• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1236-1240
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• 2004

Thermal vacuum test for satellites should be performed before launch to verify the feasibility of satellites' operation in a harsh space environment which is represented as an extremely cold temperature and vacuum condition. A large space simulator(${\Phi}8m{\times}L10m$) has been demanded to accomplish the thermal vacuum test for the huge satellites designed in compliance with the national space program of Korea. In this paper, the design and calculation of thermal shroud which is the core part of large space simulator were discussed. The characteristics of the large space simulator being constructed at Korea Aerospace Research Institute(KARI) were depicted.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.42-42
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• 2003

Satellite formation flying is the placing of multiple satellites into nearby orbits to form 'clusters' of satellites. These clusters of satellites usually work together to accomplish a mission. There are many benefits to using multiple satellite as opposed to one large satellites such as increasing productivity. reducing mission and launch cost. Hill's equations are useful to describe the relative motion of two satellites in formation flying, however. the disturbance forces acting on satellites is not considered in that equations. In this paper, a method for maintaining the relative distance between satellites is presented, which used mean orbital elements considering J2 perturbation. Control design process is also presented for minimizing total fuel consumption.

• Journal of Advanced Navigation Technology
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• v.21 no.3
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• pp.213-219
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• 2017

Large satellite development programs might take decades to build, launch and operate in space environments at costs in excess of a billion dollars. However, small satellites can reduce the costs not only by using commercial software and sensors, but also by shortening the development period to two years or less. In this paper, we discuss the development status of small satellites, and propose some military applications of small satellites. First, we describe the industrial trends of small satellites in advanced countries such as the United States and Japan. Also, we describe the development status of small satellites in Korea. Military applications are largely classified into education, research, and operational purposes. Small satellites are developing rapidly in commercial markets and they will play an important role in military sector. Therefore, the military should consider small satellites as important strategic assets in future conflicts and provide means to develop them.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.7
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• pp.1014-1018
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• 2012

This paper presents a decentralized controller design for formation flying of multiple satellites based on the overlapping decomposition technique. Each satellite is assumed to avail only the information of its own and in front of itself, which restricts the structure of a controller gain matrix to an overlapped form. The concerned large-scale system is expanded using the overlapping decomposition technique. Design condition is represented in terms of linear matrix inequalities with small-scale systems in a decentralized form, based on the expanded system. The resulting controller is contracted to the original overlapped form so as to close the original system. A numerical simulation shows the effectiveness of the proposed technique.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.1
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• pp.98-106
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• 2018

With the advancement in technology, miniaturization, integration, and weight reduction of satellite components have become possible. In this regard, existing medium and large satellites have been replaced by small satellites. As the demand for small satellites increases, the need for micro-thrusters has emerged for precise attitude and position control. A laser ablation micro-thruster, which generates thrust by using ablation jets that offer a wide range of thrusts and low-impulse thrusts, is considered as an alternative for micro-thrusters in small satellites. The objective of the present study is to introduce configurations of the laser ablation micro-thruster and its research trend.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.1
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• pp.84-90
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• 2006

The formation flying of satellites has been identified as an enabling technology for many future space missions. The application of conventional thrusters for formation flying usually results in high cost, limited life-time, and a large weight penalty. Various methods including the use of coulomb forces have been considered as an alternative to the conventional thrusters. In the present investigation, we investigate the feasibility of achieving the desired formation using Coulomb forces. This method has several advantages including low cost, light weight and no contamination. A simple controller based on the relative position and velocity errors between the leader and follower satellites is developed. The proposed controller is applied to circular formations considering the effects of disturbances in initial formation conditions as well as system nonlinearity. Results of the numerical simulation state that the proposed controller is successful in establishing circular formations of leader and follower satellites, for a formation size below 100 m.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.753-756
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• 2017

With the advancement of technology, miniaturization, integration, and weight reduction have become possible, and the existing medium and large satellites have been replaced by small satellites, and the need for a micro thruster has emerged. Laser ablation micro-thruster is a new type thruster using laser ablation. It is emerging as a new candidate in micro-thrusters with wide thrust range and low single impulse thrust. The objective of present study is to introduces the structure, propellant, and research trends of the laser ablation micro-thruster.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.8
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• pp.605-612
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• 2013

When developing medium satellites or large satellites, coupled load analysis(CLA) is performed in order to verify satellite design as a final assessment under launch environment. Maximum acceleration, gap between adjacent parts, internal loads obtained from CLA are used to assess the safety of satellite design by comparing them with the allowable loads of every component. To achieve reliable CLA results, satellite FE model have to be properly updated to match with the sine vibration test results. In this paper, the validation procedure of satellite FE model and its results are discussed.

• Advances in aircraft and spacecraft science
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• v.9 no.4
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• pp.279-300
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• 2022

This paper analyzes the possibilities of a new method to using TLE data for detecting satellite maneuvers. The method has a number of advantages over other methods that are designed to detect maneuvers. It allows not only to detect maneuvers, but also to get a more complete picture of the maneuver. In particular, the method makes it possible to estimate the moments of the beginning and end of the maneuver, calculate the changes in the orbital elements, evaluate the tangential and binormal components of the impulse, and finally, calculate the impulse of the satellite obtained as a result of the maneuver. To demonstrate in detail the capabilities of the algorithm, the proposed method was applied to one of LEO satellites - TIANHUI-1 satellite. After the efficiency of the method was proved, this method was applied to the China Space Station - TIANHE-1 (CSS), Starlink-1095 and Starlink-2305 satellites. The maneuvers of the CSS and Starlink-1095 satellite during their close encounter on 1 July, 2021, and the CSS and Starlink-2305 satellite during their close encounter on 21 October, 2021 are analyzed in detail. The minimum distances between the CSS and Starlink satellites at the moments of their maximum approaches are estimated. An estimate of the computation time of this algorithm is given, and the possibility of its use for monitoring maneuvers or other anomalous orbital changes of a large number of satellites in near real-time is shown. It is assumed that on the basis of this method, a service for monitoring satellite maneuvers can be created.

• Proceedings of the Optical Society of Korea Conference
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• 2002.11a
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• pp.106-107
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• 2002