• Journal of Astronomy and Space Sciences
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• 제33권3호
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• pp.211-219
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• 2016

Korea's lunar exploration project includes the launching of an orbiter, a lander (including a rover), and an experimental orbiter (referred to as a lunar pathfinder). Laser altimeters have played an important scientific role in lunar, planetary, and asteroid exploration missions since their first use in 1971 onboard the Apollo 15 mission to the Moon. In this study, a laser altimeter was proposed as a scientific instrument for the Korean lunar orbiter, which will be launched by 2020, to study the global topography of the surface of the Moon and its gravitational field and to support other payloads such as a terrain mapping camera or spectral imager. This study presents the baseline design and performance model for the proposed laser altimeter. Additionally, the study discusses the expected performance based on numerical simulation results. The simulation results indicate that the design of system parameters satisfies performance requirements with respect to detection probability and range error even under unfavorable conditions.

• 천문학회보
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• 제44권2호
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• pp.45.3-45.3
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• 2019

Since the high throughput for diffuse objects and the wide-area survey even with a small telescope can be achieved in space, infrared (IR) obervations have been tried through small missions in Korea. Based upon the previous technical development for infrared spectro-photometric instrument, NISS (Near-infrared Imaging Spectrometer for Star formation history) onboard NEXTSat-1, we participated in the all-sky infrared spectro-photometric survey mission, SPHEREx. The SPEHREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer) was selected as the NASA MIDEX (Medium-class Explorer) mission (PI Institute: Caltech) in this February. As an international partner, KASI will take part in the hardware development, the operation and the science for the SPHEREx. The SPHEREx will perform the first all-sky infrared spectro-photometric survey to probe the origin of our Universe, to explore the origin and evolution of galaxies, and to explore whether planets around other stars could harbor life. For the purpose of the all-sky survey, the SPHEREx is designed to have a wide FoV of 3.5 × 11.3 deg. as well as wide spectral range from 0.75 to 5.0㎛. Here, we report the status of the SPHEREx project and the progress in the Korean participation.

• 터널과지하공간
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• 제33권5호
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• pp.373-387
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• 2023

우주 여행이 시작된 이래로 우주 행성에 대한 과학적 탐사는 인간의 상상력을 높이고 있다. 화성에 대한 임무는 지구에서 생명체가 언제, 어디서, 어떻게 시작되었는지에 대한 중요한 질문에 답을 제공할 수 있으며, 이 임무는 현지 우주 자원 활용(ISRU) 개념을 통해서만 실행 가능하다. 이 논문에서는 현재 우주 강국들을 중심으로 진행 중인 화성 탐사를 다루며, 인공 화성토양 조사와 탐사 로버의 이동성 연구를 중점으로 다루고 있다. 화성의 실제 지상 환경을 모사하기 위해서는 수십 톤의 토양이 필요하므로 원료 확보와 처리 과정도 고려되어야 한다. 이를 위해 화성 표면 토양과 유사한 특성을 가진 인공 토양을 선별하고, 인공 화성토양 개발을 위한 필요 사항을 제시한다. 이 연구를 통해 화성 탐사 임무에서 로버의 이동성을 평가하는 데 필요한 적절한 화성 토양을 개발하는 데 도움이 될 것으로 기대된다.

• 우주기술과 응용
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• 제4권2호
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• pp.137-152
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• 2024

현재 마이크로중력 환경을 활용한 과학실험은 초 단위 정도의 짧은 시간 동안 실험이 수행 가능한 낙하 탑부터 시간제한이 없는 우주정거장 등 여러 분야에서 수행되고 있다. 하지만 과학 실험에 필요한 긴 시간이 확보된 마이크로중력 환경을 구현하기 위해서는 적지 않은 개발비용과 시간이 소모된다. 따라서 고비용이 수반되는 마이크로중력 환경 실험을 큐브위성에서 수행한다면 저비용 고효율의 이점으로 과학 실험의 다양성과 시간의 제약에서 자유도가 더욱 높아질 것으로 판단된다. 이러한 특장점을 살린 KMSL(Korea Microgravity Science Laboratory) 큐브위성은 마이크로중력 환경에서의 과학 임무를 수행하였던 위성이다. KMSL 위성은 2021년 3월 22일 카자흐스탄 바이코누르 발사기지에서 Soyuz2.1a 발사체에 의해 발사되었고, 약 2개월간 정상적으로 임무를 수행하였다. 본 논문에서는 KMSL 위성의 운영 경험과 발생한 문제에 대한 분석을 바탕으로 마이크로중력 환경에서의 과학 임무를 성공적으로 수행하기 위한 해결책과 교훈을 제시하고자 한다.

• 한국항공우주학회지
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• 제38권9호
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• pp.925-932
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• 2010

스페이스와이어는 우주비행체 구성 요소들 간의 고속 정보 전달을 위하여 링크 또는 네트워크 형태로 연결시켜주는 표준으로서 기존의 방식보다 저렴한 비용에 뛰어난 성능을 발휘하도록 고안되었다. 스페이스와이어는 ESA, NASA 그리고 JAXA의 다수의 우주개발 프로그램에 적용되었고 향후 국내의 인공위성 개발 프로그램에 적용될 것이다. 스페이스와이어 기술을 효과적으로 유연하게 적용하기 위해서는 관련 기술의 확보가 필수적이다. 본 논문은 과학기술위성 3호의 대용량 메모리 유닛에 적용되는 스페이스와이어 링크 인터페이스의 개발 결과에 관해 소개한다.

• Journal of Astronomy and Space Sciences
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• 제21권4호
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• pp.329-342
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• 2004

In this paper, we present preliminary feasibility studies on three types of solar observation payloads for future Korean Science and Technology Satellite (STSAT) programs. The three candidates are (1) an UV imaging telescope, (2) an UV spectrograph, and (3) an X-ray spectrometer. In the case of UV imaging telescope, the most important constraint seems to be the control stability of a satellite in order to obtain a reasonably good spatial resolution. Considering that the current pointing stability estimated from the data of the Far ultraviolet Imaging Spectrograph (FIMS) onboard the Korean STSAT-1, is around 1 arc minutes/sec, we think that it is hard to obtain a spatial resolution sufficient for scientific research by such an UV Imaging Telescope. For solar imaging missions, we realize that an image stabilization system, which is composed of a small guide telescope with limb sensor and a servo controller of secondary mirror, is quite essential for a very good pointing stability of about 0.1 arcsec. An UV spectrograph covering the solar full disk seems to be a good choice in that there is no risk due to poor pointing stability as well as that it can provide us with valuable UV spectral irradiance data valuable for studying their effects on the Earth's atmosphere and satellites. The heritage of the FIMS can be a great advantage of developing the UV spectrograph. Its main disadvantage is that two major missions are in operation or scheduled. Our preliminary investigations show that an X-ray spectrometer for the full disk Sun seems to be the best choice among the three candidates. The reasons are : (1) high temporal and spectral X-ray data are very essential for studying the acceleration process of energetic particles associated with solar flares, (2) we have a good heritage of X-ray detectors including a rocket-borne X-ray detector, (3) in the case of developing countries such as India and Czech, solar X-ray spectrometers were selected as their early stage satellite missions due to their poor pointing stabilities, and (4) there is no planned major mission after currently operating Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) mission. Finally, we present a preliminary design of a solar X-ray spectrometer covering soft X-ray (2 keV) to gamma ray (10 MeV).

• 천문학회보
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• 제44권1호
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• pp.62.2-62.2
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• 2019

The ADF-S (AKARI Deep Field - South) toward South Ecliptic Pole is one of the deep survey fields designed for the study of Extragalactic Background Light (EBL). The deep extragalactic survey was initiated by AKARI far-infrared deep observations. Other space missions (e.g., Euclid, NISS, SPHEREx) will perform the deep observations in the ADF-S. Based upon the recent optical survey with KMTNet, we can identify the optical counterparts for dusty star-forming galaxies such as ULIRG, DOG, SMG. Among them, the Dust-Obscured Galaxies (hereafter DOGs with f(24um)/f(R) > 1,000) in the heavily obscured system are expected to play an important role in the formation of most massive galaxies. We have newly discovered ~100 DOGs in ~12 sq. deg. of the ADF-S from our optical survey with KMTNet. We also confirmed that some of DOGs host the most luminous AGN for their black hole masses through the near-infrared spectroscopic follow-ups. Here, we report the properties of high-z hyperluminous DOGs in the ADF-S.

• Journal of Astronomy and Space Sciences
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• 제41권2호
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• pp.79-85
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• 2024

Nowadays, the trend in lunar exploration missions is shifting from prospecting lunar surface to utilizing in-situ resources and establishing sustainable bridgehead. In the past, experiments were mainly focused on rover maneuvers and equipment operations. But the current shift in trend requires more complex experiments that includes preparations for resource extraction, space construction and even space agriculture. To achieve that, the experiment requires a sophisticated simulation of the lunar environment, but we are not yet prepared for this. Particularly, in the case of lunar regolith simulants, precise physical and chemical composition with a rapid development speed rate that allows different terrains to be simulated is required. However, existing lunar regolith simulants, designed for 20th-century exploration paradigms, are not sufficient to meet the requirements of modern space exploration. In order to prepare for the latest trends in space exploration, it is necessary to innovate the methodology for producing simulants. In this study, the basic framework for lunar regolith simulant development was established to realize this goal. The framework not only has a sample database and a database of potential simulation target compositions, but also has a built-in function to automatically calculate the optimal material mixing ratio through the particle swarm optimization algorithm to reproduce the target simulation, enabling fast and accurate simulant development. Using this framework, we anticipate a more agile response to the evolving needs toward simulants for space exploration.

• International Journal of Aeronautical and Space Sciences
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• 제14권1호
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• pp.11-18
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• 2013

Human spaceflight experience in extra-vehicular activity (EVA) is limited to two regimes: the micro-gravity environment of Earth orbit, and the lunar surface environment at one-sixth of Earth's gravity. Future human missions to low-gravity bodies, including asteroids, comets, and the moons of Mars, will require EVA techniques that are beyond the current experience base. In order to develop robust approaches for exploring these small bodies, the dynamics associated with human exploration on low-gravity surface must be characterized. This paper examines the translational and rotational motion of an astronaut on the surface of a small body, and it is shown that the low-gravity environment will pose challenges to the surface mobility of an astronaut, unless new tools and EVA techniques are developed. Possibilities for addressing these challenges are explored, and utilization of the International Space Station to test operational concepts and hardware in preparation for a low-gravity surface EVA is discussed.

• 한국항공우주학회지
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• 제35권8호
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• pp.735-740
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• 2007

별센서는 우주 공간상의 별 이미지를 사용하여 초정밀 자세 정보를 제공한다. 그러나 센서가 태양광이나 지구 반사광(Albedo)으로부터의 회피각이 보장되지 않는 경우 센서 출력의 정밀도를 보장할 수 없거나 출력을 얻을 수 없다. 이 논문은 별센서의 탑재 방향에 따른 태양 및 지구 회피각의 특성에 대한 연구 결과를 제시하고 있다. 아울러 지구 관측 임무에 적합한 별센서의 탑재 방향 결정을 위한 체계적인 방법을 제시한다.