• Journal of Satellite, Information and Communications
• /
• v.11 no.3
• /
• pp.104-109
• /
• 2016

A technology of GEO satellite communications starts from Koreasat program in Korea. Payload equipment of EQM Ku and Ka band transponders had been developed and space-qualified Ka band payload in COMS was successfully launched in June, 2010. For the purpose of military communications, Dehop-Rehop transponder was developed in Koreasat5 as ANASIS system and DAT(Digital Active Transponder) and DCAMP(Digital Channel AMPlifier) transponders are now under development. In this paper, from the study of military satellite communications trend, a direction of military communication satellite is suggested based on the current GEO SATCOM technologies in Korea. Considering the limit of frequency resources, a technology of battlefield adaptive transponder with medium capacity against high moveable jamming tactics would be efficient for the future military SATCOM system. Mid-sized military satellites with frequency hopping and mid-capacity transponders can be a solution of vitalizing the GEO satellite programs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.234-237
• /
• 2007

To protect a satellite and electronic equipment from the acoustic load generated by rocket propulsion system, many launch vehicle use acoustic blanket. Acoustic load is main source of random vibration working on the payload. Most high frequency region of the acoustic loads is reduced by payload fairing skins and acoustic blanket, but low frequency region is not. In order to reduce acoustic load of low frequency region, we designed array resonator panel which was made of composite materials. Insertion loss capacity of the payload fairing with acoustic blanket was verified from PLF acoustic test in the acoustic chamber.

• Journal of Aerospace System Engineering
• /
• v.5 no.2
• /
• pp.8-11
• /
• 2011

The scope of this paper is to show a risk management plan including how to perform risk assessment and to make a mitigation plan aspects of the communication payload system development. According to system engineering management guide of DoD of USA and risk management plan of satellite communication system, risk assessment and mitigation plan of communication payload system were performed. In this paper, it is indicated the process of risk management and risk assessment procedures as well as mathematical model for risk assessment of DoD guide. It is shown how risk assessment and mitigation plan have implemented in communication payload system development through case study.

• Journal of Aerospace System Engineering
• /
• v.16 no.3
• /
• pp.105-114
• /
• 2022

The purpose of this study was to present a conceptual design of the 6U micro-satellite system for optical image of 3 m GSD. An optical camera system with a payload of 3 m GSD image was designed and optimized. The optical system has a diameter of Ø78 mm, length 250 mm, and 1400 mm focal length. The requirement and constraints were configured for the 6U micro-satellite bus system with the payload. Satisfying the requirement and constraints, the subsystems of the 6U bus were designed such as attitude and orbit control, propulsion, command and data handling, electrical power, communication, structures and mechanisms, and thermal control subsystem. The mass budget, power budget, and communication link budget were also confirmed for the 6U micro-satellite comprising the optical payload and the subsystems of bus. To take optical images, a mission operation concept is proposed for the 6U micro-satellite in a low-Earth orbit. A constellation comprising many 6U micro-satellites studied in this paper, can provide with various data for reconnaissance and disaster tracking.

• Journal of Satellite, Information and Communications
• /
• v.7 no.3
• /
• pp.110-115
• /
• 2012

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 launch environments. The launch environments imposed on satellites are quasi-static accelerations, aerodynamic loads, acoustic loads and shock loads. Currently KARI(Korea Aerospace Research Institute) is developing Geo-KOMPSAT-2(Geostationary Earth Orbit KOrea Multi-Purpose Satellite) with technologies which were acquired during COMS(Communication, Ocean and Meteorological Satellite) development. As compared to COMS Geo-KOMPSAT-2 requires more propellant due to mass increase of Advanced Meteorological Payload with high resolution and increase of miss life, it is difficult to apply the design concept of COMS to Geo-KOMPSAT-2. This paper deals with conceptual design of Structural Subsystem for Geo-KOMPSAT-2.

• Journal of Satellite, Information and Communications
• /
• v.5 no.2
• /
• pp.8-13
• /
• 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 launch environments. The launch environments imposed on satellites are quasi-static accelerations, aerodynamic loads, acoustic loads and shock loads. Especially when optical payload is accommodated, satellite structure usually adopts the optical bench consisting of composite material not only to support and secure but also to guarantee good pointing stability against extreme thermal environments. This paper deals with optical bench and support structure which shall be designed to minimize the loads transferred to optical payloads from satellite.

• Proceedings of the KSRS Conference
• /
• 2005.10a
• /
• pp.509-511
• /
• 2005

KOMPSAT -2 equipped with an optical telescope(MSC) will be launched in this year. It can take images of the earth with push-broom scanning at altitude 685Km. Its resolution is 1m in panchromatic channel with a swath width of 15 km After the MSC is tested and the performance is measured at instrument level, it is installed on satellite. The image passes through the electro-optical system, compression and storage unit and fmally downlink sub-systems. This integration procedure necessitates the functional test of all subsystems participating in the image chain. The objective of functional test at satellite level(Quick Look test) is to check the functionality of image chain by real target image. Collimated moving image is input to the EOS in order to simulate the operational environments as if KOMPSAT -2 is being operated in orbit. The image chain from EOS to data downlink subsystem will be verified through Quick Look test. This paper explains the Quick Look test of KOMPSAT -2 and compares the taken images with collimated input ones.

• Proceedings of the KSRS Conference
• /
• v.2
• /
• pp.797-799
• /
• 2006

The Electro-optical camera subsystem as a payload of a satellite system consists of OM (optical module) and CEU(camera electronics unit), and most performances of the camera subsystem depend a lot on the CEU in which TDI CCDs(Time Delayed Integration Charge Coupled Device) take the main role of imaging by converting the light intensity into measurable voltage signal. Therefore it is required to specify and design the CEU very carefully at the early stage of development with overall specifications, design considerations, calibration definition, test methods for key performance parameters. This paper describes the overview of CEU development. It lists key requirement characteristics of CEU hardware and design considerations. It also describes what kinds of calibration are required for the CEU and defines the test and evaluation conditions in verifying requirement specifications of the CEU, which are used during acceptance test, considering the fact that CEU performance results change a lot depending on test and evaluation conditions such as operational line rate, TDI level, and light intensity level, so on.

• Aerospace Engineering and Technology
• /
• v.6 no.2
• /
• pp.87-95
• /
• 2007

The ocean and meteorological payloads of COMS are concerned to experience degration of image quality due to the disturbance induced by the motion of moving parts of the payloads. And thruster firings for stationkeeping and wheel offloading are expected to degrade the image quality of the optical payloads. In case of COMS, in order to keep the optical payload free from the mechanical interference from the other payload, the operation design approach has been taken. This paper introduces the operation design of COMS taken to avoid these problems. In order to meet users requirement by avoiding the degradation of image quality, the timeline of optical payloads and housekeeping are optimized, and operational constraints are applied to the mirror motion of the meteorological payload. This paper also introduces the results of time budget analysis performed to validate the operation design.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.807-808
• /
• 2010

To insert payload to the orbit over the 200km-altitude using launch vehicle which has 300sec the Isp, multi staging technique for launch is necessary. The range between the sea-level to the transfer orbit about 200~250km is for operation of 1st and 2nd rocket engines and the higher altitude is for propulsion system of the acceleration block and satellite. The upper stage rocket engine should have the high technology for entering the payload into the orbit precisely more than the performance for high thrust level. With this investigation of the upper stage rocket engines which have been used, we want to understand their development trend and prospect which is going to be references for the development of ours.