空间环境和污染对光学器件的影响

用于观测卫星、气象卫星、空间望远镜上的各种光学器件及其光学涂层必须经受住空间环境和污染的考验才能保证航天器的可靠性。采取有效措施减少空间环境的影响是解决问题的关键。对于低温光学仪器是个相对独立的系统,在冷却期间必须保证仪器中最冷的传感器芯片保持最高温度,这样在冷却之前污染物就不会被吸附在表面上。最好的方法是在光学器件的适当位置安装加热器及污染控制罩。     

Passive coolers for pre-cooling of JT loops for deep space infrared imaging applications

Infrared instruments (IR) for deep space imaging missions, such as the James Webb Space Telescope (JWST) and Planck, require cryogenic cooling for proper operation of their focal plane arrays (FPA) in far infrared and sub-millimeter wavelength ranges. The FPA is sometimes located meters away from the spacecraft. To meet such remote cooling requirement, a Joule-Thomson (J-T) loop becomes a convenient choice for either direct cooling for the FPA or for serving as a heat sink for a cascade cooling system. The refrigerant lines of the JT loop inevitably suffer parasitic heat leak primarily due to IR backload as they traverse from the spacecraft to the FPA. An actively cooled JT loop using a mechanical pre-cooler located at the spacecraft will experience the highest parasitic heat leak since the lines are cold through the entire length whereas a passively cooled JT loop can utilize a number of radiators to cool the lines down gradually in stages and hence reduce the heat leak. In addition to savings in power and mass, a passive cooler offers consistent and predictable performance with practically no performance degradation in a thermally stable orbit, such as one around the Sun-Earth L2 point. Passive coolers are less popular in low temperature applications when their cooling capacity diminishes rapidly in proportion to T4 until the temperature reaches a point where either the parasitic heat leak becomes so significant or its size becomes so excessive that the passive cooling scheme becomes impractical. Despite the limited capacity, passive cooling may still prove to be a viable alternative to active cooling depending on the operating temperature and heat dissipation rate of the FPA. The current effort aims at evaluating the merit of using passive coolers as an alternative to using a mechanical cooler for pre-cooling of a JT loop for remote IR instrument cooling. A parametric study is conducted to explore the merits of passive cooling of a JT loop in a temperature range below 30 K. Correlations between cooling capacity, heat leak from supporting structure, and the operating temperature are investigated to provide design guidelines. Radiator staging options will also be presented and discussed.     

Design and test of an electronic nose for monitoring the air quality in the international space station

Long-term manned space missions requires a continuous monitoring of the air quality inside the spacecraft. For this scope, among several different solutions, electronic noses have been considered. On behalf of European Space Agency an electronic nose specifically designed for air quality control in closed environment is under development. After several ground experiments concerning the monitoring of a biofilter efficiency, the instrument has been tested during the ENEIDE mission on board of the International Space Station. in this paper the instrument main concepts and its performance in ground and space experiments are illustrated.     

Accelerator test of an angle detecting inclined sensor (ADIS) prototype with beams of Ca and fragments

The measurement of cosmic rays and Solar energetic particles in space is basic to our understanding of the Galaxy, the Sun, phenomena in the Heliosphere and what has come to be known broadly as “space weather”. For these reasons, cosmic ray instruments are common on both scientific spacecraft and operational spacecraft such as weather satellites.

The resource constraints on spacecraft generally mean that instruments that measure cosmic rays and Solar energetic particles must have low mass (a few kg) and low power (a few W), be robust and reliable yet still highly capable. Such instruments must identify ionic species (at least by element, preferably by isotope) from protons through the iron group. The charge and mass resolution of heavy ion instruments in space depends upon determining ions’ angles of incidence. The Angle Detecting Inclined Sensor (ADIS) system is a highly innovative and uniquely simple detector configuration used to determine the angle of incidence of heavy ions in space instruments. ADIS replaces complex position sensing detectors (PSDs) with a system of simple, reliable and robust Si detectors inclined at an angle to the instrument axis.

In August 2004, we tested ADIS prototypes with a ⁴⁸Ca beam at the National Superconducting Cyclotron Laboratory's (NSCL) Coupled Cyclotron Facility (CCF). Among the analyses performed on the data taken at the NSCL, we demonstrate that our prototype design with an ADIS system has a charge resolution of less than 0.25e. We also present a more generalized analytic derivation of instrument response and report on the corresponding analysis of Monte-Carlo modeling data.     

多体动力学热-结构耦合圆管单元及其应用

航天器柔性附件在突加太阳辐射热载荷作用下的热诱发振动会严重影响航天器的正常工作。航天器是典型的多体系统;部件间的相互作用会严重影响航天器的热诱发振动响应,因而有必要使用多体系统动力学的方法对此进行研究。该文在柔性多体系统动力学框架内,推导建立了一种考虑辐射换热的热-结构耦合圆管单元。温度变化会使圆管单元产生轴向伸缩和横向弯曲;同时,在给定辐射热流作用下,圆管单元受热条件与其姿态和变形相关。使用该圆管单元、刚体单元和柔性体单元可以实现多体系统动力学热-结构耦合分析。该文的方法首先用于哈勃太空望远镜太阳能电池板简化模型的热诱发振动分析,所得结果与文献结果吻合良好。然后,该文研究了由本体、动量轮、柔性支撑杆和端部质量组成的航天器在突加辐射热流作用下的振动响应。结果表明：各部件间的相互作用会对航天器的热诱发振动响应产生显著影响。     

Moderate resolution imaging spectrometer-tilt (modis-t)

The Moderate Resolution Imaging Spectrometer-Tilt (MODIS-T) instrument is being constructed for flight on the Earth Observing System (EOS). It is an imaging spectrometer utilizing a grating-type, reflecting Schmidt optical design that must provide a 1.1-km spatial resolution at nadir from a spacecraft altitude of 705 km with a 1500-km cross-track swath and a ±50° fore and aft tilt capability. The instrument is required to cover the wavelength range from 400 to 880 nm in approximately 15-nm steps with less than 2.3% instrument-induced polarization. The absolute radiometric accuracy must be at least 5% over the full dynamic range of the instrument.     

载人航天器中橡胶密封结构低温性能研究

载人航天器对密封性能要求极为严苛,密封结构的泄漏特性与温度相关。本文研究了一种典型的硅橡胶密封结构的泄漏方式,通过对低温下橡胶材料的透气性能的测试,结果表明：从50℃下降到5℃时、气体通过材料的渗透量降低约一个数量级。本文还通过实测材料在低温下的应力-应变关系、低温下材料的收缩特性,借助ABAQUS分析软件建立了该结构的压缩状态的有限元模型,得到了低温下密封应力变化情况,并据此计算了界面泄漏结果：低温下,密封结构的界面泄漏量略有所增大。本文研究的某典型橡胶密封结构在低温下的气体渗透泄漏和界面泄漏的量化数据,为产品在低温下的使用可靠性评估打下基础,也为类似结构设计提供参考。     

Optimized reflective wide-angle Michelson phase-stepping interferometer

A fully achromatic wide-angle interferometer that uses cat's-eye retroreflectors has been developed for optical Doppler imaging in the ultraviolet region. Here the solar flux is much weaker than in the visible, so the solar background control system ordinarily used in spacecraft optical instruments becomes unnecessary, which results in a much smaller instrument and a broader viewing geometry. The theory and the test results associated with the development of this instrument are described. Minimizing the aberrations involved in cat's-eye geometry resulted in optimum cat's-eye and interferometer designs. The results of tests conducted in the visible and the near-UV regions demonstrated experimentally that the field of view of the interferometer is 5 degrees and that the residual wave distortions are approximately 1/8 wave with visibilities sufficient for high-resolution Doppler imaging.     

Outgassing and the choice of materials for space instrumentation

Instruments built for scientific observations from spacecraft and sounding rockets, having endured the rigours of the rocket launch, have to perform in a vacuum environment between 10^?3 and 10^?15 torr. The internal pressures within compartments of an instrument may be higher, depending on venting ports and the outgassing rates of materials. These pressures are calculable and some typical figures are given. If pump-out is slow, there are risks of electrical breakdown of high voltage systems, although the lives of ‘open window’ detector devices, and of bearings in mechanisms, may be extended. Optics, and heat exchanger elements, have been contaminated by volatile condensibles. Authorities supporting space science and technology have adopted the VCM test for the screening and selection of materials without seriously limiting the scope of instrument designers.     

基于热刺激电流的空间电介质载流子迁移率测量方法

为了研究空间用聚酰亚胺材料在不同温度下的载流子迁移率,提出了基于热刺激电流(TSC)测量载流子迁移率的模型。对试样施加一段时间的电压,会有电荷注入到材料中。当试样温度降低到液氮温度时,注入电荷被保持在材料的陷阱中。假设入陷的电荷服从玻尔兹曼分布,陷阱中电荷会随着材料温度的上升而出陷,然后在自建电场的作用下向电极传输。在这个物理模型的基础上,推导出了载流子迁移率的解析公式。通过计算,得到了聚酰亚胺在不同温度下的载流子迁移率。同时,采用空间电荷限制电流方法测量了聚酰亚胺材料的迁移率。通过比较2种方法得到的迁移率表明,提出的迁移率计算模型可以比较精确地得到在强场下较大温度范围内的载流子迁移率。该方法为空间介质电荷输运规律和机理的研究提供了基础。     

Structural vibrations induced by HVI – Application to the Gaïa spacecraft

Given the growing stability needed for spacecraft in operation to ensure functioning of future instruments whose sensitivity requires an important technological step, perturbations encounter in orbital conditions that used to be negligible, become today an issue. This is the case of micrometeorite impacts whose energy could induce modal response of the flexible structure and imply a dynamic response of the spacecraft which could probably be disturbing for the instrument functioning. The impact environment that could be encountered by the spacecraft is preliminary studied before the definition of test to recreate the excitation with light-gas gun. Experiments are made on samples of structure representative of the ongoing Gaïa astrometric mission project. Response of the structure is recorded to be correlated to finite elements model of the sample. The excitation is then extrapolated to orbital conditions and to Gaïa finite elements model. The final perturbation is compared to the specification. The main conclusion is that for daily impact event, dynamic response of the structure will not disturb Gaïa functioning. Nevertheless, for a yearly impact event, the astrometric mission will largely be disturbed by the dynamic response of the structure to the impact.     

航天器包装箱振动测试系统

充分利用虚拟仪器在振动测试领域的优势,结合三维加速度传感器研发出航天器包装箱振动测试系统,缩短了开发周期,节约了测试成本,实现了长时间实时数据采集并存储,即时显示加速度波形,并根据信号处理的基本原理,对数据进行频谱分析、关键点高亮显示、极值检索、有效值分析、减振效果分析;对采集后的数据加速数据流回放,生成极值、有效值、减振效果报表、打印等功能。     

Compact high-resolution spaceborne echelle grating spectrometer with acousto-optical tunable filter based order sorting for the infrared domain from 2.2 to 4.3 microm

A new compact spaceborne high-resolution spectrometer developed for the European Space Agency's Venus Express spacecraft is described. It operates in the IR wavelength range of 2.2 to 4.3 microm and measures absorption spectra of minor constituents in the Venusian atmosphere. It uses a novel echelle grating with a groove density of 4 lines/mm in a Littrow configuration in combination with an IR acousto-optic tunable filter for order sorting and an actively cooled HgCdTe focal plane array of 256 by 320 pixels. It is designed to obtain an instrument line profile of 0.2 cm(-1). First results on optical and spectral properties are reported.     

Space environment testing of a heat pipe

An experimental heat pipe for spacecraft temperature control systems has been tested in a space environment. The results of the test are described.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 31, No. 6, pp. 990–995, December, 1976.     

A Spacecraft Model Flying Around a Levitated Globe Using?YBCO Bulk Superconductors

A small spacecraft model flying around a levitated globe has been designed based on magnetic force. The globe can be levitated in mid-air by the interaction between the magnets fixed at the North and South poles and the YBCO bulk superconductors installed on the globe frame near each of the poles. The magnetic track for the spacecraft is located at the equatorial circumference. When the small spacecraft with YBCO bulks is being cooled to LN₂ temperature at a certain distance apart from the track, then the spacecraft can be automatically suspended in mid-air near the track and moved along the track without any obvious friction after a push by a hand. The model can be used as a demonstration of magnetic levitation, suspension, side suspending, magnetic bearing, flywheel energy storage, flying spacecraft principle, and can also be used as an educational experiment for the diamagnetic effect and applications of superconducting materials to students.     

基于用户偏好的体温测量仪造型设计

目的 研究体温测量仪造型特征与用户感性意象之间的映射关系,设计出符合用户偏好的体温测量仪。方法 以魅力工学理论为研究基础,运用评价构造法对目标用户进行访谈,整合收集的访谈资料,提炼出8项体温测量仪造型魅力因素,以及其包含的25项具体魅力形态特征,进一步运用数量化Ⅰ类理论,分析用户感性意象与体温测量仪魅力形态特征之间的映射关系,从而明确各个具体魅力形态特征对用户感性意象的影响程度,为设计出符合用户偏好的体温测量仪造型提供设计参考。结论 以实验研究结果为设计依据,完成体温测量仪的造型设计,通过对比实验对设计结果进行验证分析。结果表明,设计出的体温测量仪造型能很好地满足用户偏好,同时,可根据用户对体温测量仪的不同感知意象的偏好,有针对性地识别出相应的魅力形态特征,从而设计出满足用户偏好的体温测量仪。     

深空电推进阻滞势分析仪探测方法研究

随着人类对外太空环境认识的不断深入,电推进已成为通向未知空间领域的重要技术途径。空间电推进对航天器防护结构、能源系统、敏感有效载荷系统均产生不同影响。介绍了基于阻滞势分析仪的电推进等离子体参数探测方法,通过阻滞势分析仪研制和相应的地面模拟实验,计算得到了推力器40cm处的粒子能量、离子密度和离子温度等参数,相关研究为我国电推进航天器的深空应用和发展提供技术参考。     

超高温陶瓷改性C/SiC复合材料的研究进展

超高温复合材料的制备技术是制约新一代航天器发展的一项重要技术,为此近年来国内外积极研制耐超高温、抗烧蚀甚至零烧蚀的复合材料。概述了应用于航天领域的高温热结构复合材料C/SiC和超高温陶瓷材料的研究进展,综述了超高温陶瓷改性C/SiC复合材料的改性机理及制备方法,最后提出了今后研究的重点。     

Planetary cameras

The “first look” phase of planetary imaging has been completed, with many spectacular discoveries made by a wide variety of cameras and spacecraft. Now that planetary scientists have a better idea about what is out there, new cameras can be developed to address specific questions in greater depth. Ideally, these cameras would be fully optimized to carry out their scientific objectives. In reality, however, the numerous constraints and severe environments of a planetary spacecraft often influence the camera design as strongly as the science. New developments in optics, detectors, microcomputers, and structural materials have greatly expanded the capabilities that can be built into a small, lightweight, low-power instrument, and further progress is expected in the coming decade. The new camera designs will be used on a variety of flyby, orbiter, lander, and rover missions now in preparation by NASA and other space agencies throughout the world.     

The use of the Termoizmeritel tm-12 precision multichannel temperature measuring instrument to check resistance thermometers

The main aspects of the use of the Termoizmeritel TM-12 precision multichannel temperature measuring instrument for checking resistance thermometers in accordance with the State Standard GOST R 8.624 are considered. The extended uncertainties of the results of measurements are calculated, and demonstrate the possibility of using the temperature measuring instrument to check resistance thermometers of all grades of accuracy, as specified in the State Standard GOST R 8.625. The advantages of this instrument when used as the basis of a checking laboratory are pointed out.