• Aerospace Engineering and Technology
• /
• v.10 no.2
• /
• pp.29-36
• /
• 2011

The Science and Technology Satellite-3 (STSAT-3) is based on the KITSAT-1, 2, 3 and STSAT-1, 2 which were Korea micro-satellites for the mission of space and earth science. The objectives of the STSAT-3 are to support earth and space sciences in parallel with the demonstration of spacecraft technology. The STSAT-3 carries an infrared (IR) camera for space & earth observation and an imaging spectrometer for earth observation. The IR payload instrument of the STSAT-3, Multi-purpose Infrared Imaging System (MIRIS), will observe the Galactic plane and North/South Ecliptic poles to research the origin of universe. The secondary payload instrument, Compact Imaging Spectrometer (COMIS), images the Earth's surface. The data acquired from COMIS are expected to be used for various application fields such as monitoring of disaster management, water quality studies, and farmland assessment. In this paper we present the operations concept of STSAT-3 which will be launched into a sun-synchronous orbit at a nominal altitude of 600km in late 2012.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.4
• /
• pp.627-633
• /
• 2000

In this paper, new printed-type inverted F antenna is designed and fabricated to gain the ideal radiation pattern of a rocket-borne antenna which is expected to show the omni-directional pattern characteristic in rear direction. The radiation pattern of this antenna is measured in condition that the antenna is mounted on the side of the fin which is located on the tail of a rocket or a missile. Measurement result shows that the improved symmetrical radiation pattern is obtained with respect to the radiation pattern of the existing inverted F antenna. Besides parasite element which can be operated as reflector is attached in front of the antenna with the distance between the antenna and the parasite element $\lambda$/8. The result shows that the ratio of the front to the rear radiation level is improved by 8 dB.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.1
• /
• pp.67.2-67.2
• /
• 2012

경희대학교와 UC Berkeley, Imperial College London은 우주관측을 위한 초소형 인공위성인 TRIO-CINEMA(TRIO-CINEMA) Project를 수행하고 있다. TRIO-CINEMA는 총 3기의 인공위성으로 경희대학교에서 2기의 위성을, UC Berkeley에서 1기의 위성을, Imperial College에서 3개의 자력계를 제작하고 있다. CINEMA는 Cubesat의 3U 규격으로 크기는 $100mm{\times}100mm{\times}340.5mm$이고 무게는 약 3 kg, 소비전력은 약 3 W이며, 지구 주변의 ENA측정을 위한 주 탑재체인 STEIN(SupraThermal Electrons, Ions, and Neutrals)과 자기장 측정을 위한 부 탑재체인 MAGIC(MAGnetometer from Imperial College)이 탑재되어 약 1년간 800 km 태양동주기 궤도에서 임무를 수행할 예정이다. 위성의 발사는 별도의 POD(Picosatellite Orbital Deployer)라는 Adaptor를 사용해 발사체에 탑재되는데, 발사환경에서 위성이 받을 모든 현상에 관하여 NX Nastran을 사용해 계산을 진행하였다. 계산 결과의 검증을 위해 위성의 Structure Model을 가지고 Random Vibration test를 수행해 위성의 고유 진동수를 측정하였다. 또한 위성이 궤도에서 운용 중 다양하게 받게 되는 열원에 따른 위성의 각 부분의 온도변화를 NX TMG program을 사용하여 계산하였다. 계산 결과의 검증을 위해 3월 Thermal Cycle test 및 Thermal Balance test를 수행할 예정이다. UC Berkeley에서 제작한 위성 1기는 제작완료 후 발사를 위해 발사장으로 배송을 완료하였고, 경희대학교에서 제작 중인 CINEMA 위성 2기는 2012년 후반기 러시아에서 Dnepr 로켓을 사용해 발사 예정이다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.2A
• /
• pp.194-200
• /
• 2006

A 26.4 GHz phase locked oscillator(PLO) for communication satellite transponder is developed. The PLO consists of fundamental frequency generation module(FFGM) and frequency multiplication part(FMP). The signal of 26.4 GHz is generated through frequency tripling process of 8.8 GHz fundamental frequency. Phase locking technique using sampling phase detector(SPD) is adopted to design the FFGM. The MMIC tripler and amplifier are also designed for the reduction of the size and mass of FMP. The phase noise characteristics are exhibited as -96 dBc/Hz at 10 tHz offset frequency and -105 dBc/Hz at 100 kHz offset frequency, respectively, with the output power over 11 dBm. All performance parameters are complied with the design requirements.

• Journal of Aerospace System Engineering
• /
• v.11 no.1
• /
• pp.1-7
• /
• 2017

While a satellite is carried into orbit by a launch vehicle, it is exposed to the severe launch environment with random vibrations and shock. Accordingly, these vibration sources affect electronic equipment, particularly the printed circuit board (PCB) in the satellite. When the launch load impacts the PCB, it causes negative behavior. This causes perpendicular bending around the boundary of fixation points that finally leads to the failure of solder joints, lead wires, and PCB cracks. To overcome these issues, the electronic equipment design must meet reliability requirements. In this paper, Steinberg's method is used to derive allowable and maximum deflection to verify design from a life perspective concerning the control board of the Antenna Pointing Driver (APD) mounted on KOMPSAT-3.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.4
• /
• pp.363-368
• /
• 2007

Lithium-ion batteries providing high gravimetric energy density are rapidly replacing Ni-Cd and Ni-H2 in aerospace applications. The main advantage is the weight reduction of the battery system. Weight is a major concern in aerospace applications. Also, lithium-ion offer low thermal dissipation, high energy efficiency, and low cell cost. The Onboard battery module for KSLV-I(Korea Space Launch Vehicle) contains 80 Sony US18650 cells configured as 10 strings in parallel, with each string containing 8 series connected cells. This allows to meet voltage and capacity requirements specified for the mission. In this paper design description and specifications of lithium-ion battery developed are presented. Qualification test flow is also shown to make sure the performance in the predicted space environment. Electrical performance was simulated by dedicated program, and verified with electronic load. Lastly, the capacity was proven on real equipment load assembly.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.8
• /
• pp.36-43
• /
• 2003

In this study, a satellite payload module was optimized by considering local stabilities. As design constraints in the satellite structure, local instabilities such as wrinkling, dimpling, crippling for honeycomb structures and crippling failure mode for beams were considered in addition to frequency and stress constraints. The constraints for the local instabilities (uncommon in general structures) were taken for the optimization of a satellite structures under severe launching environments. The analysis was performed combining the finite element analysis and optimization program. From the optimization results, it was found that frequency, crippling and wrinkling were the most critical constraints to achieve the design goals. Also, the importance of each design variable was estimated. Finally, the optimum design of the payload module was achieved for various design constraints and design parameters.

• Aerospace Engineering and Technology
• /
• v.6 no.1
• /
• pp.114-119
• /
• 2007

This paper introduces modal test of the 2nd stage structure of KSLV-I which is composed to satellite, PLA(Payload Adapter), EB(Equipment Bay), KMS(Kick Motor Support) and KM(Kick Motor) without PLF(Payload Fairing). In this test, to simulate free-free boundary condition, test object was hung by 4 bungee cords and excited by using impact hammer. From this test, dynamic properties of the 2nd stage structure of KSLV-I can be obtained. Modal test data are analyzed by using TDAS(Test Data Analysis Software). As the result, modal parameters and mode shapes below 100Hz of the 2nd stage of KSLV-I were identified.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.10
• /
• pp.105-111
• /
• 2003

A measurement of spacecraft alignment is an important process of spacecraft assembly, integration and test. Because, it is necessary that a operator of a ground station controls the precise positions of on-orbit spacecraft by using the alignment data of attitude orbit control sensors(AOCS) on spacecraft. And, an accuracy of spacecraft alignment requirement is about $0.1^{\circ}{\sim}0.7^{\circ}$. A spacecraft alignment is measured by autocollimation of theodolite. This paper describes the measurement principle and method of spacecraft alignment. The result shows that all the AOCS on the spacecraft are aligned within the tolerance required through the alignment measurement.

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.2
• /
• pp.87.3-88
• /
• 2017

한국천문연구원은 차세대소형위성 1호의 근적외선 영상분광기 NISS (Near-infrared Imaging Spectrometer for Star formation history) 탑재체를 개발하여 2017년 6월 30일에 최종 비행모델을 납품하였고, 이 발표는 탑재체 NISS 구조체의 비행모델 개발 결과를 보고한다. NISS는 0.9 - 2.5um (R~20) 근적외선 파장에서 관측을 해야 하기 때문에, 구조체의 배경잡음을 없애기 위해서 200K까지 passive cooling으로 냉각되며, H2RG 검출기는 소형 냉동기에 의해 약 88K에서 운영된다. NISS 구조체의 passive cooling을 효율적으로 수행하기 위해서 방열판, Kevlar 지지대, MLI, 표면제어용 필름 등을 조립하였고, 실제 지상 시험을 통해서 그 성능을 확인하였다. NISS 구조체는 최종 시스템 조립 과정에서 전자부 하네스 조립을 함께 수행했으며, 온도 모니터링 센서를 부착하고 소형 냉동기 피드백 온도를 반복 시험을 통해서 결정하였다. NISS 구조체는 미러 및 렌즈를 지지하는 광기계부를 함께 포함하기 때문에 발사 및 우주환경에서 광학 성능을 유지하기 위한 설계를 거쳐서 제작 되었으며, 최종 시스템 검교정 시험, 진동 및 열진공 시험을 통해서 그 성능을 확인하였다. NISS를 탑재한 차세대소형위성 1호는 2018년 상반기에 미국의 Falcon 9 발사체에 실려서 발사될 예정이다.