Early commercial demonstration of space solar power using ultra-lightweight arrays

Space solar power shows great promise for future energy sources worldwide. Most central power stations operate with power capacity of 1000 MW or greater. Due to launch size limitations and specific power of current, rigid solar arrays, the largest solar arrays that have flown in space are around 50 kW. Thin-film arrays offer the promise of much higher specific power and deployment of array sizes up to several MW with current launch vehicles. An approach to early commercial applications for space solar power to distribute power to charge hand-held, mobile battery systems by wireless power transmission (WPT) from thin-film solar arrays in quasi-stationary orbits will be presented. Four key elements to this prototype will be discussed: (1) Space and near-space testing of prototype wireless power transmission by laser and microwave components including WPT space to space and WPT space to near-space HAA transmission demonstrations; (2) distributed power source for recharging hand-held batteries by wireless power transmission from MW space solar power systems; (3) use of quasi-geostationary satellites to generate electricity and distribute it to targeted areas; and (4) architecture and technology for ultra-lightweight thin-film solar arrays with specific energy exceeding 1 kW/kg. This approach would yield flight demonstration of space solar power and wireless power transmission of 1.2 MW. This prototype system will be described, and a roadmap will be presented that will lead to still higher power levels.     

寄生振荡电路对液体轨姿控发动机电磁阀门阻值测试影响研究

当液体轨姿控发动机所处的测试环境、电磁环境比较复杂,供配电线路干扰较大时．多功能测试仪测试发动机回路阻值结果可能会偏离实际值,出现测试值整体失真现象,主要原因是多功能测试仪对电感性负载测试过程中,存在寄生振荡电路的影响。通过试验验证．在测试电路中增加消振电容,能够有效地消除寄生振荡,解决回路阻值测试整体失真问题。     

Biogenicity of morphologically diverse carbonaceous microstructures from the ca. 3400 Ma Strelley pool formation, in the Pilbara Craton, Western Australia

Morphologically diverse structures that may constitute organic microfossils are reported from three remote and widely separated localities assigned to the ca. 3400?Ma Strelley Pool Formation in the Pilbara Craton, Western Australia. These localities include the Panorama, Warralong, and Goldsworthy greenstone belts. From the Panorama greenstone belt, large (> 40?μm) lenticular to spindle-like structures, spheroidal structures, and mat-forming thread-like structures are found. Similar assemblages of carbonaceous structures have been identified from the Warralong and Goldsworthy greenstone belts, though these assemblages lack the thread-like structures but contain film-like structures. All structures are syngenetic with their host sedimentary black chert, which is associated with stromatolites and evaporites. The host chert is considered to have been deposited in a shallow water environment. Rigorous assessment of biogenicity (considering composition, size range, abundance, taphonomic features, and spatial distributions) suggests that cluster-forming small (<15 μm) spheroids, lenticular to spindle-like structures, and film-like structures with small spheroids are probable microfossils. Thread-like structures are more likely fossilized fibrils of biofilm, rather than microfossils. The biogenicity of solitary large (>15?μm) spheroids and simple film-like structures is less certain. Although further investigations are required to confirm the biogenicity of carbonaceous structures from the Strelley Pool Formation, this study presents evidence for the existence of morphologically complex and large microfossils at 3400?Ma in the Pilbara Craton, which can be correlated to the contemporaneous, possible microfossils reported from South Africa. Although there is still much to be learned, they should provide us with new insights into the early evolution of life and shallow water ecosystems.     

Clathrate hydrates of oxidants in the ice shell of Europa

Europa's icy surface is radiolytically modified by high-energy electrons and ions, and photolytically modified by solar ultraviolet photons. Observations from the Galileo Near Infrared Mapping Spectrometer, ground-based telescopes, the International Ultraviolet Explorer, and the Hubble Space Telescope, along with laboratory experiment results, indicate that the production of oxidants, such as H2O2, O2, CO2, and SO2, is a consequence of the surface radiolytic chemistry. Once created, some of the products may be entrained deeper into the ice shell through impact gardening or other resurfacing processes. The temperature and pressure environments of regions within the europan hydrosphere are expected to permit the formation of mixed clathrate compounds. The formation of carbon dioxide and sulfur dioxide clathrates has been examined in some detail. Here we add to this analysis by considering oxidants produced radiolytically on the surface of Europa. Our results indicate that the bulk ice shell could have a approximately 1.7-7.6% by number contamination of oxidants resulting from radiolysis at the surface. Oxidant-hosting clathrates would consequently make up approximately 12-53% of the ice shell by number relative to ice, if oxidants were entrained throughout. We examine, in brief, the consequences of such contamination on bulk ice shell thickness and find that clathrate formation could lead to substantially thinner ice shells on Europa than otherwise expected. Finally, we propose that double occupancy of clathrate cages by O2 molecules could serve as an explanation for the observation of condensed-phase O2 on Europa. Clathrate-sealed, gas-filled bubbles in the near surface ice could also provide an effective trapping mechanism, though they cannot explain the 5771 A (O2)2 absorption.     

Letting thoughts take wing

Recent developments in neuroelectronics are applied to aviation and airplane flight control instruments. Electromyographic control has been applied to flight simulations using the autopilot interface in order to use gestures to give bank and pitch commands to the autopilot. In other demonstrations, direct rate control was used to perform repeated successful landings and the damage-adaptive capability of inner-loop neural and propulsion-based controls was utilized.     

Improvements in Advanced Electronic Navigation Systems

Advanced electronic navigation systems will be required for future merchant ship operations involving minimum crew manning. These systems will rely on some form of electronic chart, which will require continual and timely updating with the latest correction information. This paper describes a newly developed chart correction computer system capable of automatically updating electronic charts via satellite data transfers. The system can provide a direct computer data link between a shipboard computer and the Defense Mapping Agency's Automated Notice to Mariners System.     

Thermal comfort assessment in civil aircraft cabins

Aircraft passengers are more and demanding in terms of thermal comfort. But it is not yet easy for aircraft crew to control the environment control system(ECS) that satisfies the thermal comfort for most passengers due to a number of causes. This paper adopts a corrected predicted mean vote(PMV) model and an adaptive model to assess the thermal comfort conditions for 31 investigated flights and draws the conclusion that there does exist an uncomfortable thermal phenomenon in civil aircraft cabins, especially in some short-haul continental flights. It is necessary to develop an easy way to predict the thermal sensation of passengers and to direct the crew to control ECS. Due to the assessment consistency of the corrected PMV model and the adaptive model, the adaptive model of thermal neutrality temperature can be used as a method to predict the cabin optimal operative temperature. Because only the mean outdoor effective temperature ET* of a departure city is an input variable for the adaptive model, this method can be easily understood and implemented by the crew and can satisfy 80–90% of the thermal acceptability levels of passengers.     

基于地面实验的蒙皮换热器高空换热性能分析

面向未来我国大功率机载电子设备冷却需求,需要发展新型机载冷却方式,减少对传统环控制冷系统的依赖,为此研究了一种气/气蒙皮换热器用于电子设备热管理.该蒙皮换热器是一种无能耗被动换热方式,在不增加飞机代偿损失的情况下实现大功率电子设备热管理.为了考核所设计的蒙皮换热器机载飞机环境换热性能,设计加工了实验样件,在地面开展了换热性能实验研究工作,获得热边流动传热准则和对流换热系数.在此基础上推演出高空巡航状态下的蒙皮换热器换热性能,获得传热最不利安装位置和改进位置时的传热性能.研究工作预期为未来我国基于蒙皮换热器的飞机综合热管理提供设计及机载应用技术支持.     

基于聚偏二氟乙烯(PVDF)压电薄膜的密封舱壁穿孔损伤识别技术

日益恶化的空间碎片环境将严重威胁空间站及航天员的在轨安全。文章基于聚偏二氟乙烯（polyvinylidene fluoride,PVDF）压电薄膜设计了一种密封舱壁穿孔损伤识别技术方案,用于识别空间碎片超高速撞击对航天器密封舱壁造成的损伤模式,可为航天员合理选择应急措施提供依据。首先,发射超高速弹丸穿透铝合金靶板以模拟密封舱壁被击穿损伤的情况,形成的碎片云撞击PVDF压电薄膜探头,利用信号采集设备获取高速撞击引起的去极化效应信号,识别该信号的频率特征;其次,对PVDF压电薄膜探头及其支撑结构进行敲击试验,模拟在轨运行时因碰撞产生的干扰信号,掌握此类干扰信号的频率特征。试验结果表明,当系统采样频率为20 MHz时：1）所获得的探头去极化效应信号具有极为陡峭的上升沿,且上升沿的时长为亚μs量级;2）去极化效应信号主要由1 MHz以下的信号组成,但也包含少量的3～10 MHz高频成分;3）敲击探头及其支撑结构所产生的干扰信号频率在20 kHz以下。可根据频率差异进行两种信号的识别。