• Journal of Aerospace System Engineering
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• v.15 no.4
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• pp.57-63
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• 2021

The launch vehicle (LV) separation detection interface of the satellite, which is designed to initiate the launch and early operation phase (LEOP) for S-band data transmission and the solar array deployment after the LV separation, is one of the hazard items at the launch site. Therefore, this interface should satisfy the single-fault tolerance requirement for the range safety. In this paper, we discuss the LV separation detection interfaces for two different satellite launch configurations and propose a method to guarantee for the satellite to start the LEOP even under the emergency case such as a partial separation from the LV. Furthermore, the proposed method meets the range safety requirement of the launch site. As this method only changes the external harness configuration of the satellite, it increases the reliability of the satellite early operation without any modification of the existing internal logics to detect the separation event.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.29-32
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• 1999

Korea Multi-Purpose SATellite(KOMPSAT) is scheduled to be launched by TAURUS launch vehicle in November, 1999. Tracking, Telemetry and Command(TT&C) operation and the flight dynamics support should be performed for the successful Launch and Early Orbit Phase(LEOP) operation. After the first contact of the KOMPSAT spacecraft, initial orbit determination using ground based tracking data should be performed for the acquisition of the orbit. Although the KOMPSAT is planned to be directly inserted into the Sun- synchronous orbit of 685 km altitude, the orbit maneuvers are required fur the correction of the launch vehicle dispersion. Flight dynamics support such as orbit determination and maneuver planning will be performed by using KOMPSAT Mission Analysis and Planning Subsystem(MAPS) in KOMPSAT Mission Control Element(MCE). The KOMPSAT MAPS have been jointly developed by Electronics and Telecommunications Research Institute(ETRI) and Hyundai Space & Aircraft Company(HYSA). The KOMPSAT MCE was installed in Korea Aerospace Research Institute(KARI) site for the KOMPSAT operation. In this paper, the orbit determination and maneuver planning are introduced and simulated for the KOMPSAT spacecraft in LEOP operation. Initial orbit determination using short arc tracking data and definitive orbit determination using multiple passes tracking data are performed. Orbit maneuvers for the altitude correction and inclination correction are planned for achieving the final mission orbit of the KOMPSAT.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.33-36
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• 1999

The KOMPSAT, which is scheduled to be launched by Taurus launch vehicle in late November of 1999, will be in a sun-synchronous orbit with an altitude of 685km, eccentricity of 0.001, inclination of 98deg and local time of ascending node of 10:50 a.m. Electronics and Telecommunications Research Institute and Daewoo Heavy Industry had jointly developed a KOMPSAT Simulator as a component of the KOMPSAT Mission Control Element. The MCE had been delivered to Korea Aerospace Research Institute for the KOMPSAT ground operation. It is being used for training of KOMPSAT ground station personnel. Each of satellite subsystems and space environment were mathematically modeled in the simulator. To verify the overall function of KOMPSAT simulator, a Launch and Early Orbit Phase(LEOP) operation simulations have been performed. The simulator had been verified through various tests such as functional level test, subsystem test, interface test, system test, and acceptance test. In this paper, simulation results for LEOP operations to verify flight software adapted into simulator, satellite subsystem models and environment models are presented.

• Korean Journal of Remote Sensing
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• v.36 no.6_2
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• pp.1493-1507
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• 2020

The LEOP Cal/Val (Launch and Early Operation Phase Calibration/Validation) was carried out during 6 months after KOMPSAT-3A (KOMPSAT-3A Korea Multi-Purpose Satellite-3A) was launched in March 2015. After LEOP Cal/Val was successfully completed, high resolution KOMPSAT-3A has been successfully distributing to users over the past 8 years. The sub-meter high-resolution satellite image data obtained from KOMPSAT-3A is used as basic data for qualitative and quantitative information extraction in various fields such as mapping, GIS (Geographic Information System), and national land management, etc. The KARI (Korea Aerospace Research Institute) periodically checks and manages the quality of KOMPSAT-3A's product and the characteristics of satellite hardware to ensure the accuracy and reliability of information extracted from satellite data of KOMPSAT-3A. To minimize the deterioration of image quality due to aging of satellite hardware, payload and attitude sensors of KOMPSAT-3A, continuous improvement of image quality has been carried out. In this paper, the Cal/Val work-flow defined in the KOMPSAT-3A development phase was illustrated for the period of before and after the launch. The MTF, SNR, and location accuracy are the key parameters to estimate image quality and the methods of the measurements of each parameter are also described in this work. On the basis of defined quality parameters, the performance was evaluated and measured during the period of after LEOP Cal/Val. The current status and characteristics of MTF, SNR, and location accuracy of KOMPSAT-3A from 2016 to May 2020 were described as well.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.255-259
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• 2004

본 논문에서는 다목적 위성 2호의 주 탑재체인 MSC (Multi-Spectral Camera)의 영상자료 검보정을 위한 검보정 target 준비 작업에 대해 설명한다. MSC 영상 자료에 대한 검보정 작업은 다목적 위성 2호의 발사 후 초기 운영 기간 (LEOP: Launch and Early Operation Phase)인 3개월 동안 수행될 예정이다. 위성 발사 전까지 MSC 영상 자료에 대한 검보정을 수행하기 위해 필요한 준비 작업들이 현재 한국항공우주연구원에서 진행중이다. LEOP 기간 동안 MSC 영상 자료를 검보정하기 위해서, MSC의 센서 특성에 따라 7가지 정도의 검보정 target에 대한 설계 초안이 완성되었으며, 향후 target에 대한 설계를 완성한 후에 2004년 중에 한 두 부지에 몇 가지 target들을 건설하고, 다목적 위성 2호의 궤도 특성을 고려하여 일부 target은 운반이 가능하도록 제작할 예정이다. 검보정 target이 촬영된 MSC 영상 자료의 분석을 통해, GSD (Ground Sample Distance), Aliasing, Linearity, Edge Slope & Response, MTF (Modulation Transfer Function), FOV & IFOV, Absolute radiometric validation, Position Accuracy 등의 MSC 검보정 요소 값들을 측정할 계획이다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.3
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• pp.258-263
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• 2012

In this paper the Chemical Propulsion Subsystem of COMS is briefly explained and some telemetries acquired by a series operations of CPS during the Launch and Early Operation Phase of COMS are presented. The pressure and temperature of pressurant tank telemetries are compared with the results of the developed computer program. The changes in pressure are due to the two major phases. The first one is the initialization phases of CPS composed of the venting phase to vent the helium gas in the pipe network from the downstream of the propellant tanks to the thrusters for safety, the priming phase to fill the vented pipe network with oxidizer and fuel respectively and then the pressurization phase to pressurize the ullage of propellant tank to regulated pressure. And the other is the apogee engine firings in which COMS CPS is in the orbit raising phase to use helium as a pressurant to keep the pressure of propellant tank as the liquid apogee engine get fired until COMS reached to the target orbit. This program can be applicable to prepare basis design data of the next Geostationary Satellite CPS.

• Journal of Astronomy and Space Sciences
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• v.41 no.1
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• pp.43-60
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• 2024

Korea Pathfinder Lunar Orbiter (KPLO) is South Korea's first space exploration mission, developed by the Korea Aerospace Research Institute. It aims to develop technologies for lunar exploration, explore lunar science, and test new technologies. KPLO was launched on August 5, 2022, by a Falcon-9 launch vehicle from cape canaveral space force station (CCSFS) in the United States and placed on a ballistic lunar transfer (BLT) trajectory. A total of four trajectory correction maneuvers were performed during the approximately 4.5-month trans-lunar cruise phase to reach the Moon. Starting with the first lunar orbit insertion (LOI) maneuver on December 16, the spacecraft performed a total of three maneuvers before arriving at the lunar mission orbit, at an altitude of 100 kilometers, on December 27, 2022. After entering lunar orbit, the commissioning phase validated the operation of the mission mode, in which the payload is oriented toward the center of the Moon. After completing about one month of commissioning, normal mission operations began, and each payload successfully performed its planned mission. All of the spacecraft operations that KPLO performs from launch to normal operations were designed through the system operations design process. This includes operations that are automatically initiated post-separation from the launch vehicle, as well as those in lunar transfer orbit and lunar mission orbit. Key operational procedures such as the spacecraft's initial checkout, trajectory correction maneuvers, LOI, and commissioning were developed during the early operation preparation phase. These procedures were executed effectively during both the early and normal operation phases. The successful execution of these operations confirms the robust verification of the system operation.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.92.5-92
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• 2001

The KOMPSAT-1(Korea Multi-Purpose Satellite-1) is the first multi-purpose satellite funded by Korean government for the purpose of remote sensing and scientific data gathering in KOREA. It has successfully achieved its own mission since Dec. 21, 1999. This paper provides an overview of the KOMPSAT-1 missions and addresses the nominal mission planning and operation flow. This paper also describes the routine operational orbit determination and orbit prediction process using GPS navigation solution data. Meanwhile, some problems due to inexperience of the multiple mission operations during LEOP(Launch & Early Orbit Phase) and early normal mission were investigated. Then, resolutions that include the development of new mission planning tool are addressed. The KOMPSAT-1´s missions become more complicated rather than its Initially designed ones. In order to accomplish ...

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.319-326
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• 2013

This paper describes the orbital dynamics operation results for the launch and early operations phase (LEOP) of KOMPSAT-3, which was successfully launched on May 18, 2012. At the initial phase, operational orbit determination was carried out using ground tracking data and GPS navigation solution. And, both in-plane and out-of plane maneuvers were executed in order to change the orbit from the injection orbit to the mission orbit. In addition, the accuracy of precise orbit determination was indirectly evaluated by overlapping method using GPS raw data of KOMPSAT-3 and international GNSS service data from worldwide-distributed ground stations. Currently, KOMPSAT-3 is operated in pre-defined mission orbit, and its various kinds of orbit data are generated and distributed to support the normal mission operations.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.04a
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• pp.6-6
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• 2000

On-orbit thermal behavior of KOMPSAT (Korea Multi-purpose Satellite) propulsion system employing hydrazine (N$_2$H$_4$) liquid monopropellant is addressed. Thermal control performance to prevent propellant freezing in spacecraft-operational orbit was verified by flight telemetry data obtained during LEOP (Launch and Early Operation Phase). Results are depicted in terms of temperature history during several orbits selected and are compared with acceptable temperature ranges of system components. Cyclic behavior of temperature is reduced into duty cycles of the avionics heaters and subsequently converted into the electrical power required to keep away from propellant freezing. Temperature of each component which was achieved under on-ground thermal-balanced condition of spacecraft, is presented for comparison with the flight data, additionally.