• Journal of the Korean Society for Railway
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• v.16 no.5
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• pp.365-371
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• 2013

This study describes impact test methods for a rolling-stock windscreen executed in Korea and Europe. Air-pressurized impact test equipment for the front windscreens of high speed trains was designed and manufactured. The equipment is capable of launching a projectile at 500km/h, in accordance with EN 15152's impact test method. Calibration of the test equipment was conducted to find an equation relating air pressure and projectile velocity. Specimens ($1000mm{\times}700mm$) having similar specifications with the front windscreens in metro and conventional trains were used to conduct impact tests with this equipment to research the impact characteristics of the screens according to the impact velocity.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.7
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• pp.575-582
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• 2018

The spaceborne cooler is applied to cool down of the focal plane of the infrared detector of the observation satellite. However, this cooler induces unnecessary micro-jitter which can degrade the image quality of the high-resolution observation satellite. In this study, we proposed a multi-layered blade type vibration isolator to attenuate micro-vibration generated from a spaceborne cooler, while assuring structural safety of the cooler under severe launch loads without an additional launch-lock device. The blade of the isolator is formed with multi-layers in order to obtain durability against fatigue failure and an adhesive is applied between each layers for granting high damping capability under launch vibration environment. In this study, the basic characteristics of the isolator were measured using the free-vibration test. The effectiveness of the isolator design was demonstrated by launch vibration test at qualification level.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.9
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• pp.929-937
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• 2008

A GPS receiver system utilized on satellite launch vehicles should operate normally under harsh environments as well as high-dynamic conditions. The GPS receiver system to use for range safety of KSLV(Korea Space Launch Vehicle)-I that is the first satellite launch vehicle developed by KARI(Korea Aerospace Research Institute) has been confirmed to survive under the environment of the launcher through extensive terrestrial tests including humidity, high and low temperatures, vacuum, sinusoidal and random vibrations, shocks, acceleration, EMI/EMC(Electromagnetic Interference/ Electromagnetic Compatibility), etc. Several performance tests have been also carried out in order to evaluate tracking capability and accuracy of the GPS receiver under high-dynamic conditions using a GPS signal simulator. Some lessons-learned during development of the GPS receiver system and its special characteristics compared with COTS(Commercial-Off-The-Shelf) GPS receiver systems are described in this paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.8
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• pp.1965-1972
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• 2015

The Missile Flight Test Launch Control System is to operate in conjunction with the Fire Control System during flight test to guided weapons. Also, this is a system for the test control and situation monitoring depending on the type of guided weapons and testing purposes. Message structure, communication protocols, such as data types for interworking with the fire control system and the Missile Flight Test Launch Control System are defined in the Launch Control ICD(Interface Control Document). ICD are composed differently of each guided weapons system and each test object. Previously, in order to interwork with the Fire Control System, the interlocking software was developed, which had a variety of problems. Therefore, we developed a new parsing algorithm in order to recognize the variety of Launch Control ICD and verified that the algorithm operates normally by checking transmitting and receiving various message in conjunction with the fire control system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.103-113
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• 2004

The satellite is exposed to the severe vibration environments such as random vibration environments such as random vibration, acceleration, shock, and acoustics during launch ascent and transportation. It is also faced with various space environments such as thermal vacuum, radiation and microgravity during the mission life. The satellite should be designed, manufactured, assembled and tested to be able to endure in these harsh environments. This paper addresses the results of the structural and thermal design and analyses for the HAUSAT-1 picosatellite which is scheduled to launch in the first quarter of 2005 by Russian launch vehicle "Dnepr". The qualification vibration and thermal vacuum tests have been conducted and passed at the satellite level to ensure that the HAUSAT-1 mechanical system was designed to be stable with enough margin.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.27-33
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• 2005

This research presents the influence of the base region modeling on the aerodynamic characteristics of a launch vehicle using CFD. The vicinity of a launch vehicle is divided into four zones, and four computational cases are made using these four zones. The aerodynamic coefficients are predicted for the angle-of-attack of 6 degrees and Mach numbers ranging from 0.4 to 2.86. It was found that modeling of the base region should not be neglected for the prediction of the aerodynamic characteristics of a launch vehicle in subsonic and transonic regions. It was also found that the modeling of the sting support used in the wind tunnel test is necessary to get a better agreement with the experiments.

• Journal of Satellite, Information and Communications
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• v.5 no.1
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• pp.80-84
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• 2010

Satellite structure should be designed to accommodate and support safely the payload and equipments necessary for its own missions and to secure satellite and payloads from severe laucnch enviroments. The lauch environments imposed on satellites are quasi-static accelerations, aerodynamic loads, acoustic loads and shock loads. To qualify the structure design against low-frequency dyanmic enviromnent, sine vibration test should be performed. During sine vibration test, the notchings are implemented in order to keep the payloads and equipments from excessive loading at their own main modes. This paper deals with sine test prediction, sine vibration test results, comparison of predicted values and tested values, and verification of Finite Element Model.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.3
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• pp.127-137
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• 2021

The launch complex(LC) is composed of various facilities. The launch control system that operates remotely those of LC spends much time and labor for developing and verifying its control algorithms. The verification of algorithms is performed by the software developer entering simulated state values based on the test procedure and checking the output result according to the algorithm flow. These verification processes should be performed repeatedly, thus the human errors are easily occurred. In this paper, an efficient automated verification method with a script test procedure is proposed to minimize human errors and shorten the verification duration. We also present the results of the algorithm verification tests for the cases of the compressed gases supply system and the electro pneumatic panel system of LC.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.1
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• pp.23-34
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• 2012

Space launch vehicles are designed to fly according to the elaborate pre-determined path. However, if a vehicle went out of the planned trajectory or its thrust terminated abnormally, or if a free-fall atmospheric reentry vehicle tracked by a tracking sensor became impossible to be measured, it is required to attempt to track by a another track equipment or estimate its impact point rapidly. In this paper a new algorithm is proposed, named the ITS-EKF combined with the Integrated Track Splitting (ITS) algorithm and the Extended Kalman Filter (EKF) to obtain the location information of a ballistic projectile without thrust, create its track and maintain it in an environment with clutter. For the reentry vehicle, the track performance is to be verified and the impact point is estimated by applying the simulation through ITS-EKF algorithm. To ensure the proposed algorithm's adequacy, by comparing the track performance and impact point distribution by the ITS-EKF with those of ITS-PF combined with ITS and Particle Filter (PF), it is confirmed that the ITS-EKF algorithm can be used an effective real-time On-line impact point prediction.

• Journal of Satellite, Information and Communications
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• v.7 no.1
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• pp.86-91
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• 2012

This paper described validation results of COMS Ka band antennas beam coverages which were developed by ETRI. After satellite launch, In Orbit Test(IOT) activities are stat to check spacecraft and payloads are still in healthy condition after launch. During IOT phase, ETRI measured radiation patterns of COMS Ka band antennas and compare with ground test(CATR) results. The antenna patterns similarity between IOT results and CATR results show that COMS Ka band antenna withstand launch vibration and in the good healthy condition. After IOT, ETRI performed field test for beam coverage measurements with vehicle to check if Ka band beam coverage are formed well as designed. For the beam coverage measurement, 17 points were selected over the Korean peninsula. The field measurement data were very similar with CATR data and this confirms that beam coverage are formed well over the Korean peninsula as expected.