Micro Louvers for Micro and Nano-Satellites Thermal Control

2011 ◽  
Vol 317-319 ◽  
pp. 1658-1661 ◽  
Author(s):  
Sheng Zhu Cao ◽  
Xue Kang Chen ◽  
Gan Wu ◽  
Jian Ping Yang ◽  
Rui Wang
Keyword(s):  
Small Volume ◽  
Electrical Power ◽  
Actuation Voltage ◽  
Thermal Control ◽  
Environmental Condition ◽  
Device Structure ◽  
Thermal Capacitance ◽  
Low Weight ◽  
Thermal Switches ◽  
Rapid Temperature

Micro and Nano-satellites with their low thermal capacitance are vulnerable to rapid temperature fluctuations. Therefore, thermal control becomes more important, but the limitations on mass and electrical power require new approaches. Possible solutions to actively vary the heat rejection of the satellite in response to variations in the thermal load and environmental condition are the use of variable emissivity devices, such as micro louvers, micro thermal switches, etc. Micro louvers with small volume, low weight, less power consumption and large emissivity variation, will be the more suitable solution for micro and Nano-satellites thermal control. In this paper, a polyimide based micro louver is developed. The device structure was designed, the actuation voltage was analyzed theoretically and fabrication process was described. The main parameters were tested and results were presented.

Design and Fabrication of Micro-Variable Radiator

2012 ◽  
Vol 217-219 ◽  
pp. 2533-2536
Author(s):  
Sheng Zhu Cao ◽  
Xue Kang Chen ◽  
Xi Yuan Wang ◽  
Chuang Han ◽  
Jian Ping Yang
Keyword(s):  
Thermal Performance ◽  
Small Volume ◽  
Radiation Power ◽  
Actuation Voltage ◽  
Thermal Control ◽  
Dip Coating ◽  
Test Results ◽  
Uv Laser ◽  
Bulk Silicon ◽  
The Relationship

Micro-variable Radiator with its small volume, light weight and less power consumption quite meets the requirement of Micro/Nano satellite thermal control. Prototypes fabricated by bulk silicon technology have poor thermal performance owing to their confines of material and process. In this paper, a novel micro-radiator based on laser micro processing technology and polymer material was proposed, its operational principle was introduced and the relationship between structural and thermal performance was analyzed theoretically. A prototype was fabricated by UV laser micro-processing, dip-coating and magnetron sputtering technologies. Test results show that the actuation voltage is 97V and variation of radiation power is about 0.1W.

Automated observatories for geospace research in polar regions

1998 ◽  
Vol 10 (2) ◽  
pp. 192-203 ◽  
Author(s):  
J.R. Dudeney ◽  
R.I. Kressman ◽  
A.S. Rodger
Keyword(s):  
Control System ◽  
Electrical Power ◽  
Thermal Control ◽  
Climatic Conditions ◽  
Operational Experience ◽  
Polar Regions ◽  
Automated Systems ◽  
Thermal Control System ◽  
Optical Disks ◽  
Plastic Containers

The specification, development and deployment of an automated observatory designed to operate unattended for a year in the extreme climatic conditions of the polar regions is presented. Solar- and wind-powered electric generators are used to charge lead/acid batteries to provide a nominal 100 W of electrical power for operating scientific sensors. The equipment is housed in a highly insulated caboose (3m by 2m by 2m). The temperature in the latter is regulated using a unique thermal control system which utilizes the latent heat of 500 l of water stored in 25-l plastic containers. Data are logged to optical disks for collection once per year. The observatory is designed to be air-deployed using a DHC-6 aircraft. The paper discusses the rationale for designing such automated systems, the operational experience gained from several years of operation, and the application of a network of observatories to solar-terrestrial physics research.

Fabrication and Characterization of Vertical Travel Linear Microactuator

2004 ◽  
Author(s):  
Risaku Toda ◽  
Eui-Hyeok Yang
Keyword(s):  
Piezoelectric Actuator ◽  
Actuation Voltage ◽  
Silicon On Insulator ◽  
Test Bed ◽  
Device Structure ◽  
Beam Geometry ◽  
Out Of Plane ◽  
Fabrication And Characterization ◽  
Vertical Travel

This paper describes design, fabrication and characterization of a proof-of-concept vertical travel linear microactuator designed to provide out-of-plane actuation for high precision positioning applications in space. The microactuator is designed to achieve vertical actuation travel by incorporating compliant beam structures within a SOI (Silicon on Insulator) wafer. Device structure except for the piezoelectric actuator is fabricated on the SOI wafer using Deep Reactive Ion Etch (DRIE) process. Incremental travel distance of the piezoelectric actuator is adjustable at nanometer level by controlling voltage. Bistable beam geometry is employed to minimize initial gaps between electrodes. The footprint of an actuator is approximately 2 mm × 4 mm. Actuation is characterized with LabVIEW-based test bed. Actuation voltage sequence is generated by the LabVIEW controlled power relays. Vertical actuation in the range of 500 nm over 10-cycle was observed using WYKO RST Plus Optical Profiler.

scholarly journals Design and Test of Portable Hyperspectral Imaging Spectrometer

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Chunbo Zou ◽  
Jianfeng Yang ◽  
Dengshan Wu ◽  
Qiang Zhao ◽  
Yuquan Gan ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
High Performance ◽  
Small Volume ◽  
High Spatial Resolution ◽  
Flight Test ◽  
High Spectral Resolution ◽  
Imaging Spectrometer ◽  
Low Weight ◽  
Aerial Vehicle ◽  
Small Platform

We design and implement a portable hyperspectral imaging spectrometer, which has high spectral resolution, high spatial resolution, small volume, and low weight. The flight test has been conducted, and the hyperspectral images are acquired successfully. To achieve high performance, small volume, and regular appearance, an improved Dyson structure is designed and used in the hyperspectral imaging spectrometer. The hyperspectral imaging spectrometer is suitable for the small platform such as CubeSat and UAV (unmanned aerial vehicle), and it is also convenient to use for hyperspectral imaging acquiring in the laboratory and the field.

Specific Heat Measurements of Ti6Al4V/Nano SiCp Composite

2017 ◽  
Vol 14 (1) ◽  
pp. 742-746
Author(s):  
S Krishnamohan ◽  
S Ramanathan ◽  
V Ramakrishnan
Keyword(s):  
Heat Capacity ◽  
Weight Ratio ◽  
Thermal Control ◽  
Ti6al4v Alloy ◽  
Thermal Design ◽  
Thermal Method ◽  
Scanning Calorimetry ◽  
Low Weight ◽  
Wide Range ◽  
Materials Used

The elevated strength, low weight ratio and excellent corrosion resistance intrinsic to titanium and its alloys has led to a wide range of successful applications which ensures high levels of unswerving performance in aerospace. The performance of the Thermal Control System extremely depends on the thermal behavior of the materials used in its elements. The measurements of the thermal properties of materials are necessary for better understanding of the thermal design. Differential scanning calorimetry (DSC) is the most extensively used thermal method for finding wealth of information about a material. The heat capacity (Cp) of a material was established quantitatively using DSC. The measurement was made by heating a very small quantity of the Ti6Al4V alloy and Ti6Al4V/Nano SiCp composites. Mechanical alloying (MA) and Powder metallurgy (P/M) techniques were used to fabricate the Ti6Al4V alloy and Ti6Al4V/ nano SiCp composites. The heat flow reaction was recorded as a function of definite sample temperature range from −100 °C to 375 °C. The measurements of the heat capacity of each sample in three runs were recorded by DSC. The heat capacity (Cp) of specimens is reported in this study.

Organic photovoltaic module development with inverted device structure

2015 ◽  
Vol 1737 ◽  
Author(s):  
Shigehiko Mori ◽  
Haruhi Oh-oka ◽  
Hideyuki Nakao ◽  
Takeshi Gotanda ◽  
Yoshihiko Nakano ◽  
...  
Keyword(s):  
Electrical Power ◽  
Organic Photovoltaic ◽  
Thickness Variation ◽  
Photovoltaic Module ◽  
Device Structure ◽  
Solar Cell Efficiency ◽  
Cell Efficiency ◽  
Module Design ◽  
Coating Method ◽  
Module Development

ABSTRACTThe power conversion efficiency (PCE) of organic photovoltaic (OPV) modules with 9.5% (25 cm2) and 8.7% (802 cm2) have been demonstrated. This PCE of the module exceeded our previous world records of 8.5% (25 cm2) and 6.8% (396 cm2) that were listed in the latest Solar Cell Efficiency Tables ver.43 [1]. Both module design and coating/patterning technique were consistently studied for module development. In order to achieve highly efficient modules, we increased the ratio of photo-active area to designated illumination area to 94% without any scribing process and placed insulating layers in order to decrease the leakage current. The meniscus coating method was used for the fabrication of both buffer and photoactive layers. This technique ensures the fabrication of uniform and nanometer order thickness layers with thickness variation less than 3%. Furthermore, the PCE of the OPV under indoor illumination was found to be higher than that of the conventional Si type solar cells. This indicates that OPVs are promising as electrical power supplies for indoor applications. Therefore, we have also developed several prototypes for electronics integrated photovoltaics (EIPV) such as electrical shelf labels and wireless sensors embedded with our OPV modules, which can be operated by indoor lights.

A Variable-Emittance Radiator Based on a Metal-Insulator Transition of (La,Sr)MnO3

2002 ◽  
Vol 755 ◽  
Author(s):  
Yuichi Shimakawa ◽  
Tsutomu Yoshitake ◽  
Yoshimi Kubo ◽  
Takahiko Machida ◽  
Kiminari Shinagawa ◽  
...  
Keyword(s):  
Production Cost ◽  
Electrical Power ◽  
Thermal Control ◽  
Insulator Transition ◽  
Infrared Reflectance ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Control Devices ◽  
High Emissivity ◽  
Low Emittance

ABSTRACTVariable-emittance radiators based on the metal-insulator transition of (La,Sr)MnO3 have been developed. The emittance property of the material was evaluated from infrared reflectance spectra; that is, (La,Sr)MnO3 shows low emittance at low temperature but high emittance at high temperature. Moreover, the emittance property significantly changes at the metal-insulator transition temperature, where the material changes from a highly reflective (i.e., low emissivity) metal to a less reflective (i.e., high emissivity) insulator. The (La,Sr)MnO3 thin-films fitted on a spacecraft surface can, therefore, be used to automatically control the emmisive heat transfer from the spacecraft without the need for electrical power. The developed (La,Sr)MnO3 thin-film radiator also greatly reduces the weight and production cost of the thermal control devices.

Harnessing Dielectric Breakdown of Dielectric Elastomer to Achieve Large Actuation

2017 ◽  
Vol 84 (12) ◽  
Author(s):  
Hui Zhang ◽  
Yingxi Wang ◽  
Hareesh Godaba ◽  
Boo Cheong Khoo ◽  
Zhisheng Zhang ◽  
...  
Keyword(s):  
Large Deformation ◽  
Volume Change ◽  
Loading Condition ◽  
Small Volume ◽  
Dielectric Breakdown ◽  
Dielectric Elastomer ◽  
Flight System ◽  
Actuation System ◽  
Low Weight ◽  
Open Question

It is an interesting open question how to achieve large actuation of a dielectric elastomer (DE). In many previous works, in order to harness snap-through instability to achieve large deformation, a reservoir was employed to assist the dielectric elastomer actuator (DEA) to optimize its loading condition/path, which makes the whole actuation system bulky and heavy. In this paper, we explore large actuation of a DE balloon with applications to a soft flight system. The balloon consists of two separate DEAs: The inner one is stiffer while the outer one is softer. The whole actuation system has a small volume and a low weight, but can achieve large actuation by harnessing dielectric breakdown of the inner elastomer. The volume induced by dielectric breakdown is more than 20 times the voltage-induced volume change of DEAs. The experiments demonstrate a soft flight system, which can move effectively in air by taking advantage of large actuation of this DE balloon. This project also shows that failure of materials can be harnessed to achieve useful functionalities.

Study on the Characterization and Bending Performance of Electro-Active Actuator Based on Cellulose and Poly(3-Hydroxybutyrate)

2011 ◽  
Vol 298 ◽  
pp. 45-50
Author(s):  
Cheng Wei Hou ◽  
Zhi Jiang Cai
Keyword(s):  
Electrical Power ◽  
Actuation Voltage ◽  
Bending Performance ◽  
Blend Film ◽  
Humidity Condition ◽  
Lifetime Test ◽  
Long Lifetime ◽  
Electrical Power Consumption ◽  
Free Bending ◽  
Actuator Performance

This paper describes a new electro-active actuator based on cellulose and poly(3-hydroxybutyrate) (PHB) blend film that can produce high bending displacement in room humidity condition. Cellulose based actuator has been reported as a smart material that has merits in terms of lightweight, dry condition, biodegradability, sustainability, large displacement output and low actuation voltage. However, its actuator performance is very sensitive to humidity, which requires high humidity condition for the maximum actuator performance. To overcome this drawback, we introduce cellulose-PHB blend film based actuator. To fabricate this new actuator, cellulose and PHB were dissolved in trifluoroacetic acid. The solution was cast to form a film followed by depositing thin gold electrode on both sides of the film. The morphology of the blend was characterized by scanning electron microscopy. The actuator can be actuated under AC voltage. The bending performance was evaluated in terms of free bending displacement, electrical power consumption output with respect to voltage and frequency and lifetime test at ambient condition. Primary results show that this cellulose- PHB blend actuator is less sensitive to humidity and it shows much high bending displacement and long lifetime (more than 10 hours) at room humidity condition. These results indicate that this new cellulose-PHB blend actuator is promising for many biomimetic applications in foreseeable future.

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