System for space materials evaluation in LEO environment

This paper describes the conception and experimental setup of a new concept for a Vacuum Ultraviolet with extreme Thermal Vacuum Cycle system and the evaluation of LEO satellites materials with the equipment. The system was developed in the framework of a study of spacecraft debris generation due to satellites materials degradation, when exposed to space environment. The study was developed in the framework of an ESA project. Its main purpose was to evaluate the characteristics and the quantity of debris resulting from surface of satellites due spacecraft materials degradation and provide input to space debris models. The experimental setup developed partially simulates the space environment, on an accelerated mode, as endured by a spaceship in Low Earth Orbit, allows the testing of materials to a Vacuum, Ultraviolet and thermal cycles. This thermal cycling provided to the sample holder was implemented using an innovative mechanical thermal switching architecture. This architecture allows temperature cycling of +200 ºC to -200 ºC without the use of LN2. The experimental setup design, manufacture and final characterization is presented

Space debris generation in GEO: Space materials testing and evaluation

The aim of this work is to evaluate what happens to the spacecraft materials beyond the spacecraft End of Life. A review of spacecraft external materials and effects of space environment is presented. This paper results from a continued study on spacecraft material degradation, and space debris formation in geostationary orbit (GEO). In this paper a 20-year GEO dose profile that combines simultaneous UV, particles irradiation and thermal cycling was applied to a set of external spacecraft materials. These materials comprised MLI assemblies, Velcros fixation and spacecraft painting. The evaluation of these external spacecraft materials, exposed to simulated space environment have confirmed the criticality of degradation of MLI, Velcros fixation and painting, with delamination mechanisms and particulate contamination. The synergy of space radiation (particles, UV) and thermal cycling ages the material and induces mechanical stress, causing creation of brittle surfaces, cracks and delamination. These phenomena cause serious damage to exposed surfaces, changing the surfaces thermo-optical properties, and may induce the generation of space debris. In particular, experimental results show the delamination of internal MLI layers and the severe degradation of the Velcros

The research of automobile electric control bus technology based on CAN/LIN mixed protocol

传统汽车电气控制系统中采用的点对点通信方式，对于电子化程度越来越高的汽车而言，将使其线束十分复杂，不仅增加了电气系统成本，而且会因为节点繁多使系统运行可靠性降低。总线网络能够大量减少控制线数，提高可靠性，因此，采用总线控制成为汽车电气控制系统技术发展的必然趋势。如何在汽车上建立基于总线技术的汽车电气控制系统问题自然成为汽车电子领域广受关注的研究热点。西门子公司已经利用PLC完成CAN总线控制系统，由于其具有抗干扰性强、线路简化、传输速率高、系统可任意扩展等优点，正受到国内外高度重视，但其成本高，很多国内汽车生产厂家不能接受。在这种情形下，福州源光亚明电器有限公司（沈阳中顺汽车供应商）委托厦门大...The traditional automobile electrical control system used in peer-to-peer communications, the freetly increased electronic level of automobiel makes the wiring harness more complicated by which not only increases costs, but also lower the reliability of system because of the various nodes. Bus network can decrease the number of the control lines and increase the reliability greatly. Therefore, the...学位：工学硕士院系专业：物理与机电工程学院机电工程系_测试计量技术及仪器学号：2005130175

Analyse des circuits integres par microscopie electronique en transmission : controle de qualite, evaluation de la fiabilite

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

SEU rate calculation with GEANT4 (comparison with CREME 86)

This paper reports on single-event upset (SEU) rate calculations using the GEANT4 code. Single event effect rate modeling can be performed using various approaches. In this paper, we propose to compare the standard rectangular parallepiped (RPP) cosmic ray effects in microelectronic code (CREME86) model with our direct Monte Carlo simulation using the GEANT 4 (radiation transport code developed by CERN) software. The results obtained on two device types are in good agreement with CREME86. (14 refs)

Space environmental testing of novel candidate materials for multilayer insulation

International audienceMultilayer insulation forms the outer barrier of a satellite towards space. Polymer foils used in multilayer insulation have to withstand the space environment for mission durations often lasting well above 10 years. This paper outlines the space environmental test campaign performed to qualify novel and advanced polymer foils to reduce blanket mass and replace export-controlled materials. Complete multilayer insulation layups were irradiated; these were composed of thicker outermost layers of the reference material Kapton®, a white polyimide and an alternative, conductive black polyimide and up to seven thin internal, aluminized 6  μm or 3  μm polyethylene terephthalate and polyethylene naphthalate layers separated by nonwoven spacers. One sample set consisted of 25  μm polyether-ether-ketone foil and 6  μm internal vacuum-deposited-aluminum-coated polyether-ether-ketone layers. Materials were exposed to ultraviolet, electrons and protons simulating a 15-year geostationary orbit mission. Absorptance was measured at various stages in situ during the exposures, and emittance was measured ex situ at the beginning and end of the test. With tensile testing, exposure influence on foil mechanical properties was determined and compared with pristine and reference materials. Although the white polyimide was sensitive to ultraviolet and showed strong degradation after ultraviolet and proton exposure, degradation of all other materials was within expected limits and compatible to state-of-the-art foils

Comparison between ground tests and flight data for two static 32 KB memories

International audienceThe Microelectronics and Photonics Testbed (MPTB) carrying twenty-four experiments on-board a scientific satellite is in a high radiation orbit since November 1997. This paper presents SEU flight results on two commercial static RAMs includes in two of the MPTB experiments

Influence des oxydes d'espacement et des LDDs sur la réponse à la dose ionisante pour des MOSFETs fonctionnant à températures cryogéniques

International audienceIn this work, the radiation responses of 0.25 μm bulk transistors irradiated up to 300 krad are discussed. The electricals characteristics shown are measured after irradiation at 95 K, 150 K, and 300 K. The transconductance improves significantly with total ionizing dose (TID) at low temperature and does not vary at room temperature. The impact of incomplete ionization of impurities introduced into the Lightly Doped Drain extensions is examined. Since the transconductance increase is more pronounced for the shortest transistors, positive charges trapped in spacer oxides are likely to constitute the source of this increase. The Technology Computer-Aided Design simulations help us to discuss the influence of charge build-up at the spacers' locations on the drain to source resistance. By the means of a resistivity analysis, the influence of LDD doping level and operating temperature on the TID response of devices is analyzed. Its potential evolution with technological integration is investigated