Pub Date : 2007-03-03DOI: 10.1109/AERO.2007.352779
L. Pinsky, J. Chancellor
A new solid state detector, known as Medipix, developed by a consortium of academic institutions has been evolved from a technology originally created for use at the LHC at CERN in Geneva, Switzerland. This technology is being harnessed for use as an active personal dosimeter for space radiation applications. The pixel based technology embeds the entire required readout electronics for each pixel withing the pixel's 55 micron square footprint. That allows the seamless tiling of multiple arrays of detectors. Prototypes have been exposed to heavy ion beams at the HIMAC facility in Japan and at the Texas A&M cyclotron in the US. The results are very encouraging. Extensive experience is being gained in using the detectors with appropriate converters for simultaneous neutron dosimetry as well. Ultimate versions may be deployed that are both wireless and self-contained, as well as having a package size comparable to current passive personal dosimeters. Prospect are excellent for building them into spacesuits, which would provide ground-based real-time monitoring of the detailed doses being taken by crew members during such high-risk periods as EVAs. These dosimeters could also be used as active area monitors in a variety of both space and ground-based applications.
{"title":"Development of a New Active Personal Dosimeter for Use in Space Radiation Environments","authors":"L. Pinsky, J. Chancellor","doi":"10.1109/AERO.2007.352779","DOIUrl":"https://doi.org/10.1109/AERO.2007.352779","url":null,"abstract":"A new solid state detector, known as Medipix, developed by a consortium of academic institutions has been evolved from a technology originally created for use at the LHC at CERN in Geneva, Switzerland. This technology is being harnessed for use as an active personal dosimeter for space radiation applications. The pixel based technology embeds the entire required readout electronics for each pixel withing the pixel's 55 micron square footprint. That allows the seamless tiling of multiple arrays of detectors. Prototypes have been exposed to heavy ion beams at the HIMAC facility in Japan and at the Texas A&M cyclotron in the US. The results are very encouraging. Extensive experience is being gained in using the detectors with appropriate converters for simultaneous neutron dosimetry as well. Ultimate versions may be deployed that are both wireless and self-contained, as well as having a package size comparable to current passive personal dosimeters. Prospect are excellent for building them into spacesuits, which would provide ground-based real-time monitoring of the detailed doses being taken by crew members during such high-risk periods as EVAs. These dosimeters could also be used as active area monitors in a variety of both space and ground-based applications.","PeriodicalId":6295,"journal":{"name":"2007 IEEE Aerospace Conference","volume":"25 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2007-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78292338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-03-03DOI: 10.1109/AERO.2007.352716
Hanbing Song, C. Underwood
In this paper, we propose the use of a novel fixed-wing vertical take-off and landing (VTOL) aerobot. A mission profile to investigate the Isidis Planitia region of Mars is proposed based on the knowledge of the planet's geophysical characteristics, its atmosphere and terrain. The aerobot design is described from the aspects of vehicle selection, its propulsion system, power system, payload, thermal management, structure, mass budget, and control strategy and sensor suite. The aerobot proposed in this paper is believed to be a practical and realistic solution to the problem of investigating the Martian surface. A six-degree-of-freedom flight simulator has been created to support the aerobot design process by providing performance evaluations. The nonlinear dynamics is then linearized to a state-space formulation at a certain trimmed equilibrium point. Basic autopilot modes are developed for the aerobot based on the linearized state-space model. The results of the simulation show the aerobot is stable and controllable.
{"title":"A Mars VTOL Aerobot - Preliminary Design, Dynamics and Control","authors":"Hanbing Song, C. Underwood","doi":"10.1109/AERO.2007.352716","DOIUrl":"https://doi.org/10.1109/AERO.2007.352716","url":null,"abstract":"In this paper, we propose the use of a novel fixed-wing vertical take-off and landing (VTOL) aerobot. A mission profile to investigate the Isidis Planitia region of Mars is proposed based on the knowledge of the planet's geophysical characteristics, its atmosphere and terrain. The aerobot design is described from the aspects of vehicle selection, its propulsion system, power system, payload, thermal management, structure, mass budget, and control strategy and sensor suite. The aerobot proposed in this paper is believed to be a practical and realistic solution to the problem of investigating the Martian surface. A six-degree-of-freedom flight simulator has been created to support the aerobot design process by providing performance evaluations. The nonlinear dynamics is then linearized to a state-space formulation at a certain trimmed equilibrium point. Basic autopilot modes are developed for the aerobot based on the linearized state-space model. The results of the simulation show the aerobot is stable and controllable.","PeriodicalId":6295,"journal":{"name":"2007 IEEE Aerospace Conference","volume":"144 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"2007-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77512455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-03-03DOI: 10.1109/AERO.2007.353079
G. Serabyn
The direct detection of faint planetary companions to bright nearby stars calls for the development of high-contrast narrow-field detection techniques. A number of novel coronagraphic approaches aimed at filling this niche have recently been proposed, but this challenging observational goal may also call for the development of novel types of telescope architecture. As discussed here, one approach to high-contrast narrow field imaging involves replacing the monolithic telescope assembly by an array of small "sub-aperture" telescopes, with the final pupil being assembled by means of a single-mode fiber array. Such an approach can potentially greatly relax the volume, mass and cost constraints thought to apply to large and accurately-figured monolithic telescopes. However, the suggested approach relies on the use of a well-matched, low-dispersion, single-mode fiber array. Classical single mode fibers would require dispersion correction to match pathlengths, but the new generation of photonic fibers, with design-selectable parameters, may ease this issue.
{"title":"High-Contrast, Narrow-Field Imaging with a Multi-Aperture Telescope","authors":"G. Serabyn","doi":"10.1109/AERO.2007.353079","DOIUrl":"https://doi.org/10.1109/AERO.2007.353079","url":null,"abstract":"The direct detection of faint planetary companions to bright nearby stars calls for the development of high-contrast narrow-field detection techniques. A number of novel coronagraphic approaches aimed at filling this niche have recently been proposed, but this challenging observational goal may also call for the development of novel types of telescope architecture. As discussed here, one approach to high-contrast narrow field imaging involves replacing the monolithic telescope assembly by an array of small \"sub-aperture\" telescopes, with the final pupil being assembled by means of a single-mode fiber array. Such an approach can potentially greatly relax the volume, mass and cost constraints thought to apply to large and accurately-figured monolithic telescopes. However, the suggested approach relies on the use of a well-matched, low-dispersion, single-mode fiber array. Classical single mode fibers would require dispersion correction to match pathlengths, but the new generation of photonic fibers, with design-selectable parameters, may ease this issue.","PeriodicalId":6295,"journal":{"name":"2007 IEEE Aerospace Conference","volume":"28 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2007-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77777697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-03-03DOI: 10.1109/AERO.2007.352787
L. Herrell
Space technology experiments and validation missions share a common dilemma with the aerospace industry in general: the high cost of access to space. Whether the experiment is a so-called university cubesat, a university measurement experiment, or a NASA New Millennium Program (NMP) technology validation mission, the access to space option can be scaled appropriately for the particular constraints. A cubesat might fly as one of a number of cubesats that negotiate a flight on an experimental vehicle. A university experiment might do the same. A NASA flight validation might partner with an Air Force experimental mission.
{"title":"Access to Space for Technology Validation Missions: A Practical Guide","authors":"L. Herrell","doi":"10.1109/AERO.2007.352787","DOIUrl":"https://doi.org/10.1109/AERO.2007.352787","url":null,"abstract":"Space technology experiments and validation missions share a common dilemma with the aerospace industry in general: the high cost of access to space. Whether the experiment is a so-called university cubesat, a university measurement experiment, or a NASA New Millennium Program (NMP) technology validation mission, the access to space option can be scaled appropriately for the particular constraints. A cubesat might fly as one of a number of cubesats that negotiate a flight on an experimental vehicle. A university experiment might do the same. A NASA flight validation might partner with an Air Force experimental mission.","PeriodicalId":6295,"journal":{"name":"2007 IEEE Aerospace Conference","volume":"97 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2007-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77917480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-03-03DOI: 10.1109/AERO.2007.352800
Dan Shen, Genshe Chen, Jose B Cruz, C. Kwan, M. Kruger
In an adversarial military environment, it is important to efficiently and promptly predict the enemy's tactical intent from lower level spatial and temporal information. In this paper, we propose a decentralized Markov game (MG) theoretic approach to estimate the belief of each possible enemy course of action (ECOA), which is utilized to model the adversary intents. It has the following advantages: (1) It is decentralized. Each cluster or team makes decisions mostly based on local information. We put more autonomies in each group allowing for more flexibilities; (2) A Markov decision process (MDP) can effectively model the uncertainties in the noisy military environment; (3) It is a game model with three players: red force (enemies), blue force (friendly forces), and white force (neutral objects); (4) Correlated-Q reinforcement learning is integrated. With the consideration that actual value functions are not normally known and they must be estimated, we integrate correlated-Q learning concept in our game approach to dynamically adjust the payoffs function of each player. A simulation software package has been developed to demonstrate the performance of our proposed algorithms. Simulations have verified that our proposed algorithms are scalable, stable, and satisfactory in performance.
{"title":"An Adaptive Markov Game Model for Threat Intent Inference","authors":"Dan Shen, Genshe Chen, Jose B Cruz, C. Kwan, M. Kruger","doi":"10.1109/AERO.2007.352800","DOIUrl":"https://doi.org/10.1109/AERO.2007.352800","url":null,"abstract":"In an adversarial military environment, it is important to efficiently and promptly predict the enemy's tactical intent from lower level spatial and temporal information. In this paper, we propose a decentralized Markov game (MG) theoretic approach to estimate the belief of each possible enemy course of action (ECOA), which is utilized to model the adversary intents. It has the following advantages: (1) It is decentralized. Each cluster or team makes decisions mostly based on local information. We put more autonomies in each group allowing for more flexibilities; (2) A Markov decision process (MDP) can effectively model the uncertainties in the noisy military environment; (3) It is a game model with three players: red force (enemies), blue force (friendly forces), and white force (neutral objects); (4) Correlated-Q reinforcement learning is integrated. With the consideration that actual value functions are not normally known and they must be estimated, we integrate correlated-Q learning concept in our game approach to dynamically adjust the payoffs function of each player. A simulation software package has been developed to demonstrate the performance of our proposed algorithms. Simulations have verified that our proposed algorithms are scalable, stable, and satisfactory in performance.","PeriodicalId":6295,"journal":{"name":"2007 IEEE Aerospace Conference","volume":"95 1","pages":"1-13"},"PeriodicalIF":0.0,"publicationDate":"2007-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76968184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-03-03DOI: 10.1109/AERO.2007.352872
K. Przytula, A. Choi
This paper describes a general-purpose probabilistic framework for reasoning in diagnosis and prognosis. The framework provides a mathematically rigorous way of handling uncertainty, which is often present in diagnosis and is inherent to prognosis. It is based on an extension of Bayesian network models and Bayesian inference. It coherently integrates multiple sources of evidence in diagnosis and prognosis, including component usage, environmental conditions of operation as well as component health and health trends. The framework has been applied to diagnosis of very complex transportation and aviation systems and to prognosis of electromechanical and electronic subsystems in aviation.
{"title":"Reasoning Framework for Diagnosis and Prognosis","authors":"K. Przytula, A. Choi","doi":"10.1109/AERO.2007.352872","DOIUrl":"https://doi.org/10.1109/AERO.2007.352872","url":null,"abstract":"This paper describes a general-purpose probabilistic framework for reasoning in diagnosis and prognosis. The framework provides a mathematically rigorous way of handling uncertainty, which is often present in diagnosis and is inherent to prognosis. It is based on an extension of Bayesian network models and Bayesian inference. It coherently integrates multiple sources of evidence in diagnosis and prognosis, including component usage, environmental conditions of operation as well as component health and health trends. The framework has been applied to diagnosis of very complex transportation and aviation systems and to prognosis of electromechanical and electronic subsystems in aviation.","PeriodicalId":6295,"journal":{"name":"2007 IEEE Aerospace Conference","volume":"73 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2007-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82192944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-03-03DOI: 10.1109/AERO.2007.352739
E. Urgiles, J. Wilcox, O. Montes, S. Osman, K. Venkateswaran, M. Cepeda, J. Maxim, L. Braby, S. Pillai
The highest degree of Planetary Protection (PP) applies to landed planetary missions and sample return missions. To date, Dry Heat Microbial Reduction (DHMR) treatment is the only NASA approved PP technique for meeting the stringent sterility requirements for life detection missions and to prevent forward contamination. However, spacecraft (s/c) and payloads are made up of a diverse set of man-made materials and components, some of which are incompatible with DHMR. NASA has therefore begun investigating several complementary sterilization techniques to DHMR. Here, we report on our progress in the investigation of the effectiveness of electron beam (e-beam) irradiation technique funded by a NASA Mars Exploration Program (MEP'03) award. E-beam irradiation using deep penetrating (several centimeters) high-energy (10 MeV) electrons is a well-developed method used for sterilization of food products in bulk quantities using linear accelerators. In contrast, low-energy (100 keV) electrons deposit their energy into about 50 micrometers, comparable to the scale of bacterial spores (typically several micrometers). The match between the depth of the penetration and spore size makes the "low-energy" electron irradiation extremely efficient for surface sterilization. E-beam irradiation is non-contact, leaves no residues, and as our preliminary results indicate is compatible with many s/c materials. Secondary contamination is often unavoidable since pre-sterilized s/c parts are used again for functional testing and re-assembly, necessitating reapplication of sterilization treatment. The 100 keV electron source is sufficiently small so that it could be made portable, which would make it suited for treatment localized, previously sterilized parts and subsystems.
{"title":"Electron beam Irradiation for Microbial Reduction on Spacecraft Components","authors":"E. Urgiles, J. Wilcox, O. Montes, S. Osman, K. Venkateswaran, M. Cepeda, J. Maxim, L. Braby, S. Pillai","doi":"10.1109/AERO.2007.352739","DOIUrl":"https://doi.org/10.1109/AERO.2007.352739","url":null,"abstract":"The highest degree of Planetary Protection (PP) applies to landed planetary missions and sample return missions. To date, Dry Heat Microbial Reduction (DHMR) treatment is the only NASA approved PP technique for meeting the stringent sterility requirements for life detection missions and to prevent forward contamination. However, spacecraft (s/c) and payloads are made up of a diverse set of man-made materials and components, some of which are incompatible with DHMR. NASA has therefore begun investigating several complementary sterilization techniques to DHMR. Here, we report on our progress in the investigation of the effectiveness of electron beam (e-beam) irradiation technique funded by a NASA Mars Exploration Program (MEP'03) award. E-beam irradiation using deep penetrating (several centimeters) high-energy (10 MeV) electrons is a well-developed method used for sterilization of food products in bulk quantities using linear accelerators. In contrast, low-energy (100 keV) electrons deposit their energy into about 50 micrometers, comparable to the scale of bacterial spores (typically several micrometers). The match between the depth of the penetration and spore size makes the \"low-energy\" electron irradiation extremely efficient for surface sterilization. E-beam irradiation is non-contact, leaves no residues, and as our preliminary results indicate is compatible with many s/c materials. Secondary contamination is often unavoidable since pre-sterilized s/c parts are used again for functional testing and re-assembly, necessitating reapplication of sterilization treatment. The 100 keV electron source is sufficiently small so that it could be made portable, which would make it suited for treatment localized, previously sterilized parts and subsystems.","PeriodicalId":6295,"journal":{"name":"2007 IEEE Aerospace Conference","volume":"1 1","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2007-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82371595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-03-03DOI: 10.1109/AERO.2007.352751
J. W. Zuckermandel, S. Enger, Neeraj Gupta, Jeff Summers
MicroSat Systems, Inc. (MSI) has developed a low cost, lightweight, solar array system using thin-film photovoltaic (TFPV) material to meet power generation needs for future responsive space missions. The Folded Integrated Thin Film Stiffener (FITS) is the deployment portion of the system. FITS is an integrated, passively deployed solar array structure designed specifically for TFPV, however a variety of photovoltaic (PV) options can be utilized by using the FITS deployment technology. FITS extends the boundaries of space PV systems by eliminating conventional rigid structures and mechanisms to maximize the lightweight and low stowage volume advantages of TFPV. FITS uses multifunctional, foldable components that store energy to provide deployment force and deployed stiffness, and have integrated power cabling to meet the demanding mass, cost and power requirements of programs like the TacSat series and anticipated future responsive space missions. MSI has completed the build and qualification test program for a two wing experimental solar array for the Air Force Research Laboratory (AFRL) TacSat-2 mission scheduled for launch in November of 2006. The array utilizes amorphous silicon (a-Si) thin-film photovoltaics on a 1-mil stainless steel substrate from United Solar Ovonic (USOC), integrated with MSIldquos patented FITS solar array deployment system. The experimental solar array will provide 120 W of additional power to the spacecraft in excess of the primary arrays, while providing valuable on-orbit performance data of the TFPV to the aerospace community for future mission planning. MSI is also under contract with AFRL to design, fabricate, and test a 380 W end of life (EOL) FITS wing focusing on the scalability and modularity of the FITS design.
MicroSat系统公司(MSI)开发了一种使用薄膜光伏(TFPV)材料的低成本、轻质太阳能电池阵列系统，以满足未来响应式空间任务的发电需求。折叠集成薄膜加强器(FITS)是系统的展开部分。FITS是专门为TFPV设计的一种集成的、被动部署的太阳能阵列结构，但是通过使用FITS部署技术可以利用多种光伏(PV)选项。FITS通过消除传统的刚性结构和机制来扩展空间光伏系统的边界，以最大限度地发挥TFPV的轻量化和低积载体积优势。FITS使用多功能、可折叠的组件来存储能量，以提供部署力和部署刚度，并集成了电力电缆，以满足TacSat系列等项目对质量、成本和功率的苛刻要求，以及预期的未来响应性太空任务。MSI公司已经完成了为空军研究实验室(AFRL)计划于2006年11月发射的TacSat-2任务的两翼实验太阳能阵列的建造和资格测试计划。该阵列利用非晶硅(a- si)薄膜光伏电池在1毫米不锈钢衬底上，该衬底来自United Solar Ovonic (USOC)，集成了MSIldquos专利的FITS太阳能阵列部署系统。实验太阳能电池阵列将为航天器提供超过主阵列120瓦的额外功率，同时为未来任务规划提供有价值的TFPV在轨性能数据。MSI还与AFRL签订了设计、制造和测试380 W寿命终止(EOL) FITS机翼的合同，重点是FITS设计的可扩展性和模块化。
{"title":"Modular, Thin Film Solar Arrays for Operationally Responsive Spacecraft","authors":"J. W. Zuckermandel, S. Enger, Neeraj Gupta, Jeff Summers","doi":"10.1109/AERO.2007.352751","DOIUrl":"https://doi.org/10.1109/AERO.2007.352751","url":null,"abstract":"MicroSat Systems, Inc. (MSI) has developed a low cost, lightweight, solar array system using thin-film photovoltaic (TFPV) material to meet power generation needs for future responsive space missions. The Folded Integrated Thin Film Stiffener (FITS) is the deployment portion of the system. FITS is an integrated, passively deployed solar array structure designed specifically for TFPV, however a variety of photovoltaic (PV) options can be utilized by using the FITS deployment technology. FITS extends the boundaries of space PV systems by eliminating conventional rigid structures and mechanisms to maximize the lightweight and low stowage volume advantages of TFPV. FITS uses multifunctional, foldable components that store energy to provide deployment force and deployed stiffness, and have integrated power cabling to meet the demanding mass, cost and power requirements of programs like the TacSat series and anticipated future responsive space missions. MSI has completed the build and qualification test program for a two wing experimental solar array for the Air Force Research Laboratory (AFRL) TacSat-2 mission scheduled for launch in November of 2006. The array utilizes amorphous silicon (a-Si) thin-film photovoltaics on a 1-mil stainless steel substrate from United Solar Ovonic (USOC), integrated with MSIldquos patented FITS solar array deployment system. The experimental solar array will provide 120 W of additional power to the spacecraft in excess of the primary arrays, while providing valuable on-orbit performance data of the TFPV to the aerospace community for future mission planning. MSI is also under contract with AFRL to design, fabricate, and test a 380 W end of life (EOL) FITS wing focusing on the scalability and modularity of the FITS design.","PeriodicalId":6295,"journal":{"name":"2007 IEEE Aerospace Conference","volume":"28 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2007-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81457386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-03-03DOI: 10.1109/AERO.2007.353088
Guoqing Zhou, Wuming Zhang
The paper presents our initial research results on space-ground wireless sensor web with its application in the urban micro-temperature spatial distribution and its relation to population density and land coverage percentage. NASA MODIS onboard the Terra satellite is taken as one note in this web, and the ground segment consists of in situ networked sensor nodes, which in fact are an integration of Mica weather board. All in situ sensor nodes (motes) are networked and communicated through wireless network to collect the micro-temperature and meteorological data. When the MODIS satellite passes by the study area, the networked in situ sensor nodes are informed to turn on for data collection, and then transmit their readings to the base station at ODU through wireless communication. Due to data redundancy in this sensor web, we first developed the algorithm for data mosaic reduction, then interpolate the urban temperature through point data collected by the sensor web and MODIS temperature data, and finally analyzed the relationship between urban temperature and population density and land use percentage.
{"title":"Space-Ground Sensor Web for Study of Urban Micro-Environment","authors":"Guoqing Zhou, Wuming Zhang","doi":"10.1109/AERO.2007.353088","DOIUrl":"https://doi.org/10.1109/AERO.2007.353088","url":null,"abstract":"The paper presents our initial research results on space-ground wireless sensor web with its application in the urban micro-temperature spatial distribution and its relation to population density and land coverage percentage. NASA MODIS onboard the Terra satellite is taken as one note in this web, and the ground segment consists of in situ networked sensor nodes, which in fact are an integration of Mica weather board. All in situ sensor nodes (motes) are networked and communicated through wireless network to collect the micro-temperature and meteorological data. When the MODIS satellite passes by the study area, the networked in situ sensor nodes are informed to turn on for data collection, and then transmit their readings to the base station at ODU through wireless communication. Due to data redundancy in this sensor web, we first developed the algorithm for data mosaic reduction, then interpolate the urban temperature through point data collected by the sensor web and MODIS temperature data, and finally analyzed the relationship between urban temperature and population density and land use percentage.","PeriodicalId":6295,"journal":{"name":"2007 IEEE Aerospace Conference","volume":"19 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2007-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81458263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-03-03DOI: 10.1109/AERO.2007.352666
Guobiao Cai, Dingqiang Zhu, Xiaoying Zhang
Estimation the temperature distribution on nozzle wall by predicting the thermal environment is most important for assessing the life of the nozzle. For that purpose, the coupling simulation of the conjugate heat transfer and transient temperature on the rocket nozzle wall is studied. The equation of radiative heat flux on surfaces of an enclosure filled with inhomogeneous, participating media is established to compute the radiative heat flux, the Bazi equation is used to compute the convective heat transfer at the nozzle wall from the hot gases, the differential equation of 2-D transient conduction in cylindrical coordinate is established and discretized with reclusion form. The conjugate heat transfer coupling with the transiental temperature of two composite walled nozzles are computed, one is the nozzle of an experimental rocket engine fabricated with stainless substrate and a ZrO2 coating, the other is constructed with multi-layer composite materials. The results show that: the temperatures both on the inside and outside faces of the rocket nozzle increase with time after startup of the rocket engine, the former increase rapidly while the latter increase slowly. On the same cross section, the temperature decreases along the radius inside the wall, which is maximal at the outside face while minimal at the inside face. The temperature of the straight and contraction section of nozzle increases as axial coordinate increases and becomes maximal at the throat, while decreases with axial coordinate in diverging section. The coupling simulation method and the computed results are tested reasonable by comparing the computed results with reported results in reference.
{"title":"Coupling Simulation of Heat Transfer and Temperature of the Composite Walled Nozzle of Rocket","authors":"Guobiao Cai, Dingqiang Zhu, Xiaoying Zhang","doi":"10.1109/AERO.2007.352666","DOIUrl":"https://doi.org/10.1109/AERO.2007.352666","url":null,"abstract":"Estimation the temperature distribution on nozzle wall by predicting the thermal environment is most important for assessing the life of the nozzle. For that purpose, the coupling simulation of the conjugate heat transfer and transient temperature on the rocket nozzle wall is studied. The equation of radiative heat flux on surfaces of an enclosure filled with inhomogeneous, participating media is established to compute the radiative heat flux, the Bazi equation is used to compute the convective heat transfer at the nozzle wall from the hot gases, the differential equation of 2-D transient conduction in cylindrical coordinate is established and discretized with reclusion form. The conjugate heat transfer coupling with the transiental temperature of two composite walled nozzles are computed, one is the nozzle of an experimental rocket engine fabricated with stainless substrate and a ZrO2 coating, the other is constructed with multi-layer composite materials. The results show that: the temperatures both on the inside and outside faces of the rocket nozzle increase with time after startup of the rocket engine, the former increase rapidly while the latter increase slowly. On the same cross section, the temperature decreases along the radius inside the wall, which is maximal at the outside face while minimal at the inside face. The temperature of the straight and contraction section of nozzle increases as axial coordinate increases and becomes maximal at the throat, while decreases with axial coordinate in diverging section. The coupling simulation method and the computed results are tested reasonable by comparing the computed results with reported results in reference.","PeriodicalId":6295,"journal":{"name":"2007 IEEE Aerospace Conference","volume":"67 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2007-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78943095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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