• Title/Summary/Keyword: satellite launch vehicle

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Prediction of Kick Motor Mass Variation (킥모터 무게 변화 예측)

  • Kil, Gyoung-Sub;Kho, Hyeon-Seok;Kim, Byung-Hun;Cho, In-Hyun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.203-206
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    • 2008
  • Kick motor(KM) for KSLV-I second stage propulsion system is the main hardware that is necessary for launching satellite to it's track. The mass of the kick motor changes with combustion time because the heat insulator is ablated and propellant is used and slag is piled up. We predicted mass change with the flight time using ground combustion data of KM composed of case, propellant, nozzle, ignitor and slag. The mass prediction of kick motor can be used for calculating the two stage mass and center of gravity history.

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Rapid Initial Detumbling Strategy for Micro/Nanosatellite with Pitch Bias Momentum System (피치 바이어스 모멘텀 방식을 사용하는 초소형 위성의 초기 자세획득 방안 연구)

  • Lee, Byeong-Hun;Choe, Jeong-Won;Jang, Yeong-Geun;Yun, Mi-Yeon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.5
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    • pp.65-73
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    • 2006
  • When a satellite separates from the launch vehicle, an initial high angular rate or a tip-off rate is generated. B-dot logic is generally used for controlling the initial tip-off rate. However, it has the disadvantage of taking a relatively long time to control the initial tip-off rate. To solve this problem, this paper suggests a new detumbling control method to be able to adapt to micro/nanosatellite with the pitch bias momentum system. Proposed detumbling method was able to control the angular rate within 20 minutes which is significantly reduced compared to conventional methods. Since the previous wheel start-up method cannot be used if the detumbling controller proposed by this paper is used, a method is also proposed for bringing up the momentum wheel speed to nominal rpm while maintaining stability in this paper. The performance of the method is compared and verified through simulation. The overall result shows much faster control time compared to the conventional methods, and achievement of the nominal wheel speed and 3-axes stabilization while maintaining stability.

Mission Performance Results of 15 CubeSats at the Contests(1st ~ 5th) and Consideration of an Improvement Scheme (큐브위성 경연대회(1~5회) 15기의 임무수행 결과 및 향상방안 고찰 )

  • Guee Won Moon;Cheol Hea Koo;In Hoi Koo
    • Journal of Aerospace System Engineering
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    • v.17 no.4
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    • pp.104-109
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    • 2023
  • The Cube Satellite Contest has been held six times as of August 2023, and a total of 21 teams have been selected. Fifteen Cube Satellites selected in previous contests were successfully launched and entered into low-Earth orbit. The six Cube Satellites selected in the sixth contest in 2022 are currently undergoing detailed design, and are scheduled to be launched in 2025 using a Korean launch vehicle. In this study, we analyzed the initial operation reports submitted by the selected teams of the Cube Satellite Contest in 2012, 2013, 2015, 2017, and 2019 to assess mission performance and identify causes of mission failure. Based on the submitted reports, an improvement scheme to enhance mission success for future Cube Satellites is proposed.

Analysis of Orbital Deployment for Micro-Satellite Constellation (초소형 위성군 궤도배치 전략 분석)

  • Song, Youngbum;Shin, Jinyoung;Park, Sang-Young;Jeon, Soobin;Song, Sung-Chan
    • Journal of Aerospace System Engineering
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    • v.16 no.2
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    • pp.63-72
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    • 2022
  • As interest in microsatellites increases, research has been actively conducted recently on the performance and use, as well as the orbital design and deployment techniques, for the microsatellite constellations. The purpose of this study was to investigate orbital deployment techniques using thrust and differential atmospheric drag control (DADC) for the Walker-delta constellation. When using thrust, the time and thrust required for orbital deployment vary, depending on the separation speed and direction of the satellite with respect to the launch vehicle. A control strategy to complete the orbital deployment with limited performance of the propulsion system is suggested and it was analyzed. As a result, the relationship between the deployment period and the total thrust consumption was derived. It takes a relatively longer deployment time using differential air drag rather than consuming thrusts. It was verified that the satellites can be deployed only with differential air drag at a general orbit of a microsatellite constellation. The conclusion of this study suggests that the deployment strategy in this paper can be used for the microsatellite constellation.

The Liability for Space Activity of Launching State of Space Object and Improvement of Korea's Space Policy (우주물체 발사국의 우주활동에 대한 책임과 우리나라 우주정책의 개선방향)

  • Lee, Kang-Bin
    • The Korean Journal of Air & Space Law and Policy
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    • v.28 no.2
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    • pp.295-347
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    • 2013
  • Korea launched the science satellite by the first launch vehicle Naro-ho(KSLV-1) at the Naro Space Center located at Oinarodo, Cohenggun Jellanamdo in August, 2009 and October, 2010. However, the first and second launch failed. At last, on January 30, 2013 the third launch of the launch vehicle Naro-ho has successfully launched and the Naro science satellite penetrated into the space orbit. Owing to the succeed of the launch of Naro-ho, Korea joined the space club by the eleventh turn following the United States, Russia, Japan and China. The United Nations adopted the Outer Space Treaty of 1967, the Rescue Agreement of 1968, the Liability Convention of 1972, the Regislation Convention of 1976, and Moon Agreement of 1979. Korea ratified the above space-related treaties except the Moon Agreement. Such space-related treaties regulate the international liability for the space activity by the launching state of the space object. Especially the Outer Space Treaty regulates the principle concerning the state's liability for the space activity. Each State Party to the Treaty that launches or procures the launching of an object into outer space is internationally liable for damage to another State Party or to its natural or judicial persons by such object or its component parts on the earth, in air space or in outer space. Under the Liability Convention, a launching state shall be absolutely liable to pay compensation for damage caused by its space object on the surface of the earth or to aircraft in flight. The major nations of the world made national legislations to observe the above space-related treaties, and to promote the space development, and to regulate the space activity. In Korea, the United States, Russia and Japan, the national space-related legislation regulates the government's liability of the launching state of the space object. The national space-related legislations of the major nations are as follows : the Outer Space Development Promotion Act and Outer Space Damage Compensation Act of Korea, the National Aeronautic and Space Act and Commercial Space Launch Act of the United States, the Law on Space Activity of Russia, and the Law concerning Japan Aerospace Exploration Agency and Space Basic Act of Japan. In order to implement the government's liability of the launching state of space object under space-related treaties and national legislations, and to establish the standing as a strong space nation, Korea shall improve the space-related policy, laws and system as follows : Firstly, the legal system relating to the space development and the space activity shall be maintained. For this matter, the legal arrangement and maintenance shall be made to implement the government's policy and regulation relating to the space development and space activity. Also the legal system shall be maintained in accordance with the elements for consideration when enacting the national legislation relevant to the peaceful exploration and use of outer space adopted by UN COPUOS. Secondly, the liability system for the space damage shall be improved. For this matter, the articles relating to the liability for the damage and the right of claiming compensation for the expense already paid for the damage in case of the joint launch and consigned launch shall be regulated newly. Thirdly, the preservation policy for the space environment shall be established. For this matter, the consideration and preservation policy of the environment in the space development and use shall be established. Also the rule to mitigate the space debris shall be adopted. Fourthly, the international cooperation relating to the space activity shall be promoted. For this matter, the international cooperation obligation of the nation in the exploration and use of outer space shall be observed. Also through the international space-related cooperation, Korea shall secure the capacity of the space development and enter into the space advanced nation.

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Propellant Consumption Estimation of Reaction Control System During Flight of KSLV-II (한국형발사체 추력기 자세제어시스템 비행 중 추진제 소모량 추정식)

  • Kang, Shin-jae;Oh, Sang-gwan;Yoon, Won-jae;Min, Byeong-joo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.7
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    • pp.529-536
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    • 2020
  • Reaction Control System of the third stage of the Korean Space Launch Vehicle II conducts roll control and 3 axis control throughout third stage engine start, satellite separation, and collision and contamination avoidance maneuver. Reaction control system consumes its propellant in each thruster operation. Hence, loading of proper amount of the propellant is important for mission success. It is needed to have a rough estimation method of propellant consumption during the flight. In this paper, we developed a energy equation using pressure and temperature data which are acquired in the on-board reaction control system. We constructed a test system which is similar with the on-board reaction control system to verify the energy equation. Test results using deionized water were compared with estimated propellant consumption. We also conducted an error analysis of the energy equation. We also presented the propellant consumption result of a system level operation test.

Development of Hydrazine Thruster Latching Valve (하이드라진 추력기 래칭 밸브 개발)

  • Yoon Ho-Sung;Chae Heon-Jung;Lee Jae-Hun;Cho Nam-Kyung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2005.11a
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    • pp.363-367
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    • 2005
  • Latching valves are operated like solenoid valves by open/close command and they maintain final open or close commend without electric power source, so they are widely used in propulsion system of satellite and launch vehicle requiring reliability and being subject of restriction of power. This paper present design and test procedure of latching valve using permanent magnet polarized solenoid, which is developed for 45N Hydrazine propulsion system, to estimate feasibility of design and manufacture of latching valve.

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Hot-Fire Test Facility for Medium-scale Monopropellant Thruster Evaluation (중대형 단일추진제 추력기 성능평가를 위한 진공연소시험설비 개발)

  • Kim, In-Tae;Lee, Jun-Hui;Lee, Jae-Won;Lee, Won-Bok;Kim, Su-Kyum;Chae, Jong-Won;Yu, Myoung-Jong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.336-339
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    • 2011
  • Hot-fire test facility is one of the most important infrastructure for thruster development and evaluation. During the past three years, Korea Aerospace Research Institute (KARI) and Hanwha Corporation have successfully performed the construction of hot-fire test facility for medium-scale monopellant thruster to the maximum 200N thrust level. In general, thruster hot-firing test should be performed in vacuum conditions to simulate space environment. The hot-fire test facility is divided into three subsystems, vacuum system, propellant supply system and data measurement & control system. The goal of this facility is to extend the capability from small thruster for satellite mission to medium-scale thruster for launch vehicle and lunar mission. In this paper, the progress and overview for thruster hot-fire test facility was introduced and test results were also presented.

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Telemetry System Encryption Technique using ARIA Encryption Algorithm (ARIA 암호 알고리즘을 이용한 원격측정 시스템 암호화 기법)

  • Choi, Seok-Hun;Lee, Nam-Sik;Kim, Bok-Ki
    • Journal of Advanced Navigation Technology
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    • v.24 no.2
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    • pp.134-141
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    • 2020
  • Telemetry system is a communication system that measures and transmits various signals in the aircraft to the ground for collecting and monitoring flight data during the development of unmanned air vehicle and satellite launch vehicles. With the recent development of wireless communication technology, it is becoming important to apply encryption of telemetry system to prepare with security threats that may occur during flight data transmission. In this paper, we suggested and implemented the application method of ARIA-256, Korean standard encryption algorithm, to apply encryption to telemetry system. In consideration of the block error propagation and the telemetry frame characteristics, frame is encrypted using the CTR mode and can apply the Reed-solomon codes recommended by CCSDS. ARIA algorithm and cipher frame are implemented in FPGA, and simulation and hardware verification system confirmed continuous frames encryption.

Evaluation of Vertical Ozone Profiles from Ozonesonde over Pohang, Korea against coinciding HALOE datasets

  • Hwang, Seung-Hyun;Sohn, Byung-Ju
    • Journal of the Korean earth science society
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    • v.27 no.7
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    • pp.778-786
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    • 2006
  • In Korea, the ozone profiles have been acquired by using ozonesonde at Pohang station of the Korea Meteorological Administration (KMA) since 1995. These ozone soundings were performed at 0500 UTC on a weekly basis (every Wednesday) in a clear sky. The ozonesonde is equipped with the model 5A ECC sensor, which is one of the most common ozonesonde systems. There have been no attempts to evaluate the Pohang ozonesonde profiles compared with satellite. This paper will provide the first evaluation results for the ozonesonde profiles against HALogen Occultation Experiment (HALOE) measurements over Korea. During 1995-2004 periods, a total of 450 and 188 ozone profiles were obtained from the ozonesonde measurements from HALOE measurements over Korea, respectively. Hence, a total of 34 coincident profile pairs are extracted. Among those total profiles, 26 profiles from ozonesonde are compared against nearly coincident HALOE measurements in time and space. For ozone profiles, the results of statistical analyses showed that the best agreement between two measurements occurs in the 20-25 km and 30-35 km region, where the mean and RMS percent differences are less than ${\pm}5$ and 14%, respectively. For temperature profiles, the mean and RMS percent differences in 20-25 km region are estimated to be about -0.1 and 1.7%, respectively. According to the scatter plots between two measurements, ozone data are strongly correlated each other above 20 km altitude range with more than 0.8 correlation coefficients. It is found that the altitude (pressure level) differences between two measurements would mainly lead to the discrepancy (over 40% below 18 km) below 20 km in ozone profiles.