Jong-Ho Seon

Numerical solutions to the stable, space-charge-limited emission of secondary electrons from plasmawall interaction are found based on one-dimensional plasma moment equations that assume cold ions, Maxwellian electrons and cold secondary electrons. The numerical method finds a range of plasma parameters that permit stable emission of secondary electrons in the absence of normal electric fields to the wall. These solutions were not obtained with previous method that solves only for the marginally

The solar proton telescope (SPT) is considered as one of the scientific instruments to be installed in instruments for the study of space storm (ISSS) which is determined for next generation small satellite-1 (NEXTSat-1). The SPT is the instrument that acquires the information on energetic particles, especially the energy and flux of proton, according to the solar activity in the space radiation environment. We performed the simulation to determine the specification of the SPT using geometry and

A package of space science instruments, dubbed the Instruments for the Study of Space Storms (ISSS), is proposed for the NextGeneration Small Satellite-1 (NEXTSat-1), which is scheduled for launch in May 2016. This paper describes the instrumentdesigns and science missions of the ISSS. The ISSS configuration in NEXTSat-1 is as follows: the space radiation monitoringinstruments consist of medium energy particle detector (MEPD) and high energy particle detector (HEPD); the space plasmainstruments

Thermal analysis and control design are prerequisite essential to design the satellite. In the space environment, it makes satellite survive from extreme hot and cold conditions. In recent years CubeSat mission is developed for many kinds of purpose. Triplet Ionospheric Observatory (TRIO)–CubeSat for Ion, Neutral, Electron, MAgnetic fields (CINEMA) is required to weigh less than 3 kg and operate on minimal 3 W power. In this paper we describe the thermal analysis and control design for TRIO-CINE

A computational method for predicting and analyzing the cumulative effect of ionizing radiation in space is presented, taking into account the presence of the charged particles from the Sun and Earth together with the cosmic rays precipitating toward the vicinity of Earth. The method first integrates the population of charged particles along the trajectories of the instrument in space, and then transports the charged particles across the shielding material. A novel method of interfacing a sophis

A numerical method is proposed to calculate the response of detectors measuring particle energies from incident isotropic fluxes of electrons and positive ions. The isotropic flux is generated by injecting particles moving radially inward on a hypothetical, spherical surface encompassing the detectors. A geometric projection of the field-of-view from the detectors onto the spherical surface allows for the identification of initial positions and momenta corresponding to the clear field-of-view of

In this study, we investigated the effect of space plasmas on the floating potential variation of a low-altitude, polar-orbitingsatellite using the Langmuir Probe (LP) measurement onboard the STSAT-1 spacecraft. We focused on small potential drops,for which the estimation of plasma density and temperature from LP is available. The floating potential varied accordingto the variations of plasma density and temperature, similar to the previously reported observations. Most of the potentialdrops occ

양성자 가속기를 이용한 지상 실험에 기초하여 인공위성에서 사용할 마이크로프로세서 의 SEE 발생률을 예측하였다. 우주 공간의 하전 입자 분포를 AP8, JPL91 그리고 CREME 모델을 사용하여 추정하고, 양성자 가속기를 통한 실험에서 얻어진 단면적 곡선들을 SEE 발생률 예측에 사용하였다. 약 685 km의 저궤도에 대해 고 경사각과 저 경사각이 고려되었다. 계산 결과는 후보 소자에 대한 SEE 발생률이 저 경사각에서는 수용할만한 것이었지만 고 경사각의 경우에는 최악의 조건에서 문제될 수 있음을 보여준다.

사이클로트론 가속기를 이용한 양성자 우주환경의 모사시험이 수행되었다. 모사시험에 사용된 사이클로트론은 양성자를 약 106-108 protons/cm2/s의 선속에서 200 MeV까지 가속할 수 있다. 가속된 양성자는 우주에서 사용될 MPC860 소자에 입사되었으며, 양성자 조사에 의한 소자의 누적 반응과 순간 반응이 모두 관찰되었다. 주된 순간 반응은 저장된 데이터의 변화였으나, 간헐적인 기능 정지 현상도 관찰되었다. 누적 반응은 소자 내에서 소모되는 전류의 증가로 나타났다.

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 t

A computational method for calculating the geometric factors of an instrument detecting charged particles in the energy range of about 5e500 keV is presented. The method takes into account the presence of electric or magnetic fields that are intentionally generated to clearly separate electrons from positive ions. The method first solves the distribution of electric or magnetic fields near the detectors, and then calculates the trajectory of scattered and unscattered charged particles under the

Triplet Ionospheric Observatory (TRIO) CubeSatforIon, Neutral, Electron MAgneticfields (CINEMA) is a CubeSat with the weight 3 kg that will be operated in the orbit conditions of about 800 km altitude and 90° inclination angle, using the S-band and ultra-high frequency (UHF)-band communication frequencies. Regarding the communication antenna loaded on the satellite, the two patch antennas has the downlink function in the S-band, whereas the two whip antennas has the function to receive the comma

통신해양기상위성의 통신 탑재체가 겪게 될 우주 방사선 환경을 포획된 입자, 태양 양성자 그리고 우주선으로 구분하여 각각 NASA AP8/AE8 모델, JPL91 모델, 그리고 NRL CREME 모델을 사용하여 전산 모사 하였다. 이러한 우주 방사선 환경이 위성 내 통신 탑재체에 미치는 영향을 추정하기 위해 총 이온화 방사선 효과의 분석에 필요한 Dose-Depth 곡선 및 단일사건효과 발생률 계산에 필요한 LET 스펙트럼 구하였다. 통신 탑재체 내의 각 장치별 차폐 효과 차이를 고려한 총 이온화 방사선 효과의 예측을 위해서 기계 구조 모델을 만든 후 구형 분할 방법을 적용하였다. 이를 통해 통신 탑재체 내 각 장치의 위치별 총 이온화 방사선 효과를 예상하였으며 동일한 외부 방사선 환경에 대해서 차폐 효과에 따라 최고 8배까지 방사선 효과가 다르게 나타났다.

We have developed a 2.5-dimensional electromagnetic particle simulation code using the particle-in-cell (PIC) methodto investigate electromagnetic phenomena that occur in space plasmas. Our code is based on the leap-frog method andthe centered difference method for integration and differentiation of the governing equations. We adopted the relativisticBuneman-Boris method to solve the Lorentz force equation and the Esirkepov method to calculate the current densitywhile maintaining charge conserva