• International Journal of Aeronautical and Space Sciences
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• v.11 no.4
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• pp.303-312
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• 2010

This paper introduces the upper stage attitude control system of KSLV-I, which is the first space launch vehicle in Korea. The KSLV-I upper stage attitude control system consists of two electro-hydraulic actuators and a reaction control system using cold nitrogen gas. A proportional, derivative, and integral controller is designed for the electro-hydraulic thrust vectoring system, and Schmidt trigger ON/OFF controllers are designed for the reaction control system. Each attitude controller is designed to have enough stability margins. The stability and performance of KSLV-I upper stage attitude control system is verified via hardware in the loop tests. Hardware in the loop tests are accomplished for perturbed flight conditions as well as nominal flight condition. The test results show that the attitude control loop of KSLV-I upper stage is very stable and the attitude controllers perform well for all flight conditions. Attitude controllers designed in this paper have been successfully applied to the first flight of KSLV-I on August 25, 2009. The flight test results show that all attitude controllers of the KSLV-I upper stage performed well and satisfied the accuracy specifications even during abnormal flight conditions.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.83-91
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• 2009

This paper concerns the dynamic property of TVC system in the upper stage of KSLV-I. The minimum bandwidth of TVC system is predicted by gathering and comparing the dynamic test data through whole development phases of KSLV-I. The linear models which approximate the dynamic data are also suggested. It is shown that the minimum bandwidth of KSLV-I TVC system is guaranteed over 6.0 Hz at one degree command. It is also shown that the linear model of KSLV-I TVC dynamics takes the form of the transfer function with an 8-th order denominator and a 2-nd order numerator. These results will play an important role in analyzing the flight stability and performance of KSLV-I.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.173-181
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• 2007

Radiated emission / susceptibility performance of the KSLV-I 2nd stage which are controlled from the unit level to the system level should be examined and managed all over the frequency ranges in order to ensure the normal operation of the SC, the 1st stage of the KSLV-I, ground support equipments which are installed at the space center, and other wireless communication networks. Not only unintentional electric field emissions from the KSLV-I system and its subsystems should be restricted to the levels less than the limits specified in the EMC requirements, but also proper test and evaluation method should be established, respectively. In this paper, radiated emission/susceptibility test limits, method, and test results of the KSLV-I 2nd stage engineering model are presented.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.3
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• pp.19-27
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• 2010

KSLV(Korea Space Launch Vehicle)-I is designed as a launch vehicle to enter a 100 kg-class satellite to the LEO(Low-Earth Orbit). Attitude angles of the upper-stage, including roll, pitch and yaw are controlled by cold gas thruster system using nitrogen gas. The thruster for the KSLV-I is the main pneumatic valve in the RCS(Reaction Control System). In this paper, the design, function tests, and environment tests of the thruster for KSLV-I are described. The developed thrusters are experimentally evaluated and successfully passed the required qualification and acceptance tests.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.182-188
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• 2013

This paper described flight safety center, flight safety information system(FSIS) and flight safety officer's mission and training in sequence and presented analysis's results and data processed in real-time during KSLV-I 3rd flight test. During flight safety center's operation for the 3rd flight test, monitoring of KSLV-I flight status was normally performed and the algorithms for flight safety calculations including the one for instantaneous impact point computations are also executed normally.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.183-193
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• 2008

This paper shows the results of failure mode analysis and the system-level reliability model for the flight test of KSLV-I upper stage. First, the critical 14 functions of KSLV-I upper stage are identified and the mission profile of the flight test is analyzed. Then, based on the functional analysis and the mission profile analysis, we construct a hierarchical structure of failure modes and a system-level reliability model for the flight test of KSLV-I upper stage.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.1
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• pp.94-100
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• 2006

The risk management is an organized method for identifying and measuring risk and for selecting, developing, and implementing options for the handling of risk. The risk management covers all programatic and technical factors which affect the system development performance, cost, and schedule. While technical issues are primary concern for systems engineering, the three elements(performance, cost, and schedule) must be balanced for a successful risk management process. This paper proposes the risk management process for the KSLV-I(Korea Space Launch Vehicle-I) program using computer-aided systems engineering tool, Cradle. The risk management process of KSLV-I program is similar to the general risk management process, but it has its own specific features to manage large-scale complex characteristics of KSLV-I program.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.142-150
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• 2008

In order to ensure the individual and mutual performances among the telemetry system, tracking system, flight termination system, GPS, and inertial navigation & guidance system which are installed in the KSLV-I 2nd stage and ground equipment of the Naro space center, flight test using a light airplane is required. Since the high degree of test efficiency is fulfilled through the minute plan and analysis about selection of the equipment which are applicable to the test, harness, operation strategy, and antenna installation. KSLV-I communication environment and flight profile should be precisely taken into account during the flight test. In this document, overall aspect of the KSLV-I 2nd stage equipment specification, a rack for the installation, harness, the airplane specification, and flight route which are required for the effective flight test are presented.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.161-169
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• 2008

This paper introduces test configuration and operation method for the GPS receiver system under electromagnetic test of KSLV-I upper-stage as a system qualification level and describes performance analysis of the test results. The GPS receiver system has clearly passed the electromagnetic test specifications of component level which is based on MIL-STD-461E through several design changes. Under electromagnetic test as a system qualification level, the GPS receiver system normally operates in spite of electromagnetic interferences with other systems. Performance of the GPS receiver system is also, not degraded on the condition of electromagnetic field incidence and electrostatic discharge. The KSLV-I GPS receiver system, as a result, is verified on the electromagnetic condition of the KSLV-I upper-stage.

• Aerospace Engineering and Technology
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• v.10 no.1
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• pp.13-19
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• 2011

Lift off acoustic loads of KSLV-I were predicted by the modified NASA SP-8072 source distribution method (method 2) and the result was compared with those of measurements in the flight test of KSLV-I. In the second flight test, lift off acoustic loads were measured by outer microphones attached on the cable mast. The onboard data measuring outer acoustic pressure at the interstage of KSLV-I also can be obtained. The predicted result showed very similar peak and the shape of spectrum when compared with the measured spectrum and a margin about +7 dB.