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        검색결과 13

        1.
        2020.06 구독 인증기관 무료, 개인회원 유료
        The University will contribute, through its high quality of education, training and research, to the containment, reduction and management of the problems confronting humanity in the transition to sustainable way of life utilizing the latest technologies of distance learning. Through international collaboration and leadership, it will generate, mobilize and share knowledge, experience and skills throughout the world so as to promote equitable and sustainable progress and to preserve and enhance the natural world on which humanity depends. As merit of the location of center in Northeastern Asia and North and South countries, Jeju Island has a remarkable natural beauty matching with unique environmental culture tradition, and a wide range of expertise, connections and capabilities in regard to global commerce, finance and transportation, and to the management of watersheds and biodiversity as a newly established international free city, all of which are relevant to world environment of sustainable development.
        4,000원
        4.
        2021.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this study, a preliminary trajectory design is conducted for a conceptual spacecraft mission to a near-Earth asteroid (NEA) (99942) Apophis, which is expected to pass by Earth merely 32,000 km from the Earth’s surface in 2029. This close approach event will provide us with a unique opportunity to study changes induced in asteroids during close approaches to massive bodies, as well as the general properties of NEAs. The conceptual mission is set to arrive at and rendezvous with Apophis in 2028 for an advanced study of the asteroid, and some near-optimal (in terms of fuel consumption) trajectories under this mission architecture are to be investigated using a global optimization algorithm called monotonic basin hopping. It is shown that trajectories with a single swing-by from Venus or Earth, or even simpler ones without gravity assist, are the most feasible. In addition, launch opportunities in 2029 yield another possible strategy of leaving Earth around the 2029 close approach event and simply following the asteroid thereafter, which may be an alternative fuel-efficient option that can be adopted if advanced studies of Apophis are not required.
        5.
        2020.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This study designs and analyzes satellite formation flying concepts for the Small scale magNetospheric and Ionospheric Plasma Experiments (SNIPE) mission, that will observe the near-Earth space environment using four nanosats. To meet the requirements to achieve the scientific objectives of the SNIPE mission, three formation flying concepts are analyzed: a crossshape formation, a square-shape formation, and a cross-track formation. Of the three formation flying scenarios, the crosstrack formation scenario is selected as the final scenario for the SNIPE mission. The result of this study suggests a relative orbit control scenario for formation maintenance and reconfiguration, and the initial relative orbits of the four nanosats meeting the formation requirements and thrust limitations of the SNIPE mission. The formation flying scenario is validated by calculating the accumulated total thrust required for the four nanosats. If the cross-track formation scenario presented in this study is applied to the SNIPE mission, it is expected that the mission will be successfully accomplished.
        6.
        2018.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        A previous exo-terrestrial life-detecting experiment, which was conducted on Mars, sought to detect the products of glucose metabolism, the most common biological process on Earth (Viking biological experiment). Today, glucose metabolism is not considered the universal process of life survival. As NASA plans to launch an orbiter mission in the near future (2020s, the Clipper) and ultimately conduct a lander mission on Europa, a detection experiment that can give broader information regarding habitability is highly required. In this study, we designed a life-detecting experiment using a more universal feature of life, the amphipathic molecular membrane, theoretically considering the environment of Europa (waterdominant environment). This designed experiment focuses on finding and profiling hydrophobic cellular membrane-like microstructures. Expected results are given by conceptual data analysis with plausible hypothetical samples.
        7.
        2017.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The current study designs the mission orbit of the lunar CubeSat spacecraft to measure the lunar local magnetic anomaly. To perform this mission, the CubeSat will impact the lunar surface over the Reiner Gamma swirl on the Moon. Orbit analyses are conducted comprising ΔV and error propagation analysis for the CubeSat mission orbit. First, three possible orbit scenarios are presented in terms of the CubeSat’s impacting trajectories. For each scenario, it is important to achieve mission objectives with a minimum ΔV since the CubeSat is limited in size and cost. Therefore, the ΔV needed for the CubeSat to maneuver from the initial orbit toward the impacting trajectory is analyzed for each orbit scenario. In addition, error propagation analysis is performed for each scenario to evaluate how initial errors, such as position error, velocity error, and maneuver error, that occur when the CubeSat is separated from the lunar orbiter, eventually affect the final impact position. As a result, the current study adopts a CubeSat release from the circular orbit at 100 km altitude and an impact slope of 15°, among the possible impacting scenarios. For this scenario, the required ΔV is calculated as the result of the ΔV analysis. It can be used to practically make an estimate of this specific mission’s fuel budget. In addition, the current study suggests error constraints for ΔV for the mission.
        8.
        2014.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The communications link in a space program is a crucial point for upgrading its performance by handling data between spacecraft bus and payloads, because spacecraft’s missions are related to the data handling mechanism using communications ports such as a controlled area network bus (CAN Bus) and a universal asynchronous receiver and transmitter (UART). The NEXTSat-1 has a lot of communications ports for performing science and technology missions. However, the top level system requirements for the NEXTSat-1 are mass and volume limitations. Normally, the communications for units shall be conducted by using point to point link which require more mass and volume to interconnect. Thus, our approach for the novel communications link in the NEXTSat-1 program is to use CAN and serializer and deserializer low voltage differential signal (SerDesLVDS) to meet the system requirements of mass and volume. The CAN Bus and SerDesLVDS were confirmed by using already defined communications link for our missions in the NEXTSat-1 program and the analysis results were reported in this study in view of data flow and size analysis.