• 제목/요약/키워드: 달 임무

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Optimization-Based Determination of Apollo Guidance Law Parameters for Korean Lunar Lander (달착륙 임무를 위한 최적화 기반 아폴로 유도 법칙 파라미터 선정)

  • Jo, Byeong-Un;Ahn, Jaemyung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.8
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    • pp.662-670
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    • 2017
  • This paper proposes an optimization-based procedure to determine the parameters of the Apollo guidance law for Korean lunar lander mission. A lunar landing mission is formulated as a trajectory optimization problem to minimize the fuel consumption and the reference trajectory for the lander is obtained by solving the problem in the pre-flight phase. Some parameters of the Apollo guidance, which are coefficients of the polynomial used to define the guidance command, are selected based on the reference trajectory obtained in the pre-flight phase. A case study for the landing guidance of Korean lunar lander mission using the proposed procedure is conducted to demonstrate its effectiveness.

Requirement Analysis of Navigation System for Lunar Lander According to Mission Conditions (임무조건에 따른 달 착륙선 항법시스템 요구성능 분석)

  • Park, Young Bum;Park, Chan Gook;Kwon, Jae Wook;Rew, Dong Young
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.9
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    • pp.734-745
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    • 2017
  • The navigation system of lunar lander are composed of various navigation sensors which have a complementary characteristics such as inertial measurement unit, star tracker, altimeter, velocimeter, and camera for terrain relative navigation to achieve the precision and autonomous navigation capability. The required performance of sensors has to be determined according to the landing scenario and mission requirement. In this paper, the specifications of navigation sensors are investigated through covariance analysis. The reference error model with 77 state vector and measurement model are derived for covariance analysis. The mission requirement is categorized as precision exploration with 90m($3{\sigma}$ ) landing accuracy and area exploration with 6km($3{\sigma}$ ), and the landing scenario is divided into PDI(Powered descent initiation) and DOI(Deorbit initiation) scenario according to the beginning of autonomous navigation. The required specifications of the navigation sensors are derived by analyzing the performance according to the sensor combination and landing scenario.

Mission Design for a Lunar Orbiter Launched by KSLV-II (한국형발사체를 사용한 달궤도선의 임무 설계)

  • Song, Eun-Jung;Park, Chang-Su;Cho, Sang-Bum;Roh, Woong-Rae
    • Aerospace Engineering and Technology
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    • v.8 no.1
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    • pp.108-116
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    • 2009
  • This paper considers the trajectory design problem for a lunar orbiter when launched by KSLV-II. KSLV-II puts its kick motor stage and lunar orbiter into a low earth orbit, and then the kick motor stage performed the translunar injection. To simulate more realistic situations, TLI (Trans-Lunar Injection) and LOI (Lunar Orbit Injection) maneuvers are modeled as finite burns. The feasibility of the lunar mission by KSLV-II are confirmed by the numerical results that show the reasonable required-velocity and propellant usage.

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Study of the Lunar Regolith using Multi-band Polarimetric Observations

  • Kim, Sungsoo S.;Jung, Minsup;Sim, ChaeKyung;Kim, Il-Hoon;Min, Kyoung Wook;Jin, Ho
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.65.2-65.2
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    • 2014
  • 태양 빛이 달 표면에서 반사될 때는 일부가 편광 된다. 이러한 월면 편광은 달 표토층 입자의 크기와 성분을 알려주는 중요한 정보이나, 이전의 달 궤도선에서는 한 번도 탐사되지 않았다. 또한 달 탐사임무에 있어 틈새시장인 월면 특이지역 연구에도 편광이 중요한 기초자료를 제공한다는 사실이 최근 밝혀졌다. 이에 본 연구진은 한국형 달 탐사선을 위한 우리나라 고유의 창의적 과학 임무 중 하나로 <월면 다파장 편광 탐사>를 제안하며, 이러한 탐사에 필요한 기초연구 및 선행연구를 수행하고 있다. 본 발표에서는 우리가 수행한 지상으로부터의 다파장 편광 관측 결과를 보고하고, 최근 시작한 랩실험과 컴퓨터 시뮬레이션 실험에 대해 소개할 것이다.

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Optimal Earth-Moon Trajectory Design using Constant and Variable Low Thrust (등저추력과 가변저추력을 이용한 지구-달 천이궤적 설계)

  • Song, Young-Joo;Park, Sang-Young;Choi, Kyu-Hong;Sim, Eun-Sup
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.9
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    • pp.843-854
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    • 2009
  • For preparing Korean lunar missions, optimal Earth-Moon transfer trajectory is designed using continuous low thrust. Using both constant and variable low thrusting method, "End-to-End" mission analysis is made from beginning of the Earth departure to the final lunar arrival. Spacecraft's equations of motion is expressed using N-body dynamics including the gravitational effects due to the Earth, Moon, Sun and also with Earth's $J_2$ effects. Planets' exact locations are computed accurately with JPL's DE405 ephemeris. As a results, optimal thrust steering angle's characteristics are discovered which showed almost tangential direction burns at the near of central planets. Also, it is confirmed that variable low thrusting method is more efficient than constant thrusting method, and can save about 5% of fuel consumption. Presented algorithm and various results will give numerous insights into the future Korea's Lunar missions using low thrust engines. Also, it is expected to be used as a basis of more detailed mission analyzing tool.

Design of Deep Space Missions Using a Dedicated Small Launch Vehicle (소형위성 전용 발사체를 이용한 심우주 임무 설계)

  • Choi, Su-Jin;Loucks, Mike;West, Stephen;Seo, Daeban;Lee, Keejoo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.12
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    • pp.877-888
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    • 2022
  • Recently, as the CAPSTONE, a precursor mission for Lunar Gateway, was launched on a small launch vehicle for the purpose of demonstrating communications and navigation technology in the NRHO, large attention was brought to this event that enabled high-impact deep space mission using dedicated small launch vehicle and small spacecraft. In this study, we introduced the concept of a dual launch operation and examined the capability of the new concept in the exploration of the Moon, Mars and asteroid. It turned out a single launch is sufficient for the lunar low orbit mission up to around 247 kg, and the dual launch option can transport 215 kg and 183 kg to nearby destinations as such as Mars and astroid Apophis respectively.

Design and Performance Analysis of DSP Prototype for High Data Rate Transmission of Lunar Orbiter (달 탐사선의 데이터 고속 전송을 위한 DSP 프로토타입 설계 및 성능 분석)

  • Jang, Yeon-Soo;Kim, Sang-Goo;Cho, Kyong-Kuk;Yoon, Dong-Weon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.1
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    • pp.63-68
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    • 2011
  • Many countries all over the world have been doing lunar exploration projects. Korea has also been doing basic research on lunar exploration. The development of communication systems for lunar exploration projects is one of the most important aspects of performing a successful lunar mission. In this paper, we design a DSP (Digital Signal Processor) prototype based on the requirement analysis of a communication link for lunar exploration and implement its core module considering the international standards for deep space communications to perform a basic research on baseband processor development. It is verified by comparing the bit error rate of the DSP prototype with that of a computer simulation.

A Study on Optimal Earth-Moon Transfer Orbit Design Using Mixed Impulsive and Continuous Thrust (순간 및 연속 추력을 이용한 지구-달 최적 전이궤도 설계에 관한 연구)

  • No, Tae-Soo;Jeon, Gyeong-Eon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.7
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    • pp.684-692
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    • 2010
  • Based on the planar restricted three body problem formulation, optimized trajectories for the Earth-Moon transfer are obtained. Mixed impulsive and continuous thrust are assumed to be used, respectively, during the Earth departure and Earth-Moon transfer/Moon capture phases. The continuous, dynamic trajectory optimization problem is reformulated in the form of discrete optimization problem by using the method of direct transcription and collocation, and then is solved using the nonlinear programming software. Representative results show that the shape of optimized trajectory near the Earth departure and the Moon capture phases is dependent upon the relative weight between the impulsive and the continuous thrust.

Preliminary Mission Design of Transfer Orbit of a Lunar Lander Launched by a Korean Space Launch Vehicle (국내 발사체를 이용한 달착륙선 발사시 전이 궤도 예비 임무 설계)

  • Song, Eun-Jung;Lee, Sang-il;Choi, iyoung;Sun, Byung-Chan;Roh, Woong-Rae
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.12
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    • pp.867-875
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    • 2022
  • The preliminary mission analysis of a lunar lander, which is mounted on the upper stage of a Korean space launch vehicle, is performed when landing on the moon through a trans-lunar injection maneuver after being injected into the earth's low orbit by th launcher in this paper. Both direct landing and orbital landing methods, which have each advantage and disadvantages, are applied and their transfer orbit characteristics are analyzed according to the launch date when launching in lunar October 2030. We also analyzed the launch dates which satisfying eclipse conditions, solar elevation conditions, and tracking time intervals such as the US lunar lander Surveyor-1. The obtained results show that the most appropriate launch date is the 4th day of lunar October in case of direct landing method, and the 3rd day in case of indirect landing method, since the argument of perigee of the trans-lunar injection orbit and eclipse conditions are favorable in the dates.

Development of public release system of science mission data from KPLO and future space explorations

  • Kim, Joo Hyeon
    • The Bulletin of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.66.1-66.1
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    • 2020
  • 우리나라는 최초의 우주탐사선이자 달탐사선인 KPLO를 2022년 8월에 발사할 예정이다. KPLO에는 6기의 임무탑재체가 실리게 되며, 이중 4개의 탑재체는 국내의 대학과 정부출연연구소에서 개발하여 달 표면과 주변 우주환경에 대한 과학임무를 수행하게 된다. 이들 국내에서 개발된 과학탑재체가 달 궤도에서 획득한 Data, 즉 과학자료는 지상국에서 수신하여 이를 처리하여 과학연구 혹은 교육 목적으로 활용될 것으로 예상된다. 이러한 태양계 탐사 과학임무로 부터 획득된 과학자료는 과학의 공익성과 연구교류 활성화를 위해서 국제적으로 대중에게 공개하고 있다. 이에 KPDS도 일반 사용자들이 인터넷으로 이들 과학자료를 쉽게 검색하고 다운로드 받을 수 있도록 한국항공우주연구원에서는 KARI Planetary Data System(KPDS)를 구축하고 있으며, 일반에게 공개할 예정이다. KPDS는 단순히 과학자료를 제공하는 것에서 그치지 않고, 이들 과학자료가 NASA에서 개발한 PDS4 표준을 준수하고 있는지 검증함으로써 세계 각국의 타 우주관련 기관과 상호활용이 용이하도록 하여 활용성을 높은 과학자료로 관리하게 된다. 또한 이러한 PDS4 표준 준수여부를 검증함으로써 KPLO 이후 우리나라에서 수행하게 될 미래의 우주탐사 과학임무로부터 획득될 과학자료도 저장, 공개를 할 수 있도록 KPDS는 범용성을 고려하여 개발하고 있다.

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