by using already defined communications link for our missions in the NEXTSat-1 program and the analysis results were reported in this study in view of data flow and size analysis.
7.
2014.09
서비스 종료(열람 제한)
The Amon-Ra instrument is the main optical payload of the proposed EARTHSHINE satellite. It consists of a visible wavelength instrument and an IR energy channel instrument to measure a global Earth albedo. We report a new sensitivity technique for efficient alignment of the visible channel instrument. Whilst the sensitivity table method has been widely used in the alignment process, the straightforward application of the method tends to produce slow process convergence because of shop floor alignment practice uncertainties. We investigated the error sources commonly associated with alignment practices and used them when estimating the Zernike polynomial coefficients. Aided with single center field wavefront error (WFE) measurements and their corresponding Zernike polynomial coefficients, the method involves the construction and use of an experimental, instead of simulated, sensitivity table to be used for alignment state estimations. A trial alignment experiment for the Amon Ra optical system was performed and the results show that 71.28 nm in rms WFE was achieved only after two alignment iterations. This tends to demonstrate its superior performance to the conventional method.
8.
2014.09
서비스 종료(열람 제한)
In this paper, a brief but essential development strategy for the lunar orbit determination system is discussed to prepare for the future Korea’s lunar missions. Prior to the discussion of this preliminary development strategy, technical models of foreign agencies for the lunar orbit determination system, tracking networks to measure the orbit, and collaborative efforts to verify system performance are reviewed in detail with a short summary of their lunar mission history. Covered foreign agencies are European Space Agency, Japan Aerospace Exploration Agency, Indian Space Research Organization and China National Space Administration. Based on the lessons from their experiences, the preliminary development strategy for Korea’s future lunar orbit determination system is discussed with regard to the core technical issues of dynamic modeling, numerical integration, measurement modeling, estimation method, measurement system as well as appropriate data formatting for the interoperability among foreign agencies. Although only the preliminary development strategy has been discussed through this work, the proposed strategy will aid the Korean astronautical society while on the development phase of the future Korea’s own lunar orbit determination system. Also, it is expected that further detailed system requirements or technical development strategies could be designed or established based on the current discussions.
9.
2014.09
서비스 종료(열람 제한)
The application of software engineering is not common in the development of astronomical observation system. While there were component-wise developments in the past, large-scale comprehensive system developments are more common in these days. In this study, current methodologies of development are reviewed to select a proper one for the development of astronomical observation system and the result of the application is presented. As the subject of this study, a project of operation software development for an astronomical observation system which runs on the ground is selected. And the output management technique based on Component Based Development which is one of the relatively recent methodologies has been applied. Since the nature of the system requires lots of arithmetic algorithms and it has great impact on the overall performance of the entire system, a prototype model is developed to verify major functions and performance. Consequently, it was possible to verify the compliance with the product requirements through the requirement tracing table and also it was possible to keep to the schedule. Besides, it was suggested that a few improvements could be possible based on the experience of the application of conventional output management technique. This study is the first application of the software development methodology in the domestic astronomical observation system area. The process and results of this study would contribute to the investigation for a more appropriate methodology in the area of similar system development.
10.
2014.09
서비스 종료(열람 제한)
Gyeong-Bok Jo, Jongdae Sohn, Cheong Rim Choi, Yu Yi, Kyoung-Wook Min, Suk-Bin Kang, Go Woon Na, Goo-Hwan Shin
Next Generation Small Satellite-1 (NEXTSat-1) is scheduled to launch in 2017 and Instruments for the Study of Space Storm (ISSS) is planned to be onboard the NEXTSat-1. High Energy Particle Detector (HEPD) is one of the equipment comprising ISSS and the main objective of HEPD is to measure the high energy particles streaming into the Earth radiation belt during the event of a space storm, especially, electrons and protons, to obtain the flux information of those particles. For the design of HEPD, the Geometrical Factor was calculated to be 0.05 to be consistent with the targets of measurement and the structure of telescope with field of view of 33.4° was designed using this factor. In order to decide the thickness of the detector sensor and the classification of the detection channels, a simulation was performed using GEANT4. Based on the simulation results, two silicon detectors with 1 mm thickness were selected and the aluminum foil of 0.05 mm is placed right in front of the silicon detectors to shield low energy particles. The detection channels are divided into an electron channel and two proton channels based on the measured LET of the particle. If the measured LET is less than 0.8 MeV, the particle belongs to the electron channel, otherwise it belongs to proton channels. HEPD is installed in the direction of 0°,45°,90° against the along-track of a satellite to enable the efficient measurement of high energy particles. HEPD detects electrons with the energy of 0.1 MeV to several MeV and protons with the energy of more than a few MeV. Thus, the study on the dynamic mechanism of these particles in the Earth radiation belt will be performed.
