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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Astronomy and Space Sciences
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The Korean Space Science Society
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Volume & Issues
Volume 20, Issue 4 - Dec 2003
Volume 20, Issue 3 - Sep 2003
Volume 20, Issue 2 - Jun 2003
Volume 20, Issue 1 - Mar 2003
Selecting the target year
LIGHT CORVES AND ROCHE CONFIGURATIONS OF NEAR-CONTACT BINARY AX DRACONIS
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 239~248
DOI : 10.5140/JASS.2003.20.4.239
We completed the light curves of near-contact binary system AX Dra for 11 nights from March 2001 to May using the 61-cm reflector and VR filters at Sobaeksan Optical Astronomy Observatory. From our observations, seven new times of minimum light (three timings to. primary eclipse, four. for. secondary) and the light elements consistent with recent observations were determined. Using the Wilson-Devinney binary code and the q-search method, we analyzed our VR light curves for various Roche configurations and mass ratios. As the results, we found the eclipsing binary AX Dra to be the FO Vir-type near-contact binary system interpreted as a detached or a semi-detached system, with the secondary filling its Roche lobe and the primary almost. Unlike the statistical study(Shaw 1994) of the FO Vir-type near-contact binary system, our VR light curves showed the O'Connell effect of all the same type and it's dimensions was about
PHOTOMETRIC STUDY OF A W UMa TYPE CONTACT BINARY AH CNC
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 249~260
DOI : 10.5140/JASS.2003.20.4.249
CCD photometric observations of a W UMa type contact binary AH Cnc were performed for ten nights from December 1998 to May 1999 using a PM512 CCD camera and BVI filters attached to the 61㎝ reflector at Sobaeksan Optical Astronomy Observatory. New BVI light curves were analyzed with contact Mode 3 of the Wilson-Devinney binary model. We obtained photometric solutions and Roche geometry of this binary system. Through the analysis of the (O-C) diagram with all times of minimum light published so far and including hour's secular variations of orbital period and the mass transfer rate were calculated.
ON THE APSIDAL MOTION OF IQ PERSEI
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 261~268
DOI : 10.5140/JASS.2003.20.4.261
CCD observations of times of minimum light of IQ Per with apsidal motion were made in VR bandpasses for four nights from November to December, 2002. From the observations four times of minimum light were determined. All times of minimum light collected from literatures, including ours, were analyzed to determine the apsidal motion parameters of IQ per. The sidereal and apsidal motion periods were calculated to be
slightly longer than those of Degirmenci (1997), respectively. The apsidal motion parameters of IQ Per derived in this paper show good agreement with Degirmenci's values. Our results support his internal density constant of
= 0.0038 for IQ Per and 5 % accuracy of agreement between the observed and modelled values of the apsidal motion constant.
TERRESTRIAL IMPACT CRATERING CHRONOLOGY II : PERIODICITY ANALYSIS WITH THE 2002 DATABASE
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 269~282
DOI : 10.5140/JASS.2003.20.4.269
We examined the hypothesis that the crater formation rate exhibits periodicity, employing data sets of Grieve (1991), Moon et al. (2001), and the Earth Impact Database(2002; DB02). DB02 is known to supercede previous compilations in terms of its accuracy and precision of the ages; it is the first time that this database has been used for periodicity analysis. For data sets comprising impact structures with
(and also those with
), there is no convincing evidence for periodicities in the crater ages, according to our Fourier analysis. However, we detected two peaks at 16.1Myr and 34.7Myr for craters with
; we confirm that the age distribution of impact craters with
has dominant power at 16.1Myr. Thus, we may conjecture a probable periodic shower of Earth impactors with sizes
. In addition, we found that the selection of data sets, the lower limits on the ages and diameters of impact craters, as well as the accuracy and precision of the ages, all constitute crucial factors in reconstructing the impact cratering history of the Earth.
ALL-SKY OBSERVATION OF THE 2001 LEONID METEOR STORM: 1. METEOR MAGNITUDE DISTRIBUTION
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 283~298
DOI : 10.5140/JASS.2003.20.4.283
The 2001 Leonid meteor storm has been observed all over the world, and its most intense flux since the last few decades has caused great interest among both laymen and experts. Especially, its maximum hours occurred at dawn hours of Nov. 19 in the east Asia, during which moonless clear night at the Mt. Bohyun allowed us near perfect condition of observation. Observation was carried out in the period of 01:00∼05:40(KST), which include the predicted maximum hours, with all-sky camera installed for upper atmospheric airglow research. Tn this paper we analyze 68 all-sky images obtained in this period, which contain records of 172 meteors. Utilizing the zenith hourly rate(ZHR) of 3000 and magnitude distribution index of 2, which were reported to International Meteor Organization by visible observers in the east Asia, we estimate the limiting magnitude of about 3 for meteors detected in our all-sky images. We then derive magnitudes of 83 meteors with clear pixel brightness outlines among the initially detected 172 meteors by comparing with neighbor standard stars. Angular velocities of meteors needed for computing their passing times over an all-sky image are expressed with a simple formula of an angle between a meteor head and the Leonid radiant point. The derived magnitudes of 83 meteors are in the range of -6∼-1 magnitude, and its distribution shows a maximum new -3mag. The derived magnitudes are much smaller than the limiting magnitude inferred from the comparison with the result of naked-eye observations. The difference may be due to the characteristic difference between nearly instantaneuous naked-eye observations and CCD observations with a long exposure. We redetermine magnitudes of the meteors by adjusting a meteor lasting time to be consistent with the naked-eye observations. The relative distribution of the redetermined magnitudes, which has a maximum at 0 mag., resembles that of the magnitudes determined with the in-principle method. The relative distribution is quite different from ones that decrease monotonically with decreasing magnitudes for meteors(1∼6) sensitive to naked-eye observations. We conclude from the magnitude distribution of our all-sky observation that meteors brighter than about 0 mag., appeared more frequently during the 2001 Leonid maximum hours. The frequent appearance of bright meteors has significantly important implication for meteor research. We noted, however, considerably large uncertainties in magnitudes determined only by comparing standard stars due to the unknown lasting time of meteors and the non-linear sensitivity of all-sky camera.
EARTH TO MARS BALLISTIC MISSION OPPORTUNITIES FROM NARO SPACE CENTER
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 299~312
DOI : 10.5140/JASS.2003.20.4.299
Earth to Mars ballistic mission opportunities from Naro Space Center are studied. Determining ballistic mission opportunities can be divided into two major parts, i.e. the launch window and the daily launch window determination. At the launch window determination parts, Porkchop diagrams of Earth launch C3 magnitude, total mission duration, declination of
vector at the Earth launch, and declination & right ascension of
vector at the Mars arrival are examined. The location of launch site and rotation effects of the Earth are considered during the daily launch window determination parts. Using Lambert method, various Porkchop diagrams of launching in 2027 are examined for example. The daily launch window of Naro Space Center at that year was checked to verify the launch possibility by comparing with the Kennedy Space Center.
COMMUNICATIONS SATELLITE SYSTEM BY USING MOON ORBIT SATELLITE CONSTELLATION
Lee, Sang-Uk ; Kim, Jae-Hoon ; Lee, Seong-Pal ;
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 313~318
DOI : 10.5140/JASS.2003.20.4.313
A communications satellite system placed in three-Lagrange points,
, of the restricted three-body problem in Earth-Moon system is proposed in this paper. LEO satellite constellation has been another choice of communications system. The proposed system which is alternatives of limited geostationary orbit resources, has some weak points such as long distance from the Earth, relatively expensive launch cost, long delay time, more required power, and so on. It has good points like less efforts (fuel) for station keeping, less eclipses, etc. This system has limitations for applications to provide commercial services but it is still some attractive points.
ANALYSIS OF THE MOTION OF A TETHER-PERTURBED SATELLITE
Cho, Sung-Ki ; Kim, Jae-Hoon ;
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 319~326
DOI : 10.5140/JASS.2003.20.4.319
The motion of each satellite in a tethered satellite system is non-Keplerian in the Earth's gravitational field. In this paper, the tether perturbation force is formulated and compared with the perturbation force due to the Earth's oblateness. Also, the center of mass motion of the tethered satellite system is analyzed. The tether perturbing force on the one of satellites in a tethered satellite system is much bigger than the Earth's oblateness perturbation. The two-body motion approximation of the center of mass is acceptable to describe the motion of the system, when the libration is small.
DEVELOPMENT OF THE SOLAR EUV TELESCOPE ENGINEERING MODEL FOR A SATELLITE
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 327~338
DOI : 10.5140/JASS.2003.20.4.327
The aim of this paper is to describe the results of the study on the extreme-ultra-violet (EUV) solar telescope, which is designed to. a possible satellite mission. Since the EUV band can not be observed on the ground, the observation in EUV should be performed in space using a satellite or a rocket. Design of the Extreme-Ultra-Violet solar Telescope (BUVT) in this study is based on "Designing a small-sized engineering model of solar EUV telescope for a Korean satellite" (Han et al. 2001). Our EUVT design is satisfied with the requirements for a satellite in size and input voltage. The major goal of the study is to confirm if we can detect the specific wavelength (58.4nm to 62.9nm) with the EUVT. We describe re-designing of the EUVT to decrease a shelter ratio. Also we describe the technics in the optic system and the detector, which were used to manufacture the EUVT. We explain the detective program, which is to calculate the amount of the solar radiation, and the image data processing system.ng system.
DESIGN AND IMPLEMENTATION OF HITL SIMULATOR COUPLEING COMMUNICATIONS PAYLOAD AND SOFTWARE SPACECRAFT BUS
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 339~350
DOI : 10.5140/JASS.2003.20.4.339
Engineering qualification model payload for a communications and broadcasting satellite(CBS) was developed by ETRI from May, 2000 to April, 2003. For. the purpose of functional test and verification of the payload, a real-time hardware-in-the-loop(HITL) CBS simulator(CBSSIM) was also developed. We assumed that the spacecraft platform for the CBSSIM is a geostationary communication satellite using momentum bias three-axis stabilization control technique based on Koreasat. The payload hardware is combined with CBSSIM via Power, Command and Telemetry System(PCTS) of Electrical Ground Support Equipment(EGSE). CBSSIM is connected with PCTS by TCP/IP and the payload is combined with PCTS by MIL-STD-1553B protocol and DC harness. This simulator runs under the PC-based simulation environment with Windows 2000 operating system. The satellite commands from the operators are transferred to the payload or bus subsystem models through the real-time process block in the simulator. Design requirements of the CBSSIM are to operate in real-time and generate telemetry. CBSSIM provides various graphic monitoring interfaces and control functions and supports both pre-launch and after-launch of a communication satellite system. In this paper, the HITL simulator system including CBSSIM, communications payload and PCTS as the medium of interface between CBSSIM and communications payload will be described in aspects of the system architecture, spacecraft models, and simulator operation environment.
DETERMINATION OF GLOBAL STABILITY OF THE SLOSH MOTION IN A SPACECRAFT VIA NUMERICAL EXPERIMENT
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 351~358
DOI : 10.5140/JASS.2003.20.4.351
The global stability of the attitude motion of a spin-stabilized space vehicle is investigated by performing numerical experiment. In the previous study, a stationary solution and a particular resonant condition for a given model were found by using analytical method but failed to represent the system stability over parameter values near and off the stationary points. Accordingly, as an extension of the previous work, this study performs numerical experiment to investigate the stability of the system across the parameter space and determines stable and unstable regions of the design parameters of the system.
MULTI-SENSOR DATA FUSION FOR FUTURE TELEMATICS APPLICATION
Kim, Seong-Baek ; Lee, Seung-Yong ; Choi, Ji-Hoon ; Choi, Kyung-Ho ; Jang, Byung-Tae ;
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 359~364
DOI : 10.5140/JASS.2003.20.4.359
In this paper, we present multi-sensor data fusion for telematics application. Successful telematics can be realized through the integration of navigation and spatial information. The well-determined acquisition of vehicle's position plays a vital role in application service. The development of GPS is used to provide the navigation data, but the performance is limited in areas where poor satellite visibility environment exists. Hence, multi-sensor fusion including IMU (Inertial Measurement Unit), GPS(Global Positioning System), and DMI (Distance Measurement Indicator) is required to provide the vehicle's position to service provider and driver behind the wheel. The multi-sensor fusion is implemented via algorithm based on Kalman filtering technique. Navigation accuracy can be enhanced using this filtering approach. For the verification of fusion approach, land vehicle test was performed and the results were discussed. Results showed that the horizontal position errors were suppressed around 1 meter level accuracy under simulated non-GPS availability environment. Under normal GPS environment, the horizontal position errors were under 40㎝ in curve trajectory and 27㎝ in linear trajectory, which are definitely depending on vehicular dynamics.
TRACKING CONTROL DESIGN USING SLIDING MODE TECHNIQUES FOR SATELLITE FORMATION FLYING
Lim, Hyung-Chul ; Bang, Hyo-Choong ; Park, Kwan-Dong ; Park, Pil-Ho ;
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 365~374
DOI : 10.5140/JASS.2003.20.4.365
Satellite formation flying is currently an active area of research in the aerospace engineering. So it has been researched by various authors. In this study, a tracking controller using sliding mode techniques was designed to control a satellite for the satellite formation flying. In general, Hill's equations are used to describe the relative motion of the follower satellite with respect to the leader satellite. However the modified Hill's equations considering the
perturbation were used for the design of sliding mode controller. The extended Kalman filter was applied to estimate the state vector based on the measurements of relative distance and velocity between two satellites. The simulation results show that the follower satellite tracks the desired trajectory well by thruster operations based on the sliding mode control law.
A TOOL DEVELOPMENT OF MASS PROPERTIES DATABASE OF A SATELLITE
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 375~382
DOI : 10.5140/JASS.2003.20.4.375
One of the mechanical system engineer's tasks of a satellite design and development is to make the control plan, keep track and estimate the characteristics of system mass properties. As the design phases are go, mass properties related activities also transit as like a data collection, system mass property estimation and measurement. Fidelity of mass properties database should be confirmed through measurement test. In this paper the control plan and estimation of system mass properties are explained by the actual data and experience of the development of satellite and the fidelity of mass properties database was confirmed through measurement test.
ELECTROMAGNETIC COMPATIBILITY DESIGN FOR KOMPSAT-2
Lee, Na-Young ; Lee, Jin-Ho ;
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 383~392
DOI : 10.5140/JASS.2003.20.4.383
It is quite essential that requirements allocation and analysis would be done for the electromagnetic compatibility (EMC) of all units when designing a satellite. Although KOMPSAT-2 inherits relatively large portions of the electrical designs from KOMPSAT-1, it has a new instrument and different combinations of sensors and actuators as well as their driving circuitry. Many requirements for the electromagnetic compatibility were modified and newly allocated for KOMPSAT-2. Naturally, they must be justified through analyses from the early stage of the program. In this paper, the EMC compatibility requirements for KOMPSAT2 are presented and verified for their suitability. In addition, some results, which were obtained from various analyses, are presented and discussed.
SYSTEM TRADE-OFF STUDY AND OPTO-THERMO-MECHANICAL ANALYSIS OF A SUNSHIELD ON THE MSC OF THE KOMPSAT-2
Kim, Young-Soo ; Lee, Eung-Shik ; Woo, Sun-Hee ;
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 393~402
DOI : 10.5140/JASS.2003.20.4.393
The Multi-Spectral Camera (MSC) is the payload of KOMPSAT-2 which is designed for earth imaging in optical and near-infrared region on a sun-synchronous orbit. The telescope in the MSC is a Ritchey-Chretien type with large aperture. The telescope structure should be well stabilized and the optical alignment should be kept steady so that best images can be achieved. However, the MSC is exposed to adverse thermal environment on the orbit which can give impacts on optical performance. Solar incidence can bring non-uniform temperature rise on the telescope tube which entails unfavorable thermal distortion. Three ways of preventing the solar radiation were proposed, which were installing external mechanical shield, internal shield, and maneuvering the spacecraft. After trade-off study, internal sun shield was selected as a practical and optimal solution to minimize the effect of the solar radiation. In addition, detailed designs of the structure and sunshield were produced and analyses have been performed. The results were assessed to verify their impacts to the image quality. It was confirmed that the internal sunshield complies with the requirements and would improve image quality.
SYSTEM ANALYSIS OF PIPELINE SOFTWARE - A CASE STUDY OF THE IMAGING SURVEY AT ESO
Kim, Young-Soo ;
Journal of Astronomy and Space Sciences, volume 20, issue 4, 2003, Pages 403~416
DOI : 10.5140/JASS.2003.20.4.403
There are common features, in both imaging surveys and image processing, between astronomical observations and remote sensing. Handling large amounts of data, in an easy and fast way, has become a common issue. Implementing pipeline software can be a solution to the problem, one which allows the processing of various kinds of data automatically. As a case study, the development of pipeline software for the EIS (European Southern Observatory Imaging Survey) is introduced. The EIS team has been conducting a sky survey to provide candidate targets to the 250 VLTs (Very Large Telescopes) observations. The survey data have been processed in a sequence of five major data corrections and reductions, i.e. preprocessing, flat fielding, photometric and astrometric corrections, source extraction, and coaddition. The processed data are eventually distributed to the users. In order to provide automatic processing of the vast volume of observed data, pipeline software has been developed. Because of the complexity of objects and different characteristic of each process, it was necessary to analyze the whole works of the EIS survey program. The overall tasks of the EIS are identified, and the scheme of the EIS pipeline software is defined. The system structure and the processes are presented, and in-depth flow charts are analyzed. During the analyses, it was revealed that handling the data flow and managing the database are important for the data processing. These analyses may also be applied to many other fields which require image processing.