Journal of Astronomy and Space Sciences最新文献

{"title":"A Study of Dark Photon at the Electron-Positron Collider Experiments Using KISTI-5\u0000 Supercomputer","authors":"Kihong Park, Kihyeon Cho","doi":"10.5140/JASS.2021.38.1.55","DOIUrl":"https://doi.org/10.5140/JASS.2021.38.1.55","url":null,"abstract":"The universe is well known to be consists of dark energy, dark matter and the\u0000 standard model (SM) particles. The dark matter dominates the density of matter in the\u0000 universe. The dark matter is thought to be linked with dark photon which are\u0000 hypothetical hidden sector particles similar to photons in electromagnetism but\u0000 potentially proposed as force carriers. Due to the extremely small cross-section of dark\u0000 matter, a large amount of data is needed to be processed. Therefore, we need to optimize\u0000 the central processing unit (CPU) time. In this work, using MadGraph5 as a simulation\u0000 tool kit, we examined the CPU time, and cross-section of dark matter at the\u0000 electron-positron collider considering three parameters including the center of mass\u0000 energy, dark photon mass, and coupling constant. The signal process pertained to a dark\u0000 photon, which couples only to heavy leptons. We only dealt with the case of dark photon\u0000 decaying into two muons. We used the simplified model which covers dark matter particles\u0000 and dark photon particles as well as the SM particles. To compare the CPU time of\u0000 simulation, one or more cores of the KISTI-5 supercomputer of Nurion Knights Landing and\u0000 Skylake and a local Linux machine were used. Our results can help optimize high-energy\u0000 physics software through high-performance computing and enable the users to incorporate\u0000 parallel processing.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"13 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87599523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Substorm Injection Event and the Radiation Belt Structure Observed by Space\u0000 Radiation Detectors onboard Next Generation Small Satellite-1 (NEXTSat-1)","authors":"Ji-Hyeon Yoo, Dae‐Young Lee, Eojin Kim, H. Seo, Kwang-Sun Ryu, Kyung‐Chan Kim, K. Min, J. Sohn, Junchan Lee, J. Seon, K. Kang, Seunguk Lee, Jaeheung Park, G. Shin, Sung-Og Park","doi":"10.5140/JASS.2021.38.1.31","DOIUrl":"https://doi.org/10.5140/JASS.2021.38.1.31","url":null,"abstract":"In this paper, we present observations of the Space Radiation Detectors (SRDs)\u0000 onboard the Next Generation Small Satellite-1 (NEXTSat-1) satellite. The SRDs, which are\u0000 a part of the Instruments for the study of Stable/Storm-time Space (ISSS), consist of\u0000 the Medium-Energy Particle Detector (MEPD) and the High-Energy Particle Detector (HEPD).\u0000 The MEPD can detect electrons, ions, and neutrals with energies ranging from 20 to 400\u0000 keV, and the HEPD can detect electrons over an energy range from 0.35 to 2 MeV. In this\u0000 paper, we report an event where particle flux enhancements due to substorm injections\u0000 are clearly identified in the MEPD A observations at energies of tens of keV.\u0000 Additionally, we report a specific example observation of the electron distributions\u0000 over a wide energy range in which we identify electron spatial distributions with\u0000 energies of tens to hundreds of keV from the MEPD and with energy ranging up to a few\u0000 MeV from the HEPD in the slot region and outer radiation belts. In addition, for an\u0000 ~1.5-year period, we confirm that the HEPD successfully observed the well-known outer\u0000 radiation belt electron flux distributions and their variations in time and L shell in a\u0000 way consistent with the geomagnetic disturbance levels. Last, we find that the inner\u0000 edge of the outer radiation belt is mostly coincident with the plasmapause locations in\u0000 L, somewhat more consistent at subrelativistic energies than at relativistic energies.\u0000 Based on these example events, we conclude that the SRD observations are of reliable\u0000 quality, so they are useful for understanding the dynamics of the inner magnetosphere,\u0000 including substorms and radiation belt variations.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"74 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82718172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spin Axis Determination of Defunct GLONASS Satellites Using Photometry\u0000 Observation","authors":"Jee-Ho Lee, E. Park, Mansoo Choi, D. Kucharski, Y. Yi, J. Park","doi":"10.5140/JASS.2021.38.1.45","DOIUrl":"https://doi.org/10.5140/JASS.2021.38.1.45","url":null,"abstract":"GLONASS, a satellite navigation system developed in Russia since 1976, is defunct\u0000 and orbits in an unstable attitude. The satellites in these problems are not managed and\u0000 there is no precise information, which can increase the risk of collisions with other\u0000 space objects. In this study, detailed attitude dynamic have to be analyzed through\u0000 photometry data, which requires spin period and spin axis. The light curve data is\u0000 obtained by observing through the photometer at the Graz station and the power spectrum\u0000 is calculated to obtain the cycle of the satellite. The geometric relationship between\u0000 observer and sun is analyzed for GLONASS-50 satellite. The box-wing model is applied to\u0000 obtain the phase reflection of the satellite and obtain the Irradiation of the satellite\u0000 through this information. In Light Curve and Irradiation, the spin axis is calculated\u0000 for each peak points with the distance square minimum technique. The spin axis of the\u0000 GLONASS-50 satellite is RA = 116°, Dec = 92°.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"6 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84431677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geostationary Satellite Station Keeping Robustness to Loss of Ground\u0000 Control","authors":"Hyung-Je Woo, Björn Buckwalter","doi":"10.5140/JASS.2021.38.1.65","DOIUrl":"https://doi.org/10.5140/JASS.2021.38.1.65","url":null,"abstract":"For the vast majority of geostationary satellites currently in orbit, station\u0000 keeping activities including orbit determination and maneuver planning and execution are\u0000 ground-directed and dependent on the availability of ground-based satellite control\u0000 personnel and facilities. However, a requirement linked to satellite autonomy and\u0000 survivability in cases of interrupted ground support is often one of the stipulated\u0000 provisions on the satellite platform design. It is especially important for a\u0000 geostationary military-purposed satellite to remain within its designated orbital\u0000 window, in order to provide reliable uninterrupted telecommunications services, in the\u0000 absence of ground-based resources due to warfare or other disasters. In this paper we\u0000 investigate factors affecting the robustness of a geostationary satellite’s orbit in\u0000 terms of the maximum duration the satellite’s station keeping window can be maintained\u0000 without ground intervention. By comparing simulations of orbit evolution, given\u0000 different initial conditions and operations strategies, a variation of parameters study\u0000 has been performed and we have analyzed which factors the duration is most sensitive to.\u0000 This also provides valuable insights into which factors may be worth controlling by a\u0000 military or civilian geostationary satellite operator. Our simulations show that the\u0000 most beneficial factor for maximizing the time a satellite will remain in the station\u0000 keeping window is the operational practice of pre-emptively loading East-West station\u0000 keeping maneuvers for automatic execution on board the satellite should ground control\u0000 capability be lost. The second most beneficial factor is using short station keeping\u0000 maneuver cycle durations.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"114 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88812368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance Analysis of M-ary Optical Communication over Log-Normal Fading Channels\u0000 for CubeSat Platforms","authors":"H. Lim, Sung-Yeol Yu, Ki-Pyoung Sung, J. Park, C. Choi, Mansoo Choi","doi":"10.5140/JASS.2020.37.4.219","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.4.219","url":null,"abstract":"A CubeSat platform has become a popular choice due to inexpensive commercial\u0000 off-the-shelf (COTS) components and low launch cost. However, it requires more\u0000 power-efficient and higher-data rate downlink capability for space applications related\u0000 to remote sensing. In addition, the platform is limited by the size, weight and power\u0000 (SWaP) constraints as well as the regulatory issue of licensing the radio frequency (RF)\u0000 spectrum. The requirements and limitations have put optical communications on promising\u0000 alternatives to RF communications for a CubeSat platform, owing to the power efficiency\u0000 and high data rate as well as the license free spectrum. In this study, we analyzed the\u0000 performance of optical downlink communications compatible with CubeSat platforms in\u0000 terms of data rate, bit error rate (BER) and outage probability. Mathematical models of\u0000 BER and outage probability were derived based on not only the log-normal model of\u0000 atmospheric turbulence but also a transmitter with a finite extinction ratio. Given the\u0000 fixed slot width, the optimal guard time and modulation orders were chosen to achieve\u0000 the target data rate. And the two performance metrics, BER and outage data rate, were\u0000 analyzed and discussed with respect to beam divergence angle, scintillation index and\u0000 zenith angle.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"4 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88520557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preliminary Results of Tissue-Equivalent Proportional Counter (TEPC) Dosimeter for\u0000 Measuring In-Situ Aviation Radiation","authors":"U. Nam, W. Park, Jung-Lae Hwang, J. Sohn, B. Moon, Sunghwan Kim","doi":"10.5140/JASS.2020.37.4.249","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.4.249","url":null,"abstract":"We develop the tissue-equivalent proportional counter (TEPC) type’s space\u0000 radiation dosimeter to measure in-situ aviation radiation. That was originally developed\u0000 as a payload of small satellite in the low-earth orbit. This dosimeter is based on a\u0000 TEPC. It is made of an A-150 tissue-equivalent plastic shell of an internal diameter of\u0000 6 cm and a thickness of 0.3 cm. TEPC is filled with pure propane at 13.9 torrs to\u0000 simulate a cell diameter of 2 μm. And the associated portable and low power electronics\u0000 are also implemented. The verification experiments have been performed by the\u0000 calibration experiments at ground level and compared with Liulin observation at aircraft\u0000 altitude during the flight between Incheon airport (ICN) and John F. Kennedy airport\u0000 (JFK). We found that the TEPC dosimeter can be used as a monitor for space radiation\u0000 dosimeter at aviation altitude based on the verification with Liulin observation.\u0000","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"91 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83720606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ground Tracking Support Condition Effect on Orbit Determination for Korea\u0000 Pathfinder Lunar Orbiter (KPLO) in Lunar Orbit","authors":"Young-Rok Kim, Young-Joo Song, Jae-ik Park, Donghun Lee, Jonghee Bae, Seung-Su Hong, Dae-Kwan Kim, Sang-Ryool Lee","doi":"10.5140/JASS.2020.37.4.237","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.4.237","url":null,"abstract":"The ground tracking support is a critical factor for the navigation performance\u0000 of spacecraft orbiting around the Moon. Because of the tracking limit of antennas, only\u0000 a small number of facilities can support lunar missions. Therefore, case studies for\u0000 various ground tracking support conditions are needed for lunar missions on the stage of\u0000 preliminary mission analysis. This study analyzes the ground supporting condition effect\u0000 on orbit determination (OD) of Korea Pathfinder Lunar Orbiter (KPLO) in the lunar orbit.\u0000 For the assumption of ground support conditions, daily tracking frequency, cut-off angle\u0000 for low elevation, tracking measurement accuracy, and tracking failure situations were\u0000 considered. Two antennas of deep space network (DSN) and Korea Deep Space Antenna (KDSA)\u0000 are utilized for various tracking conditions configuration. For the investigation of the\u0000 daily tracking frequency effect, three cases (full support, DSN 4 pass/day and KDSA 4\u0000 pass/day, and DSN 2 pass/day and KDSA 2 pass/day) are prepared. For the elevation\u0000 cut-off angle effect, two situations, which are 5 deg and 10 deg, are assumed. Three\u0000 cases (0%, 30%, and 50% of degradation) were considered for the tracking measurement\u0000 accuracy effect. Three cases such as no missing, 1-day KDSA missing, and 2-day KDSA\u0000 missing are assumed for tracking failure effect. For OD, a sequential estimation\u0000 algorithm was used, and for the OD performance evaluation, position uncertainty,\u0000 position differences between true and estimated orbits, and orbit overlap precision\u0000 according to various ground supporting conditions were investigated. Orbit prediction\u0000 accuracy variations due to ground tracking conditions were also demonstrated. This study\u0000 provides a guideline for selecting ground tracking support levels and preparing a backup\u0000 plan for the KPLO lunar mission phase.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"45 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77630701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation of KREAM Based on In-Situ Measurements of Aviation Radiation in\u0000 Commercial Flights","authors":"Jung-Lae Hwang, Jaeyoung Kwak, Gyeongbok Jo, U. Nam","doi":"10.5140/JASS.2020.37.4.229","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.4.229","url":null,"abstract":"There has been increasing necessity of more precise prediction and measurements\u0000 of aviation radiation in Korea. For our air crew and passengers’ radiation safety, we\u0000 develop our own radiation prediction model of KREAM. In this paper, we validate the\u0000 KREAM model based on comparison with Liulin observations. During early three months of\u0000 this year, we perform total 25 experiments to measure aviation radiation exposure using\u0000 Liulin-6K in commercial flights. We found that KREAM’s result is very well consistent\u0000 with Liulin observation in general. NAIRAS shows mostly higher results than Liulin\u0000 observation, while CARI-6M shows generally lower results than the observations. The\u0000 percent error of KREAM compared with Liulin observation is 10.95%. In contrast, the\u0000 error for NAIRAS is 43.38% and 22.03% for CARI-6M. We found that the increase of the\u0000 altitude might cause sudden increase in radiation exposure, especially for the polar\u0000 route. As more comprehensive and complete analysis is required to validate KREAM’s\u0000 reliability to use for the public service, we plan to expand these radiation\u0000 measurements with Liulin and Tissue Equivalent Proportional Counter (TEPC) in the near\u0000 future.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"36 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77286142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal Variation of Cosmic Ray Intensity Observed by the Oulu Neutron\u0000 Monitor","authors":"Jaesik Jeong, Suyeon Oh","doi":"10.5140/JASS.2020.37.3.165","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.3.165","url":null,"abstract":"Muons and neutrons are representative secondary particles that are generated by\u0000 interactions between primary cosmic ray particles (mostly protons) and the nuclei of\u0000 atmospheric gas compounds. Previous studies reported that muons experience seasonal\u0000 variations because of the meteorological effects of temperature. The intensity of\u0000 neutrons has a typical modulation with various periods and reasons, such as diurnal and\u0000 solar variation or transient events. This paper reports that cosmic ray particles, which\u0000 were observed by neutron monitors, have seasonal variations using the daily data at the\u0000 Oulu neutron monitor. To eliminate the effects of solar activity across time, the daily\u0000 data were normalized by two different transformations: transformations with respect to\u0000 the grand mean and yearly mean. The data after transformation with respect to the yearly\u0000 mean showed more statistical stability and clear seasonal variations. On the other hand,\u0000 it is difficult to determine if the seasonal variation results from terrestrial effects,\u0000 such as meteorological factors, or extraterrestrial effects, such as the position of the\u0000 Earth in its orbit of revolution.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"65 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86054778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Initial Operation and Preliminary Results of the Instrument for the Study of\u0000 Stable/Storm-Time Space (ISSS) on Board the Next Generation Small Satellite-1\u0000 (NEXTSat-1)","authors":"Eojin Kim, Ji-Hyeon Yoo, Hee-Eun Kim, H. Seo, K. Ryu, J. Sohn, Junchan Lee, J. Seon, Ensang Lee, Dae‐Young Lee, K. Min, K. Kang, Sang-Yun Lee, Juneseok Kang","doi":"10.5140/JASS.2020.37.3.209","DOIUrl":"https://doi.org/10.5140/JASS.2020.37.3.209","url":null,"abstract":"This paper describes the initial operations and preliminary results of the\u0000 Instrument for the study of Stable/Storm-time Space (ISSS) onboard the microsatellite\u0000 Next Generation Small Satellite-1 (NEXTSat-1), which was launched on December 4, 2018\u0000 into a sun-synchronous orbit at an altitude of 575 km with an orbital inclination angle\u0000 of 97.7°. The spacecraft and the instruments have been working normally, and the results\u0000 from the observations are in agreement with those from other satellites. Nevertheless,\u0000 improvement in both the spacecraft/instrument operation and the analysis is suggested to\u0000 produce more fruitful scientific results from the satellite operations. It is expected\u0000 that the ISSS observations will become the main mission of the NEXTSat-1 at the end of\u0000 2020, when the technological experiments and astronomical observations terminate after\u0000 two years of operation.","PeriodicalId":44366,"journal":{"name":"Journal of Astronomy and Space Sciences","volume":"21 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90839741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}