데이모스 2호의 우주 궤도에서의 총 이온화 방사선량 해석

김영석,김주나,정연황 한국항공우주학회 2014 한국항공우주학회 학술발표회 논문집 Vol.2014 No.11

지구관측 저궤도 소형위성인 Space Eye-1 플랫폼을 기반으로 한 데이모스-2 호 위성이 겪게 될 우주방사선 환경을 TID 관점에서 분석하였다. 우주에는 다양한 방사선 입자들이 존재하며, 특히 방사선 벨트에 포획된 입자들이 저궤도 위성에 많은 영향을 미친다. 이러한 포획된 전자 및 양성자, 태양양성자의 영향을 분석하기 위해 NASA 의 AP8, AE8 및 ESP-PSYCHIC 모델을 사용하여 개별 입자의 선속 분포를 모사하였다. 또한 총 이온화 방사선량(TID) 환경이 전자 소자에 미치는 영향을 추정하기 위해 Dose-Depth 곡선을 구하였고, 분할 차폐물 해석을 통하여 위성의 구조물과 전장박스의 차폐효과를 고려한 주요 PCB 의 총 이온화 방사선량 영향을 분석하였다. 이를 기반으로 데이모스-2 호가 TID 환경하에서 설계 수명을 견딜 수 있는지 분석하였다. Deimos-2 is a small earth observation satellite based on the Space Eye-1 platform of Satrec Initiative. The Space radiation environment in the view point of total ionizing dose(TID) is simulated by NASA AP-8, AE-8 and ESPPSYCHIC model for trapped electron, trapped proton and solar particle fluences respectively. Dose-depth curve in accordance with the shielding thickness is calculated to estimate the TID effect on the satellite EEE components. Using the dose depth curve and satellite shielding thickness data from the detailed satellite 3-D model, the TID level of interesting points are calculated and compared with their component rated TID level, to check that the Deimos-2 satellite can withstand the design lifetime in the space TID environment.

Analysis of the charged particle radiation effect for a CubeSat transiting from Earth to Mars

Yoon, S.,Shin, Y.,Jeon, J.,Seo, Y.,Jeon, J.,Woo, J.,Seon, J. Elsevier 2014 CURRENT APPLIED PHYSICS Vol.14 No.4

This paper presents a computational estimation of the total ionizing dose from protons and electrons in the Earth's magnetosphere and interplanetary space for a hypothetical CubeSat transiting from Earth to Mars. An initial hyperbolic escape of the spacecraft from Earth's gravitation is assumed, followed by an elliptical transfer from Earth to Mars under the Sun's gravitation. The rapid traversal of the Earth's radiation belt yields a smaller ionizing dose, whereas high-energy solar protons in the interplanetary space have the greatest effect on the ionizing dose during the transfer between the planets. Variation in the heliocentric distance of the spacecraft is considered in the calculation. Calculation of the shielding distributions with Geant4 and the transport of the ionizing particles across the obtained distributions yields an estimation of the total ionizing dose as a function of position within the spacecraft as well as statistical confidence levels. With a moderate confidence level, this calculation shows that a practical exploration of Mars with a CubeSat is possible in terms of the expected total ionizing dose.

Analysis of the charged particle radiation effect for a CubeSat transiting from Earth to Mars

윤세영,신유철,전제헌,서용명,전종호,우주,선종호 한국물리학회 2014 Current Applied Physics Vol.14 No.4

This paper presents a computational estimation of the total ionizing dose from protons and electrons in the Earth’s magnetosphere and interplanetary space for a hypothetical CubeSat transiting from Earth to Mars. An initial hyperbolic escape of the spacecraft from Earth’s gravitation is assumed, followed by an elliptical transfer from Earth to Mars under the Sun’s gravitation. The rapid traversal of the Earth’s radiation belt yields a smaller ionizing dose, whereas high-energy solar protons in the interplanetary space have the greatest effect on the ionizing dose during the transfer between the planets. Variation in the heliocentric distance of the spacecraft is considered in the calculation. Calculation of the shielding distributions with Geant4 and the transport of the ionizing particles across the obtained distributions yields an estimation of the total ionizing dose as a function of position within the spacecraft as well as statistical confidence levels. With a moderate confidence level, this calculation shows that a practical exploration of Mars with a CubeSat is possible in terms of the expected total ionizing dose.

Space Radiation Shielding Calculation by Approximate Model for LEO Satellites

Shin Myung-Won,Kim Myung-Hyun Korean Nuclear Society 2004 Nuclear Engineering and Technology Vol.36 No.1

Two approximate methods for a cosmic radiation shielding calculation in low earth orbits were developed and assessed. Those are a sectoring method and a chord-length distribution method. In order to simulate a change in cosmic radiation environments along the satellite mission trajectory, IGRF model and AP(E)-8 model were used. When the approximate methods were applied, the geometrical model of satellite structure was approximated as one-dimensional slabs, and a pre-calculated dose-depth conversion function was introduced to simplify the dose calculation process. Verification was performed with mission data of KITSAT-1 and the calculated results were also compared with detailed 3-dimensional calculation results using Monte Carlo calculation. Dose results from the approximate methods were conservatively higher than Monte Carlo results, but were lower than experimental data in total dose rate. Differences between calculation and experimental data seem to come from the AP-8 model, for which it is reported that fluxes of proton are underestimated. We confirmed that the developed approximate method can be applied to commercial satellite shielding calculations. It is also found that commercial products of semi-conductors can be damaged due to total ionizing dose under LEO radiation environment. An intensive shielding analysis should be taken into account when commercial devices are used.

Cumulative ionizing effect from solar-terrestrial charged particles and cosmic rays for CubeSats as simulated with GEANT4

Y.M SEO,Y.H. KIM,S.H. PARK,J. SEON 한국물리학회 2012 Current Applied Physics Vol.12 No.6

Computational results for the cumulative effect of ionizing radiation are presented for CubeSats taking into account the presence of trapped charged particles in the Earth’s magnetosphere, protons and heavy ions from the Sun, and the cosmic rays. In contrast to relatively larger satellites, CubeSats are often launched with minimal shielding structures. Therefore, detailed modeling of a CubeSat is performed based on currently available standard platforms. The geometrical modeling is then used for an estimation of the ionizing doses for various locations within the CubeSat spacecraft operating at low altitudes. The calculation is reiterated and extended for more exotic orbits, such as geostationary Earth orbits and lunar orbits, for the potential application of CubeSats in challenging space missions.

Cumulative ionizing effect from solar-terrestrial charged particles and cosmic rays for CubeSats as simulated with GEANT4

Seo, Y.M.,Kim, Y.H.,Park, S.H.,Seon, J. Elsevier 2012 CURRENT APPLIED PHYSICS Vol.12 No.6

Computational results for the cumulative effect of ionizing radiation are presented for CubeSats taking into account the presence of trapped charged particles in the Earth's magnetosphere, protons and heavy ions from the Sun, and the cosmic rays. In contrast to relatively larger satellites, CubeSats are often launched with minimal shielding structures. Therefore, detailed modeling of a CubeSat is performed based on currently available standard platforms. The geometrical modeling is then used for an estimation of the ionizing doses for various locations within the CubeSat spacecraft operating at low altitudes. The calculation is reiterated and extended for more exotic orbits, such as geostationary Earth orbits and lunar orbits, for the potential application of CubeSats in challenging space missions.

TID Effect Test of the ICS307GI-03LF Serially Programmable Clock Source for Space Applications

신구환,류광선,명로훈,김이을 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.22

The ICS307GI-03LF is a dynamic, serially programmable clock source that is flexible and takes up minimal board space and whose output frequencies are programmed via a serial interface port. The device can be programmed during operation, making it ideal for applications where many different frequencies are required. To apply it to space parts, we have performed a total ionizing dose (TID) test for the ICS307GI-03LF serially programmable clock source by using a low-level γ irradiator with <SUP>60</SUP>Co γ-ray sources at the ARTI (Advanced Radiation Technology Institute), which belongs to the KAERI (Korea Atomic Energy Research Institute). The irradiation with gamma-rays was carried out at doses from 0 krad to 100 krad to check the status of the device in terms of frequency and current. In this paper, we report on the TID test results for the ICS307GI-03LF clock source.

초소형 위성의 총 이온화 선량 계산

서용명,김용호,박성하,채규성,진호,이동훈,선종호 한국항공우주학회 2012 한국항공우주학회 학술발표회 논문집 Vol.2012 No.4

태양-지구간 대전 입자들이 위성 내부에 누적되어 발생하는 총 이온화 선량 계산을 초소형 위성 큐브셋(CubeSat)을 대상으로 수행하였다. 본 연구에서는 표준화된 규격에 의해 유사한 차폐두께 및 분포를 갖는 큐브셋의 특징을 주목하여, 위성의 운용이 유력한 지구 저궤도, 정지궤도 천이궤도, 지구 정지궤도, 달 천이궤도의 대전 입자 환경을 고려하여 계산을 수행하였다. 계산을 위해 표준 규격을 따르는 간소화된 구조체를 설계하여 해석에 사용하였으며, 위성 내 전자부품의 배치가 유력한 위치들을 선정하여 특정 위치에 누적되는 방사선량을 도출하였다. 계산결과로서 지구 저궤도는 총 이온화 선량의 영향에 대해 안전한 임무궤도임을 알 수 있었으며, 정지궤도와 정지궤도 천이궤도는 큐브셋의 운용이 열악한 선량 값이 도출되었다. Computational results for the cumulative effect of ionizing radiation is presented for CubeSats taking into account the presence of the charged particles in the vicinity of the Earth. Detailed modeling of CubeSat is performed based on currently available standard platforms. The geometrical modeling is then used for estimation of the ionizing doses for various locations within the spacecraft operating at low altitudes. The calculation is reiterated and extended for more exotic orbits such as geostationary Earth orbits and lunar orbits for potential application of CubeSats in challenging space missions.

Radiation Analysis of Communications and Broadcasting Satellite

Park, Jae-Woo,Chung, Tae-Jin,Lee, Seong-Pal,Seon, Jong-Ho,Jeong, Yun-Whang The Korean Society for Aeronautical and Space Scie 2002 International Journal of Aeronautical and Space Sc Vol.3 No.2

A radiation analysis is performed for the Ka and Ku-band transponder of the Communications and Broadcasting Satellite (CBS) that is planned for launch into the geo-synchronous orbit. A particular attention is given to calculation of Total Ionizing Dose (TID) for the mission life time of 15 + 3 years. A numerical modeling of the charged particles at the geo-synchronous orbit is undertaken. The charged particles from the modeling are then transported through the mechanical structure and component housings of the transponder. A set of locations are selected for the detailed calculation of TID. The results from the present calculation show that three-dimensional modeling of the component housings as well as the mechanical structure of the spacecraft is requisite in order to acquire a reliable calculation of TID.

Relation between the Enhanced Low-Dose-Rate Effects of Metal Oxide Semiconductors and the Vacant Oxide Trap Densities of SiO2

D. H. Ko,S. W. Rhee,S. J. Kim,민경욱 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.2

The relations between the enhanced low-dose-rate Effects (ELDREs) of radiation-sensitive field ef- fect transistors (RADFETs) developed by the National Micro-electronics Research Centre (NMRC) and the vacant oxide trap densities in SiO2 were found. The ELDREs of the NMRC RADFETs occured only when the vacant oxide trap density was high. To ensure these relations, we found the distribution of radiation-induced electron-hole pairs in SiO2 by using a MCNPX(Monte Carlo N-Particle eXtended) simulation and we performed other radiation tests for the NMRC RADFETs and for the commercial 3N163 FETs developed by Linear Systems. With the above results, we also present some possible reasons previous research could not find the ELDREs.