• Title/Summary/Keyword: Space radiation

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The study on the effect of the solar radiation on thermal comfort and ventilation performance in room space (태양일사가 실내공간의 열적 쾌적성과 환기성능에 미치는 영향에 관한 연구)

  • Yeon, Seong Hyeon;Lee, Hyo Joon;Rhee, Gwang Hoon
    • Journal of the Korean Society of Visualization
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    • v.14 no.1
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    • pp.19-26
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    • 2016
  • Modern people spend much time at indoor space. So, People want to make better indoor air condition. But the facade of building is made of glass to be seen urbanely, the effect of solar radiation makes indoor environment worse. This study designs an open space affected by solar radiation with 4-way cassette air-conditioner. Using numerical simulation, this paper investigates thermal comfort and ventilation performance with discharge angles $30^{\circ}$ and $45^{\circ}$. To study thermal comfort, this paper studies distribution of velocity, temperature and effective draft temperature. Also, this paper introduces concept of air age to study ventilation performance. The flow influenced by solar radiation determines thermal comfort and ventilation performance in room space. This study shows that discharge angle of 45 degree has better thermal comfort and ventilation performance than that of 30 degree.

Long-Term Science Goals with In Situ Observations at the Sun-Earth Lagrange Point L4

  • Dae-Young Lee;Rok-Soon Kim;Kyung-Eun Choi;Jungjoon Seough;Junga Hwang;Dooyoung Choi;Ji-Hyeon Yoo;Seunguk Lee;Sung Jun Noh;Jongho Seon;Kyung-Suk Cho;Kwangsun Ryu;Khan-Hyuk Kim;Jong-Dae Sohn;Jae-Young Kwak;Peter H. Yoon
    • Journal of Astronomy and Space Sciences
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    • v.41 no.1
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    • pp.1-15
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    • 2024
  • The Korean heliospheric community, led by the Korea Astronomy and Space Science Institute (KASI), is currently assessing the viability of deploying a spacecraft at the Sun-Earth Lagrange Point L4 in collaboration with National Aeronautics and Space Administration (NASA). The aim of this mission is to utilize a combination of remote sensing and in situ instruments for comprehensive observations, complementing the capabilities of the L1 and L5 observatories. The paper outlines longterm scientific objectives, underscoring the significance of multi-point in-situ observations to better understand critical heliospheric phenomena. These include coronal mass ejections, magnetic flux ropes, heliospheric current sheets, kinetic waves and instabilities, suprathermal electrons and solar energetic particle events, as well as remote detection of solar radiation phenomena. Furthermore, the mission's significance in advancing space weather prediction and space radiation exposure assessment models through the integration of L4 observations is discussed. This article is concluded with an emphasis on the potential of L4 observations to propel advancements in heliospheric science.

THE ANALYSIS ON SPACE RADIATION ENVIRONMENT AND EFFECT OF THE KOMPSAT-2 SPACECRAFT(I): TOTAL IONIZING DOSE EFFECT (아리랑 2호의 방사능 환경 및 영향에 관한 분석(I)- TOTAL IONIZING DOSE 영향 중심으로 -)

  • 백명진;김학정
    • Journal of Astronomy and Space Sciences
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    • v.18 no.2
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    • pp.153-162
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    • 2001
  • In this paper, space radiation environment and total ionizing dose(TID) effect have been analyzed for the KOMPSAT-2 operational orbit. It has been revealed that the trapped protons are concentrated in the SAA(South Atlantic Anomaly) area and that the trapped protons and electrons, and solar protons are main factors affecting TID. It turned out that low energy Particles can be effectively blocked by aluminum shielding thickness, but high energy Particles can not be effectively blocked by increasing aluminum shielding thickness. KOMPSAT-2 total radiation dose which is accumulated continuously to spacecraft electronics has been expressed as the function of aluminum thickness. These values ran be used as the criteria for the selection of electronic parts and shielding thinkness of the KOMPSAT-2 structure or electronic box.

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Incorporation of Electromagnetic Ion cyclotron waveinto Radiation Belt environment model

  • Kang, Suk-Bin;Choi, Eunjin;Hwang, Junga;Kim, Kyung-Chan;Lee, Jaejin;Fok, Mei-ching;Min, Kyoungwook;Choi, Cheongrim;Park, Young-Deuk
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.132.1-132.1
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    • 2012
  • Radiation Belt Environment (RBE) model has developed to understand radiation belt dynamics as it considers whistler mode hiss and chorus waves which is responsible for relativistic electron acceleration and precipitation. Recently, many studies on electron loss by pitch-angle scattering have reported that elctromagnetic ion cyclotron (EMIC) wave is also responsible for main loss mechanism in dusk and equatorial regeion. Here, we attempt to incorporate EMIC into RBE model simulation code to understand more detailed physical dynamics in Radiation belt environemnt. We compare this developed model to data during storm events where both of electron loss and EMIC waves were detected.

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PRELAUNCH THERMAL ANALYSIS OF KSLV-I PAYLOAD FAIRING

  • Choi Sang-Ho;Kim Seong-Lyong;Kim Insun
    • Bulletin of the Korean Space Science Society
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    • 2004.10b
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    • pp.356-359
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    • 2004
  • Prelaunch thermal analysis of the KSLV (Korea Space Launch Vehicle)-I PLF (Payload Fairing) was performed to predict maximum/minimum liftoff temperatures and to evaluate of air conditioning performance. Prelaunch thermal analysis includes internal air conditioning effect, external convective heating/cooling, radiation exchange with the ground and sky, radiation between spacecraft and PLF, and solar radiation incident on PLF. Analysis was performed at two extreme conditions, hot day condition and cold day condition. The results showed that the maximum liftoff temperature was $53^{\circ}C$ and the minimum liftoff temperature was $-3.8^{\circ}C$. It was also found that conditioned air supplying, in $20{\pm}2^{\circ}C\;and\;1200\;m^3/hr$, is sufficient to keep the internal air in required temperature range.

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Particle capture by radiation drag around a highly luminous compact stars

  • Oh, Jae Sok;Park, Chan;Kim, Hongsu
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.1
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    • pp.77.2-77.2
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    • 2013
  • xIn the present work, we explored the effect of the radiation on the effective impact parameter for capture in a fully general relativistic manner. To summarize our results, evidently due to the radiation drag (the Poynting-Robertson effect), critical impact parameter of point particle gets larger by the factor of two, thus, the effective cross section of the luminous relativistic star becomes 4 times larger than that of the star without radiation emission. In addition, the finite size effect of the star adds up to this growth of the effective cross section.

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Latest Research Trends on Space Environments in Korea

  • Eojin Kim;Seongsuk Lee;Bogyeong Kim
    • Journal of Space Technology and Applications
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    • v.3 no.4
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    • pp.301-321
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    • 2023
  • The Journal of Astronomy and Space Sciences (JASS) has published research papers on a range of topics since its initial publication in 1984, giving space science researchers a platform. In this paper, we reviewed recent publications (2019-2023) that deal with the space environment. In the space environment field, we reviewed 37 papers published in JASS during this time, covering research topics such as the sun, magnetosphere, ionosphere, atmosphere, and space radiation. We hope that researchers in the field will make use of this in the future as it will allow us to share the most recent trends in the field of space environment research that is currently underway.

Radiation Effects on the Power MOSFET for Space Applications

  • Lho, Young-Hwan;Kim, Ki-Yup
    • ETRI Journal
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    • v.27 no.4
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    • pp.449-452
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    • 2005
  • The electrical characteristics of solid state devices such as the bipolar junction transistor (BJT), metal-oxide semiconductor field-effect transistor (MOSFET), and other active devices are altered by impinging photon radiation and temperature in the space environment. In this paper, the threshold voltage, the breakdown voltage, and the on-resistance for two kinds of MOSFETs (200 V and 100 V of $V_{DSS}$) are tested for ${\gamma}-irradiation$ and compared with the electrical specifications under the pre- and post-irradiation low dose rates of 4.97 and 9.55 rad/s as well as at a maximum total dose of 30 krad. In our experiment, the ${\gamma}-radiation$ facility using a low dose, available at Korea Atomic Energy Research Institute (KAERI), has been applied on two commercially available International Rectifier (IR) products, IRFP250 and IRF540.

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Satellite Anomalies due to Spce Environment Events (우주환경 이벤트에 의한 위성의 이상현상)

  • Park, Jae-Woo;Jeong, Cheol-Oh
    • Journal of Satellite, Information and Communications
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    • v.6 no.2
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    • pp.102-106
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    • 2011
  • Space Environment including Solar activities such as Solar explosion, Corona Mass Ejection(CMS) is always not friendly for human. Especially it may be fatal to artificial satellites. The lifetime of geostationary communication satellites are reducing due to plasma such as electrons, protons etc. emitting from Sun. This is because the active components constituting communication satellite are easily affected by plasma. Even though the radiation shielding on the components can be a way to prevent, the cost will be high. So the appropriate shielding is necessary and the study on space environment is also. In this study spacecraft anomalies will be investigated from low earth orbit to deep space spacecraft and the correlation between spacecraft anomalies and space environment events including space explosion, geomagnetic storms etc is analyzed.

COASTAL ENVIRONMENT MONITORING USING ADJACENT EFFECT OF RADIATION

  • Takashima, Tsutomu;Jung, Sung-Chul;Yi, San-Oh;Kim, Tu-Hwan
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.430-431
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    • 2006
  • KOMPSAT-2 was successively launched on July 28,06. She carries Fine Spatial Resolution Sensor with three channels. It is 4m monochromatic and 1m panchromatic. The main purposes would derive fine urban map and digital elevation model(DEM).Therefore we extend to coastal environment monitoring using the adjacent effect of radiation due to an interaction of radiation between heterogeneous surface and atmosphere. With data analysis of ASTER on TERA, which is 15m resolution in visible and near infrared wavelengths, we found atmospheric aerosols were always large. Note that data analysis was limited in Nagoya bay, Lake Tahoe, California & La Pozuelos, La Picasa, Argentina. Thus this time we expect data analyses around isolated island and peninsula in west and south coast of Korea.

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