• Journal of Astronomy and Space Sciences
• /
• 제26권4호
• /
• pp.567-588
• /
• 2009

한일공동VLBI상관기(Korea-Japan Joint VLBI Correlator, KJJVC)는 2010년 정상가동을 목표로 한국과 일본 간 공동으로 개발이 진행되고 있다. 이 연구에서는 KJJVC의 핵심이 되는 VLBI 상관 서브시스템(VLBI Correlation Subsystem, VCS)과 동일한 규격을 갖는 소프트웨어 상관기를 개발하였다. 소프트웨어 상관기는 VCS와 같은 8Gbps급, 8192출력채널, 262,144점 FFT(Fast Fourier Transform)의 규격을 갖고 있으며, VCS의 하드웨어 규격과 동일한 함수 알고리즘과 연산 레지스터를 적용하고 있다. 개발한 소프트웨어 상관기의 성능을 확인하기 위해 일본국립천문대의 VERA(VLBI Exploration of Radio Astrometry) 관측망으로 관측한 스펙트럼선과 연속파 천체를 대상으로 상관처리 실험을 수행하고, 그 결과는 미타카 FX 상관기의 스펙트럼 모양, 위상변화, 프린지 검출 등을 비교하였다. 실험을 통하여, VERA 관측데이터를 이용한 소프트웨어 상관기의 결과는 미타카 FX 상관기의 상관결과와 일치하는 것을 확인하여 그 유효성을 입증하였다. 향후 개발한 소프트웨어 상관기는 GUI와 같은 사용자 인터페이스와 상관 후 처리 부분을 개선하면 KJJVC와 함께 한국우주전파관측망(Korean VLBI Network, KVN)의 소프트웨어 상관기로 활용할 수 있을 것으로 기대된다.

• 천문학회보
• /
• 제46권2호
• /
• pp.59.1-59.1
• /
• 2021

The Korean spacecraft for the exploration of Apophis will be equipped with an optical navigation camera with a wide-angle lens. The major purpose of the wide-angle camera is to capture imagery during the rendezvous phase in order to determine the spacecraft's position and the pointing direction relative to the asteroid Apophis. Two potential sciences, however, can be achieved by the wide-angle camera: (1) to measure the high-order gravity terms, and (2) to capture possible ejecting small particles. In this presentation, we will discuss instrument specification and operation scenario required to accomplish the given science objectives.

• 지구물리와물리탐사
• /
• 제16권4호
• /
• pp.284-292
• /
• 2013

삼각망에서 얻은 2차원 변위자료로부터 주축변형, 회전, 팽창등을 산출하는 안정된 계산순서를 제시하였으며, 이들 추산치의 오차가 삼각망의 면적간에 반비례하므로 자료망의 크기를 택함에 유의하여야함을 지적하였다. 이 순서를, 2011년 토호쿠지진에 의해 발생한 한반도지역의 변위의 GPS관측자료에 적용하여 안정된 추산치들을 얻었다.

• 항공우주정책ㆍ법학회지
• /
• 제spc호
• /
• pp.247-270
• /
• 2007

Space development and utilization must be conducted within a framework of "peaceful uses" principle under Space Treaty. Japan ratified the treaty in 1967, and interpreted "peaceful uses" as "non-military uses" then. A ghost of "peaceful uses" principle has been hung over Japan up to the moment. Japan's space development and utilization has been conducted with genuine academic interest, and therefore Japan did not introduce space infrastructures to national security policy and did not facilitate growth of space industry. When the Cold War ended, Northeast Asian security environment makes Japan difficult to maintain an interpretation as "non-military uses". Besides the change of external security environment, the domestic industry situation and a series of rocket launching failure needed reexamination of Japan's space policy. Japan is gradually changing its space policy, and introducing space infrastructure in a national security policy under a "generalization" theory that gave a broad interpretation of "peaceful uses" principle. Council for Science and Technology Policy (CSTP) adopted a basic strategy of Japan's space policy in 2004. Since then, a long-term report of Japan Aerospace Exploration Agency (JAXA), an investigation report of Society of Japanese Aerospace Companies (SJAC) and a proposal of Japan Business Federation (JSF) were followed. Japan will promote space development and utilization in national security policy with a "strictly defensive defense" strategy and "non-aggressive uses"principle for protection of life and property of Japanese people and stabilization of East Asian countries.

• Journal of Astronomy and Space Sciences
• /
• 제31권3호
• /
• pp.247-264
• /
• 2014

In this paper, a brief but essential development strategy for the lunar orbit determination system is discussed to prepare for the future Korea's lunar missions. Prior to the discussion of this preliminary development strategy, technical models of foreign agencies for the lunar orbit determination system, tracking networks to measure the orbit, and collaborative efforts to verify system performance are reviewed in detail with a short summary of their lunar mission history. Covered foreign agencies are European Space Agency, Japan Aerospace Exploration Agency, Indian Space Research Organization and China National Space Administration. Based on the lessons from their experiences, the preliminary development strategy for Korea's future lunar orbit determination system is discussed with regard to the core technical issues of dynamic modeling, numerical integration, measurement modeling, estimation method, measurement system as well as appropriate data formatting for the interoperability among foreign agencies. Although only the preliminary development strategy has been discussed through this work, the proposed strategy will aid the Korean astronautical society while on the development phase of the future Korea's own lunar orbit determination system. Also, it is expected that further detailed system requirements or technical development strategies could be designed or established based on the current discussions.

• 한국항공우주학회지
• /
• 제40권1호
• /
• pp.69-77
• /
• 2012

1990년대 들어 달 탐사가 재개 된 후 2000년대부터 세계우주선진국들을 중심으로 달을 선점하기 위한 치열한 달 탐사 경쟁이 벌어지고 있다. 우리나라도 2020년경 자력 달 탐사를 목표로 선행연구를 수행 중에 있다. 본 연구에서는 한국형 달 탐사를 대비하여 지구에서 달로 가는 천이궤적 중 연료 최소화를 위해 다양한 천이궤적의 Delt-V를 비교 분석하였다. 시뮬레이션을 통해 한국형 달 탐사에 가장 적합한 지구-달 천이궤적을 확인하였으며, 실제 한국형 달 탐사시 유용한 자료로 사용될 것이다.

• 암석학회지
• /
• 제19권4호
• /
• pp.245-254
• /
• 2010

오늘날 X-선을 이용한 표면탐사기술은 널리 활용되는 기술의 하나이다. 또한 X-선 측정기술은 행성표면탐사를 위한 연구에서도 궤도선 및 주행장치 탑재용 과학장비로서도 성공적으로 활용된 예가 여러 차례 있었다. 우리나라는 2020년경 궤도선 및 착륙선을 이용한 달 탐사계획을 추진하고 있으며, 이에 맞추어 궤도 및 착륙선 탑재용 우선 순위 과학장비의 개발 및 달에 관한 기초연구를 해야 하는 실정이다. 따라서 X-선 측정기술을 이용한 행성탐사의 현황 및 이 분야의 기술 발전 전망에 대한 고찰을 하였다.

• Journal of Astronomy and Space Sciences
• /
• 제32권3호
• /
• pp.247-256
• /
• 2015

In this work, an efficient method with which to evaluate the high-degree-and-order gravitational harmonics of the non-sphericity of a central body is described and applied to state predictions of a lunar orbiter. Unlike the work of Song et al. (2010), which used a conventional computation method to process gravitational harmonic coefficients, the current work adapted a well-known recursion formula that directly uses fully normalized associated Legendre functions to compute the acceleration due to the non-sphericity of the moon. With the formulated algorithms, the states of a lunar orbiting satellite are predicted and its performance is validated in comparisons with solutions obtained from STK/Astrogator. The predicted differences in the orbital states between STK/Astrogator and the current work all remain at a position of less than 1 m with velocity accuracy levels of less than 1 mm/s, even with different orbital inclinations. The effectiveness of the current algorithm, in terms of both the computation time and the degree of accuracy degradation, is also shown in comparisons with results obtained from earlier work. It is expected that the proposed algorithm can be used as a foundation for the development of an operational flight dynamics subsystem for future lunar exploration missions by Korea. It can also be used to analyze missions which require very close operations to the moon.

• 한국게임학회 논문지
• /
• 제13권5호
• /
• pp.63-72
• /
• 2013

기존의 학습자에게 제공되는 교육용 콘텐츠의 대부분이 2D 기반의 단방향 교육으로 효과가 현저히 낮은 것으로 나타났다. 이를 개선하기 위하여 본 논문에서는 상호 인터랙션을 적용한 3D 우주탐험을 개발함으로써 학습 몰입도를 높이고 교육효과를 극대화하였다. 제안한 방법은 과학 학습 특성상 기존 2D 개발 기술로는 개념화 및 실체적 접근이 어려운 학습영역을 3D 객체로 제작하였고 이를 학습자가 직접 접근할 수 있도록 동작인식 센서를 이용한 체감형 인터페이스 기술을 연구하여 콘텐츠에 적용하였다. 본 논문의 결과로 학습자는 '3D 우주탐험' 교육용 콘텐츠를 직접 체험함으로써 학생들이 실제 현장에서 수업을 받는 것과 같은 몰입교육에 큰 효과가 있을 것으로 예상된다.

• 천문학회보
• /
• 제46권2호
• /
• pp.57.4-58
• /
• 2021

Asteroids have undergone various processes such as impacts, space weathering, and thermal evolution. Because they expose their surfaces to space without atmosphere, these evolutional processes have been recorded directly on their surfaces. The remote-sensing observations have been conducted to reveal these evolutional histories of the target asteroids. For example, crater and boulder distributions are unambiguous evidence for past nondestructive impacts with other celestial bodies. Multiband and spectroscopic observations have revealed space-weathering history (as well as compositions). Whereas most physical quantities have been examined intensively using spacecraft and telescopes, only a little has been studied on "the grain size". It is one of the fundamental physical quantities for diagnosing the collisional and thermal history of asteroids. Our group has conducted polarimetric research of asteroids (as well as Moon [1]) to determine the particle size and further investigate the evolutional histories of target asteroids [2],[3]. For example, the existence of regolith on an S-type asteroid, Toutatis, was suggested almost twenty years before space exploration [4]. Moreover, we reported that near-Sun asteroids indicate a signature of submillimeter grains, which could be created by a thermal sintering process by solar radiation [5]. However, it is important to note that in-situ polarimetry has not been reported on the asteroid surface, although the Korean Lunar Exploration Program aims to do polarimetry on the lunar surface [6]. Therefore, it is expected that the polarizer mounted on the Korean Apophis spacecraft can make the first estimate of the grain size and its regional variation over the Apophis surface. In this presentation, we outline research of S-type asteroid surfaces through remote-sensing observations and consider the role of polarimetry. Based on this review, we consider the purpose, potentiality, and strategy of the polarimetry using the onboard device for the Apophis spacecraft. We will report a possible polarization phase curve of Apophis estimated from ordinary chondrites and past observational data of S-type asteroids, taking account of the space weathering effect. Based on this estimation, we will consider the strategy of how to determine the particle size (and space weathering degree) of the Apophis surface. We will also mention the detectability of dust hovering on the surface.