Strategies and determinants for successful space technology transfer

The following paper reports the results of a research work carried from 2008 on the topic of strategies and determinants of space technology Transfer (TT). In particular, the aim of this study is to present: 1. The policies and strategies the major space agencies adopt for TT, 2. The operational mechanisms and determinants involved in the transfer of space technologies to other industrial sectors. To this extent we have conducted in the last five years: six case studies of large space agencies, four TT case studies concerning the construction of scientific satellites, two case studies focused on space to earth TT programs undertaken by the Japanese aerospace agency, and two TT case studies examining Italian space companies.The comparative and comprehensive analyses of these studies indicate that the space agencies of the more industrialized countries aim primarily at consolidating and developing the industrial systems in their own countries, which include the use of technology transfer programs, and that the transfer of space technologies follows the route “Earth–Space–Earth”. With regard to the determinants of the TT process, the most important of these correlate with the type of technology in transfer, whereas organizational, economic and financial determinants have less significance.     

基于动量轮转速标定的轨道控制方法研究

某地球同步三轴卫星因故障导致推力器工作效率不稳定,使得采用原有方案进行向西轨道控制时姿态变化大,控制准确度降低.针对上述问题,通过分析卫星用于姿态控制的偏置动量轮的控制规律,利用星体角动量守恒条件,建立了偏置动量轮转速变化与轨道半长轴变化之间的相关性数学模型,提出了一种改进的基于偏置动量轮转速标定的轨道控制方法,同时结合姿态的稳定变化制定了轨道控制实施方案,并将其应用于实际卫星轨道控制中,取得了良好的控制效果.改进的控制方法提高了轨道控制的准确率,使得半长轴误差幅度由最大60％提高到0.2％左右,增加了姿态的稳定性,使得俯仰姿态变化幅度由最大0.7°减小到0.2°左右,降低了控制风险,减轻了地面控制人员的负担.     

壁面导热对微型向心涡轮性能及流动影响

为了探讨传热对于微型向心涡轮的性能和流动的影响规律,根据微型向心涡轮的特点,针对涡轮的轮毂侧壁面传热现象,建立了涡轮的气动性能随传热量变化的一维模型,并利用数值模拟对模型进行了验证,分析了不同传热量下微型向心涡轮的流动变化。结果表明所发展的模型有较好的精确度,可以用以评估传热对微型向心涡轮性能的影响;较大的传热会改变转子进口相对气流角并影响转子整个通道内的流动;涡轮对外传热使得涡轮输出功降低,涡轮效率明显降低。      

任务计划地面站编队数据加载方法研究

随着航空电子系统不断发展,任务计划地面站作为航电系统的一个场站保障设备,为飞行前数据的组织、任务数据加载、飞行后记录数据的管理传输和视频/音频的回放提供了一种快速、准确、规范和安全的技术手段。为适应航空电子系统多机编队任务参数地面加载需求,确保多个任务计划中加载数据的准确性,降低用户对编队内几架甚至十几架飞机制作任务参数的难度,本文提出了合理有效的编队数据加载方案,给用户的使用带来了极大的方便。     

Estimation of the Love and Shida numbers: h2, l2 using SLR data for the low satellites

In this paper we present results for the global elastic parameters: Love number h₂ and Shida number l₂ derived from the analysis of Satellite Laser Ranging (SLR) data. SLR data for the two low satellites STELLA (H = 800 km) and STARLETTE (H = 810 km) observed during 2.5 years from January 3, 2005 until July 1, 2007 with 18 globally distributed ground stations were analyzed. The analysis was done separately for the two satellites. We do a sequential analysis and study the stability and convergence of the estimates as a function of length of the data set used.     

Venus observations from ENVISAT–SCIAMACHY: Measurements and modeling

This work shows the capability of observing Venus with a sensor originally designed for Earth remote sensing. SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY), onboard ENVISAT, successfully observed visible and near-infrared spectra from the Venusian atmosphere. The Venus spectra were simulated using a line-by-line radiative transfer model. The single scattering approximation was applied in order to consider the effects of an approximately 20 km-thick haze layer above the main cloud deck, which was considered as a reflecting cloud located in the upper atmosphere of the planet. CO₂ absorption lines could be distinguished in both observed and simulated spectra and a good agreement between them was also found.     

SerDes器件在遥感相机系统中的应用

基于当前遥感相机谱段数量的不断增加、分辨率的不断提升等方面造成的数据传输问题,分析了目前广泛应用的并行数据传输系统所面临的技术瓶颈,提出采用串行发送/解串(SerDes)方式加以替代的方案,通过对比分析,指出采用该方式传输数据的优点,进而阐述文章所采用的串行发送/解串芯片-TLK2711的工作原理、传输协议等,最终通过试验证明了其在遥感相机系统中应用的可行性,为后续遥感相机研制提供参考。     

基于北斗/GNSS精密时频量值传递综述

介绍了北斗/GNSS精密时间频率量值传递技术及其应用研究进展,通过对北斗共视比对技术的研究,设计出利用北斗共视与国家授时中心GNSS CV精密时间服务系统进行比对,从而实现用户与标准时间UTC的溯源完成基于GNSS CV技术的时间频率计量服务系统设计,创新性地提出提高北斗共视比对技术以及研制多模多频GNSS CV量值传递设备的研究方向。     

倾角对含油工质冷凝换热影响的实验研究

随着航天器热控制的发展,蒸气压缩热泵排热系统等热控方式逐渐受到人们的重视,其中冷凝换热对热泵的性能好坏有重要的影响。为了研究重力场对冷凝换热的影响,将紫铜直管冷凝器置于蒸气压缩热泵系统中,通过改变重力场与流动方向的夹角,测量得到了不同倾角下的冷凝换热系数和压降。实验结果表明,倾角对直管内冷凝换热系数的影响较大,不同倾角下的换热系数差别达30%,远大于不同倾角对直管内蒸发换热的影响;压缩机润滑油对冷凝换热的影响也很大,相比较无润滑油冷凝换热系数低30%以上。随着质量流量的增加,压缩机润滑油的影响逐渐减弱。
     

从月球逃逸探测小行星的发射机会搜索

从月球逃逸探测小行星的发射机会搜索因需考虑日、地、月引力的影响而使问题变得复杂。针对该多体系统的发射机会搜索问题,提出了一种分层渐近的搜索方法。该方法首先通过分析地月系质心与小行星的几何关系,搜索从地月系质心到小行星的发射机会,进而以地月运动为研究对象,推导出了从月球轨道切向逃逸机会的判别条件,并基于此判别条件及等高线图法对逃逸机会进行了搜索。同时,为提高所得发射机会在多体模型下的轨道修正收敛性,给出了基于月心逃逸轨道参数为终端约束的日-地与日-地-月动力学模型的轨道渐近修正方法。最后,以近地小行星(3908)Nyx和(190491)2000 FJ20为例,搜索其从月球逃逸的发射机会,仿真计算表明了该方法的有效性。