• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.1
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• pp.24-32
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• 2015

Pulse tube-type spaceborne cryocooler is widely used to cool down the infrared sensor of observation satellites. However, such cryocooler also generates micro-vibration which is the one of main sources to seriously affect the image quality during its on-orbit operation. Therefore, to comply with the mission requirement of high resolution observation satellite, additional technical efforts have been required. In this study, we proposed a spaceborne cryocooler passive vibration isolator using SMA mesh washer, which guarantees the structural safety of both the micro-vibration disturbance source and itself under harsh launch vibration loads without an additional holding mechanism and the micro-vibration isolation performance on orbit environment. To verify the micro-vibration isolation performance of the proposed vibration isolator, we performed the micro-vibration isolation measurement test using the dedicated micro-vibration measurement device proposed in this study.

• Journal of Aerospace System Engineering
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• v.10 no.3
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• pp.15-22
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• 2016

The on-board appendages of satellites with mechanical moving parts such as the fly-wheel, the control-moment gyro, the cryocooler, and the gimbal-type directional antenna can generate an undesirable micro-vibration disturbance, which is one of the main causes of the image-quality degradation that affects high-resolution observation satellites. Consequently, the isolation of the micro-vibration issue has always been considered as salient, and the micro-vibration is therefore the focus of this study wherein a complex system that can provide the dual functions of a guaranteed vibration-isolation performance and electrical energy harvesting is proposed. The vibration-isolation and energy-harvesting performances of the complex system are predicted through a numerical analysis based on the characteristics that are obtained from component-level tests. In addition, the effectiveness of the complex system that is proposed in this study is verified through an assembly-level functional-performance test.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.579-587
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• 2017

Spaceborne cryocoolers produce undesirable micro-vibration disturbances during their on-orbit operation, which are a primary source of image-quality degradation for high-resolution observation satellites. Therefore, to comply with the strict mission requirement of high-quality image acquisition, micro-vibration disturbances induced by cooler operation have always been subjected to an isolation objective. However, in this study, we focused on the applicability of energy harvesting technology to generate electrical energy from micro-vibration energy of the cooler and investigated the feasibility of utilizing harvested energy as a power source to operate low-power-consumption devices such as micro-electromechanical system (MEMS) devices. A tuned mass damper (TMD)-type electromagnetic energy harvester combined with a conventional passive vibration isolator was proposed to achieve this objective. The system performs the dual functions of electrical energy generation and micro-vibration isolation. The effectiveness of the strategy was evaluated through numerical simulations.

• 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.