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우리별 위성 포획 임무 수행을 위한 소형위성의 궤도 천이 방법 및 분석
이준찬,강경인,Junchan Lee,Kyungin Kang 한국우주과학회 2023 우주기술과 응용 Vol.3 No.2
Active debris removal, a technology that approaches and removes space debris in orbit, and the on-orbit service, a technology for extending the mission life of satellites by fuel charging or by exchanging the battery, are gaining interest with the growth of the space community. SaTReC plans to develop a satellite capable of capturing and removing Korean satellites orbiting in space after the end of their missions. In contrast to the previously launched satellites by Korea, which were mainly intended to observe Earth and the space environment, rendezvous/docking technologies, as required in the future during, for instance, space exploration missions, will be implemented and demonstrated. In this paper, an orbital transition method for next-generation small satellites that will capture and remove space debris will be introduced. It is assumed that a small satellite with a mass of approximately 200 kg will be injected into the mission orbit through Korea Space Launch Vehicle-II in 2027. Because the satellite must access the target using a minimum amount of fuel, an approaching technology using Earth's J2 perturbation force has been developed. This method is expected to enable space debris removal missions for relatively lightweight satellites and to serve as the basis for carrying out a new type of space exploration in what is termed the 'Newspace' era.
Far ultraviolet observations of diffuse, monoenergetic, and broadband auroras
이준찬,민경욱,이지나,Lee, Jun-Chan,Min, Kyoung-Wook,Lee, Chi-Na 한국천문학회 2012 天文學會報 Vol.37 No.2
Discrete auroras, with unique shapes embedded in diffuse auroras, are generally associated with precipitating electrons that originate from the plasma sheet and are accelerated on the way as they travel to polar regions along the field lines. Two acceleration mechanisms have been proposed: quasi-static electric fields and dispersive Alfven waves, which are believed to yield monoenergetic peaks and broadband features in the particle spectra, respectively. Hence, it should be interesting to see how the two different mechanisms, through their characteristic spectra of the accelerated electrons, produce distinct auroral images and spectra, especially in the far ultraviolet (FUV) wavelengths as the long and short Lyman-Birge-Hopfield (LBH) bands exist as well as the strong absorption band of molecular oxygen in the FUV band. In fact, we have previously shown, using the simultaneous observations of precipitating electrons and the corresponding FUV spectra, that the discrete auroras associated with inverted-V events have a stronger relative intensity of the long LBH to the short LBH compared to diffuse auroras, especially when the peak energy is above a few keV. In this paper, we would like to focus on the differences in the FUV images and spectra between the two discrete auroras of the monoenergetic and broadband cases, again based on the study using the dataset of simultaneous observations of particles and FUV spectral images.
Space Plasma Detectors on NEXTSat-1 for Ionospheric Measurements
이준찬,민경욱,유광선,강경인,신구환,손종대,나고운 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.72 No.11
This paper describes the Space Plasma Detectors (SPD) on board the Next Generation Small Satellite-1 (NEXTsat-1), which will observe the thermal plasmas of the ionosphere, especially the plasma irregularities in the low and the middle latitude regions. A SPD consists of a disk-type Langmuir Probe (LP), a Retarding Potential Analyzer (RPA), and an Ion Drift Meter (IDM), which will measure the electron densities and temperatures, the ion densities and temperatures as well as the ion components, and the ion drift velocities, respectively. Whereas SPD employ conventional designs, a high cadence of nominal 100 msec will enable us to study small-scale structures of irregularities, such as plasma bubbles and blobs, with a spatial resolution of less than a kilometer at an altitude of ~ 575 km. Furthermore, the high-resolution mode of the LP operating at a 20 msec cadence will provide data on the electron density and temperature variations with an even better spatial resolution. The NEXTSat-1 is scheduled for launch in early 2018.
류광선,이준찬,김손구,신구환,차원호,민경욱,Vitaly P. Kim,장태진 한국우주과학회 2017 Journal of Astronomy and Space Sciences Vol.34 No.4
A space plasma facility has been operated with a back-diffusion-type plasma source installed in a mid-sized vacuum chamber with a diameter of ~1.5 m located in Satellite Technology Research Center (SaTReC), Korea Advanced Institute of Science and Technology (KAIST). To generate plasma with a temperature and density similar to the ionospheric plasma, nickel wires coated with carbonate solution were used as filaments that emit thermal electrons, and the accelerated thermal electrons emitted from the heated wires collide with the neutral gas to form plasma inside the chamber. By using a disk-type Langmuir probe installed inside the vacuum chamber, the generation of plasma similar to the space environment was validated. The characteristics of the plasma according to the grid and plate anode voltages were investigated. The grid voltage of the plasma source is realized as a suitable parameter for manipulating the electron density, while the plate voltage is suitable for adjusting the electron temperature. A simple physical model based on the collision cross-section of electron impact on nitrogen molecule was established to explain the plasma generation mechanism.