• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.11
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• pp.915-920
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• 2013

Units developed for a real satellite should pass space environmental tests and launch environment tests. Thermal Vacuum Test, one of the space environmental test, simulates extreme thermal environment encountered in on-orbit operation of satellite. Many payloads which adapt non-traditional, brand-new technology are developed by developers who is not familiar to space engineering field. There might be some possibility of mistakes which result in serious problem due to lack of experience, especially from planning to performing thermal vacuum test. In this paper, brief overview of thermal environmental test related to a satellite development is summarized in order to prepare and perform the thermal test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.5
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• pp.65-71
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• 2005

Pyro-shock measurement system in launch vehicle is necessary to validate structural robustness and to prepare environmental qualification criteria for launch vehicle systems. This paper describes design, development and function test of prototype pyro-shock recorder to be employed on KSLV-I in the near future. Due to the limitation of telemetry transmission rate, pyro-shock recorder acquires and stores the shock sensor data with high sampling rate in short period and sends the data to the KSLV-I telemetry system with lower data rate. Signal conditioning in pyro-shock recorder is designed to enhance signal-to-noise ratio through proper placement of anti-aliasing filter.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.101-110
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• 2004

Flight and Qualification Models of Single Board Computer (SBC), called On-Board Computer (OBC), for HAUSAT-l picosatellite, which is scheduled to launch on September, 2004 by Russian "Dnepr" launch vehicle, have been developed. The OBC of HAUSAT-1 has been designed with some improved features compared to other picosatellites. A multifunctional controller and up-to-date SPI (Serial Peripheral Interface) and 1-Wire interface are implemented to simplify the harness routing and to minimize the mass and size of OBC. The improved fault-tolerant architecture design methodology is incorporated in the HAUSAT-1 OBC to protect against space radiation environment. The functions of the OBC were fully tested and verified by the Electrical Test Bed (ETB) model. This paper is also addressing the environmental test results, such as random vibration and thermal vacuum tests.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.1
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• pp.104-112
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• 2003

This paper introduces a thruster attitude control system for the KSR-III and addresses system configuration, design condition for several components and development systems. These systems were confirmed through environmental tests, compatibility tests with other sub-systems and are planned to launch by this year. After the launch test, it can be redesigned for optimal systems using post-analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.881-885
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• 2002

This paper presents the performance and the algorithm of a 1/3-octave band spectrum control system. The system is developed to provide various spectrums in a high intensity acoustic chamber. The required spectrum, which usually comes from launch vehicle company, starts from 25Hz band and ends 10kHz band. Automatic spectrum control system is preferred since the system requires short settling time to guarantee the safety of test objects and to reduce the amount of operating gas. The developed system adapted a PCI data-acquisition/signal-generation board installed in a personal computer to implement whole control logic. The control software used three cascade digital Butterworth filters using software. The filers are designed following ANSI S1.11 standard to implement 1/3 octave band filter bank. The graphical user interface of the system guides the user to follow standard operation procedure. The averaged control spectrum showed less than 0.05 dB in every running 1/3-octave band.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.122-129
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• 1998

본 논문에서는 실용급 위성으로는 국내에서 처음 개발되는 다목적 실용위성의 개발과정 중 준비행모델에 대한 발사환경 시험에 관련된 내용의 일부를 관련분야의 전문가들에게 소개하는데 중점을 두었다. 장시간의 개발기간과 고비용이 소요되는 위성체를 성공적으로 설정궤도에 발사하기 위해서는 소음 및 진동에 관련된 심도있는 연구가 필수적이며, 향후 우주 분야의 독자적인 기술 개발시 국내 관련분야 전문가들의 노력이 절대적으로 필요하다.

• Advances in aircraft and spacecraft science
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• v.5 no.2
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• pp.205-223
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• 2018

During launch a spacecraft is subjected to a variety of dynamical loads transmitted through the launcher to spacecraft interface or air-born transmission excitations in the acoustic pressure field inside the fairing. As a result, spacecraft are tested on ground to ensure and demonstrate the global integrity of the structure against these loads, to screen the flight hardware for quality of workmanship and to validate mathematical models. This paper addresses the numerical modelling and simulation of the low frequency sine and random vibration tests performed on electrodynamic shaker facilities to comprise the mechanical-borne transmission loads through the launcher to spacecraft interface. Consequently, the paper reviews techniques and methodologies to derive a reliable and representative coupled virtual vibration testing simulation environment based on experimental data. These technologies are explored with the main objectives to ensure a stable, reliable and accurate control while testing. As a result, the use of the derived simulation models in combination with the added value of improved control and signal processing algorithms can lead to a safer and smoother vibration test control of the entire environmental test campaign.

• Journal of the Korean Home Economics Association
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• v.39 no.7
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• pp.59-70
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• 2001

The study was designed to heap reduce daily household waste and promote the recycling of society's resources. the focus is on promoting environment-friendly activities and slevating a sense of nature-conscious domestic welfare, as well as providing wars to encourage garbage-savvy shopping, waste disposal by content and recycling. The thesis utilized demographic data obtained from 225 female homemakers and includes results based on frequency, ratio, mean, Duncan's Multiple range Test and Multiple Regression analysis. The main results are as follows: 1. Environmental consciousness appears to be higher than that of the adjustment of purchases to reduce waste and of recycling. Conversely more action seems to be taken on the waste disposal separation established since the launch of the volume-based waste collection fee system than on environmental education. 2. Homemakers with relatively higher environmental consciousness reciprocate with correspondent shopping habits, waste disposal eparation and recycling. Factors that influence daily waste reducing action include environmental consciousness homemaker employment status and the type of residence. 3. Activities reducing daily domestic wastes appear to effect a meaningful variable in explaining a sense of environmental welfare. The more respondents practice related shopping habits, waste disposal separation or recycling the more they recognize their living environment as desirable.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.185-188
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• 2008

This paper introduces the Bootstrap method for statistical analysis of noise and vibration spectrum in aeronautic and space fields. Generally, all components of a launch vehicle and its payloads are subjected to high intensive noise and vibration environment during the lift-off phase and the ascent phase through Mach =1 and Max Q. In order to verify their survivabilities against these severe vibroacoustic environments during qualification tests and acceptance tests, it is most important to estimate the proper upper limits of the environmental condition. Although NASA has typically utilized the Normal Tolerance Limit method in deriving these levels, the reference[1] says that the Bootstrap can be also an alternative method to estimate the maximum expected environments. In this paper, a general procedure of the Bootstrap method is summarized, and it is applied to analyze acceleration power spectral density functions, which were measured during acoustic test on the upper stage of KSLV-I.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1465-1469
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• 2003

In general satellite verification process, the AOCS (Attitude & Orbit Control Subsystem) should be verified through several kinds of verification test which can be divided into two major category like FBT (Fixed Bed Test) and polarity test. And each test performed in different levels such as ETB (Electrical Test Bed) and satellite level. The test method of FBT is to simulate satellite dynamics with sensors and actuators supported by necessary environmental models in ETB level. The VDS (Vehicle Dynamic Simulator) try to make the real situation as possible as the on-board processor will undergo after launch. The purpose of FBT test is to verify that attitude control logic function and hardware interface is designed as expected with closed loop simulation. The VDS is one of major equipments for performing FBT and consists of software and hardware parts. The VDS operates in VME environments with target board, several commercial boards and custom boards based on the VxWorks real time operating system. In order to make time synchronization between VDS and satellite on-board processor, high reliable semaphore was implemented to make synchronization with the interrupt signal from on-board processor. In this paper, the real-time operating environment used on VDS equipment is introduced, and the hardware and software configurations of VDS summarized in the systematic point of view. Also, we try to figure out the operational concept of VDS and AOCS verification test method with close-loop simulation.