• Title/Summary/Keyword: Lander

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Investigation of Structural Reliability on Solder Joint According to Heater Set-point of the Lunar Lander (달 착륙선의 히터 작동온도 설정에 따른 솔더 접합부의 구조적 신뢰성 분석)

  • Jeon, Young-Hyeon;Park, Tae-Yong;Lee, Jang-Joon;Kim, Jung-Hoon;Oh, Hyun-Ung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.2
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    • pp.167-174
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    • 2018
  • The heater is applied to the lunar lander for securing its survivability under severe lunar thermal environment during 14 days of night time. For this, the heater on/off set-points shall be determined to minimize the power consumption due to the limited power generation of lunar lander during night time. In addition, the temperature changes of the lander according to the heater set-point is also an important factor because it is related to thermo-mechanical reliability on solder joint of on-board electronics. In this study, we investigated thermo-mechanical reliability on solder joint according to the heater set-point by using commercial reliability and a life prediction tool of Sherlock based on the thermal analysis results of lunar lander that is a year of the mission lifetime.

Development of a Structure for Lunar Lander Demonstrator (달착륙선 지상시험모델의 구조체 개발)

  • Son, Taek-Joon;Na, Kyung-Su;Lim, Jae Hyuk;Kim, Kyung-Won;Hwang, Do-Soon
    • Aerospace Engineering and Technology
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    • v.12 no.1
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    • pp.213-220
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    • 2013
  • Korean Lunar Explorer is planned to be launched in the 2020s according to national space development strategy. The Lunar Explorer will be developed as two unmanned light weight models: a lunar orbiter and a lunar lander. The Lunar Explorer's structure should be designed to have light weight due to constraints from launcher as well as to provide structural safety against launch load, in-orbit condition and landing condition and to serve accommodation space for mission equipment. Core technology related to structural development of lunar explorer should be developed in advance. Especially, for lunar lander, technology for developing landing gear which enables lander to land safely on lunar surface is required essentially. This paper deals with structural development of lunar lander ground test model including design, manufacturing and test.

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.

A Study on Development of the Hybrid Shock Absorber for Lunar Lander (달 착륙선 하이브리드 충격 흡수장치의 개발에 관한 연구)

  • Lee, Jaehyeong;Hwang, Jai-hyuk;Bae, Jae-sung;Lim, Jaehyuk
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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    • pp.81-86
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    • 2012
  • The shock absorber is very important in various mechanical field. Without the shock absorber, the structure might be broken. For lunar lander, honeycomb shock absorber to absorber the shock by using plastic deformation of honeycomb has been used. It is cheap and simple to use but impossible using again without changing the honeycomb. The oleo-pneumatic type shock absorber is not able to use in the cosmos because it is vacuum and its temperature. This study suggests the hybrid shock absorber combined spring-ratchet mechanical shock absorber and eddy current electromagnetic damper. The ratchet restricts rebound of lunar lander and the spring converts the impact energy to the potential energy of the spring. The eddy current damper dissipates the impact energy by eddy current force without contact between the parts. This hybrid shock absorber is reusable while the honeycomb shock absorber isn't. The impact absorbing test of the hybrid shock absorber was carried out. This paper shows that the compared results the hybrid shock absorber with ratchet and without ratchet and evaluates the possibility of using for lunar lander.

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Control of powered descent phase for a Lunar lander using PID controller (PID 제어기를 이용한 달착륙선의 powered descent phase 유도제어)

  • Jo, Sung-Jin;Min, Chan-Oh;Lee, Dae-Woo;Cho, Kyeum-Rae
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.5
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    • pp.408-415
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    • 2011
  • The moon landing is composed of the de-orbit descent phase, powered descent phase, and the powered descent phase is divide into 3-sub phase of the braking, approach, final landing phase. In this paper, the lunar lander perform landing control using 3-sub phase of optimal trajectory. First, generate the reference trajectory using gauss pseudo-spectral method. Thereafter generate PID controller using altitude and velocity error in each direction. Finally the lunar lander landing system constitute using the Simulink of Matlab, and perform simulation.

Multibody simulation and descent control of a space lander

  • Pagani, A.;Azzara, R.;Augello, R.;Carrera, E.
    • Advances in aircraft and spacecraft science
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    • v.7 no.2
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    • pp.91-113
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    • 2020
  • This paper analyzes the terminal descent phase of a space lander on a surface of a celestial body. A multibody approach is adopted to build the physical model of the lander and the surface. In this work, a legged landing gear system is considered. Opportune modelling of the landing gear crashbox is implemented in order to accurately predict the kinetic energy. To ensure the stability of the lander while impacting the ground and to reduce the contact forces that arise in this maneuver, the multibody model makes use of a co-simulation with a dedicated control system. Two types of control systems are considered; one with only position variables and the other with position and velocity variables. The results demonstrate the good reliability of modern multibody technology to incorporate control algorithms to carry out stability analysis of ground impact of space landers. Moreover, from a comparison between the two control systems adopted, it is shown how the velocity control leads to lower contact forces and fuel consumption.

Heat Flux Analysis of Lunar Lander for Potential Landing Candidate Area (달 착륙선의 착륙 후보지별 열 유입량 분석)

  • Park, Tae-Yong;Chae, Bong-Geon;Lee, Jang-Joon;Kim, Jung-Hoon;Oh, Hyun-Ung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.4
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    • pp.324-331
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    • 2018
  • The thermal environment on lunar surface is more severe than that of earth's surface or low earth orbit because of the long daytime and nighttime due to 28 days of rotation cycle of moon. Thus, analyzing heat flux on lunar lander at potential landing sites is important to determine the landing site in its initial design phase. In this study, thermal model of lunar regolith that can simulate lunar surface temperature was constructed for analyzing thermal characteristics according to the potential landing sites of lunar lander. The heat flux analyses were performed various latitudes of equator, mid-latitude, polar regions, lunar mare and highland. In addition, we also investigated the heat flux of lunar lander when it is landed on adjacent area to hill.

Analysis of landing mission phases for robotic exploration on phobos mar's moon

  • Stio, A.;Spinolo, P.;Carrera, E.;Augello, R.
    • Advances in aircraft and spacecraft science
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    • v.4 no.5
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    • pp.529-541
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    • 2017
  • Landing phase is one of the crucial and most important phases during robotic aerospace explorations. It concerns the impact of the landing module of a spacecraft on a celestial body. Risks and uncertainties of landing are mainly due to the morphology of the surface, the possible presence of rocks and other obstacles or subsidence. The present work quotes results of a computational analysis direct to investigate the stability during the landing phase of a lander on Phobos, a Mars Moon. The present study makes use of available software tools for the simulation analyses and results processing. Due to the nature of the system under consideration (i.e., large displacements and interaction between several systems), multibody simulations were performed to analyze the lander's behavior after the impact with the celestial body. The landing scenario was chosen as a result of a DOE (Design of Experiments) analysis in terms of lander velocity and position, or ground slope. In order to verify the reliability of the present multibody methodology for this particular aerospace issue, two different software tools were employed in order to emphasize two different ways to simulate the crash-box, a particular component of the system used to cushion the impact. The results show the most important frames of the simulations so as to provide a general idea about how lander behaves in its descent and some trends of the main characteristics of the system. In conclusion, the success of the approach is demonstrated by highlighting that the results (crash-box shortening trend and lander's kinetic energy) are comparable between the two tools and that the stability is ensured.

Analysis of Plume Impingement Effect of Lunar Lander (지상시험 모델용 달착륙선 플룸 해석을 통한 추력기간의 간섭 효과 분석)

  • Choi, Ji-Yong;Lee, Jae-Won;Kim, Su-Kyum;Han, Cho-Young;Yu, Myoung-Jong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.254-257
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    • 2011
  • Two types of thrusters(Descent Control Thruster (DCT) for reducing landing speed and Attitude Control Thruster (ACT) for attitude control) are mounted on the propulsion system of Ground test model lunar lander. In this paper, plume impingement effect and ground effect between DCT Modules are analyzed using numerical method when the impact occurred close to the ground.

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