地基光学图像中本体-帆板结构航天器姿态估计方法

提出一种利用地基光学图像估计空间目标姿态的方法。针对本体-帆板结构航天器外形结构特点，定义了一种不易遮挡的两轴结构特征，设计了地基光学图像中该特征的提取方法；根据航天器成像过程建立了特征点二三维几何投影方程，实现了航天器三维姿态的解算。利用单站序列图像，可获得航天器姿态变化角速度信息。在轨航天器的试验结果表明，本方法能有效地从地基光学图像估计出航天器姿态。     

Observation of the Moon Shadow in Cosmic Ray Muons

The effect of cosmic ray shadowing by the Moon is observed by recording the single muon component with the Baksan underground scintillation telescope (BUST). A statistically significant (three standard deviations) deficit of muon intensity in the Moon's direction is discovered. A comparison of the experimental results with the simulation of the shadowing effect for the BUST observations is made. An estimate of the angular resolution of the BUST for the single muon component is derived experimentally for the first time. The results and the technique developed are planned to be used for observations of the Sun's shadow.     

空间太阳望远镜热光学环境试验技术

空间太阳望远镜在轨期间,空间环境温度变化会严重影响望远镜成像质量,降低分辨率,因此空间太阳望远镜在模拟空间环境下的热光学试验是其研制过程中的关键技术之一。文章介绍了国外部分空间望远镜的热光学试验及低温光学试验设备,并针对国内空间太阳望远镜的研制和试验研究,提出了一些建设性的意见。     

Stability of dynamic algorithms of determination of quasi-stationary satellite orbits

A method of estimating the stability of the problem of orbit determination under disturbances caused by finite accuracy of calculation and geographical siting of observation stations is proposed.     

Quasi-synchronous orbits and their employment for the approach of a spacecraft to Phobos

The problem of construction of quasi-synchronous orbits which pass through a prescribed point over the surface of Phobos at a prescribed instant of time is considered. The orbits should pass as close as possible to the surface of Phobos at each passage above the planned region of landing.     

Operation of the Spektr-R orientation system

Errors in pointing and sustaining Spektr-R are estimated based on the data of star sensors and an angular velocity vector meter, and the calculated values are compared with the observed values. It has been indicated that the achieved pointing accuracy is significantly better than the required accuracy and is independent of the number of star sensors used for this purpose; finally, the stabilization parameters correspond to the anticipated parameters. The original method for processing adjustment observations of the space radio telescope in the 1.35-cm range used to find a systematic deviation of 2.5′ of the telescope real electric axis from the nominal angular position has been described.     

Modelling of the optical observations of a geosynchronous fragmentation event

A study of the evolution and optical detectability of a fragmentation debris cloud in geosynchronous orbit has been carried out. The 1998 NASA breakup model has been used to generate orbit data for 95 fragments larger than 10 cm size from a 1000 kg satellite. The orbital evolution of these fragments is studied using a precision numerical propagator, employing a high-fidelity force model. Although the fragments rapidly disperse throughout the geostationary arc, they remain localised in right ascension of ascending node and inclination, and are driven along a narrow inertial corridor by luni-solar perturbations. The ESA PROOF software is used to study the detectability of the fragments using a 1- and 0.5-m telescope design. The 1-m telescope can detect 82% of the fragments (down to 13 cm in size) whilst the 0.5-m telescope can detect 39% of the fragments (down to 30 cm size). Due to the large along-track spread of the fragments, a time limit of 1-month post-breakup can be established for a space surveillance system to catalogue the breakup fragments. After this time the angular separation is such that the fragments disperse into the background population, and are no longer distinguishable as originating from a common breakup event.     

空间光学望远镜在轨建造中的结构机构技术

围绕空间光学望远镜在轨建造中的结构机构技术进行分析,重点包括结构机构相关的关键技术基本概念和技术特点,分别对大型望远镜空间结构拓扑构型优化及模块技术、光机结构机构的高精度展开调整及锁合技术、典型光机元件的在轨增材制造技术、机器人辅助自主精密装配及控制技术进行了技术内涵及先进技术途径分析.最后展望了在轨建造中结构机构技术...     

一种2π视场高分辨热等离子体分析仪设计与仿真

针对空间热等离子探测中大通量动态范围、宽视场和高分辨率的需求，以带顶盖球形静电分析器为基础设计了2π视场热等离子体分析仪(Hot plasma analyzer, HPA)，探测性能得到显著提升。通过优化球形剖面视场偏转系统以及粒子光学系统，实现对热等离子体的2π视场高角度分辨率探测，可探测能量范围覆盖50 eV~20 keV，能量分辨率优于10%。利用顶盖电压控制方式实现几何因子在两个量级内连续可调，可以满足对太阳风和磁层热等离子体的全空间高分辨探测需求。     

一种提高MIMO雷达角闪烁抑制性能的方法

针对MIMO雷达体制下角闪烁引起的测角误差问题,提出了一种基于RCS自适应融合加权的抑     

微小卫星多约束姿态机动规划方法

针对微小卫星姿态控制中存在的多重指向约束和角速率约束问题，提出一种基于对数型势函数的多约束姿态机动规划方法。首先针对微小卫星携带的光学传感器需躲避强光天体而天线需指向地面保证对地通信这一约束特性，采用对数型势函数方法保证约束姿态指向满足任务要求;其次，针对姿态角速率限制的问题，引入障碍Lyapunov函数确保姿态角速率始终处于约束范围内。与在线优化方法相比，该方法具有计算量小的显著优势，非常适合星上处理能力有限的微小卫星。此外，考虑外界干扰力矩的影响，引入自适应干扰估计律，增强了控制系统的鲁棒性。最后，通过数学仿真对本文方法进行了校验，仿真结果表明，该方法能够快速实现卫星姿态机动到期望指向，与此同时，在整个姿态机动过程中，均满足多重指向约束和姿态角速率约束 要求 。     

A search for narrow band signals with SERENDIP II: a progress report

Commensal programs for the Search for Extraterrestrial Intelligence (SETI), carried out concurrently with conventional radio astronomical observing programs, can be an attractive and cost-effective means of exploring the large multidimensional search space intrinsic to this effort. Our automated commensal system, SERENDIP II, is a high resolution 131,072 channel spectrometer. It searches for 0.49 Hz signals in sequential 64,700 Hz bands of the IF signal from a radio telescope being used for an astronomical observation. Upon detection of a narrow band signal with power above a preset threshold, the frequency, power, time, and telescope direction are recorded for later study. The system has been tested at the Hat Creek Radio Astronomy Observatory 85 ft telescope and the NASA-JPL Deep Space Station (DSS 14) 64 m telescope. It is currently collecting data at the National Radio Astronomy Observatory 300 ft telescope.     

SIGMA: Projet d'Observatoire spatial a haute resolution angulaire pour les sources de rayons gamma

(SIGMA: Project of a high resolution space observatory for gamma rays sources)—The SIGMA space observatory is designed to obtain images of the sky in the hard X-ray/low energy gamma-ray domain (30–2000 keV range), with an angular accuracy of a few are min, within a field of ～7° × 7°, and a sensitivity for point sources down to a level of a few 10^?6 photons cm^?2s^?1keV^?1 (exposure 24 hr). The instrument is designed using the principle of the coded aperture mask telescope with a position sensitive detector derived from the Anger gamma-camera which is used in nuclear medicine. The pseudo-images of the sky are accumulated on board and transmitted to the ground stations for decoding processing. The gross weight of the instrument is 750 kg and its overall dimensions are 3 m long and 1.2 m in diameter.     

Calculation of quasisynchronous orbits of a spacecraft around Phobos for solving the problem of landing on its surface

The problem of selecting quasi-synchronous orbits of a spacecraft around Phobos is considered. These quasi-synchronous orbits are far (with respect to the Hill’s sphere) quasi-satellite orbits with retrograde rotation in the restricted three body problem. The orbit should pass through a given point at a specified time instant. It should also possess a property of minimum distance from the Phobos surface at every passage above the region of planned landing. The equations of dynamics are represented in the form describing the orbit as a combination of motions in two drifting ellipses, inner and outer ellipses. The center of the outer ellipse is located on the inner ellipse. A formula is derived that relates averaged values of half-axes of the inner and outer ellipses. It is used for construction of the first approximation of numerically designed orbit, which makes it possible to simplify and speed up the computing process. The tables of initial conditions obtained as a result of calculations are presented.     

Families of periodic solutions in three-dimensional restricted three-body problem

Planar orbits of three-dimensional restricted circular three-body problem are considered as a special case of three-dimensional orbits, and the second-order monodromy matrices M (in coordinate z and velocity v _z ) are calculated for them. Semi-trace s of matrix M determines vertical stability of an orbit. If |s| ≤ 1, then transformation of the subspace (z, v _z ) in the neighborhood of solution for the period is reduced to deformation and a rotation through angle φ, cosφ = s. If the angle ? can be rationally expressed through 2π,φ = 2π·p/q, where p and q are integer, then a planar orbit generates the families of three-dimensional periodic solutions that have a period larger by a factor of q (second kind Poincareé periodic solutions). Directions of continuation in the subspace (z, v _z ) are determined by matrix M. If |s| < 1, we have two new families, while only one exists at resonances 1: 1 (s = 1) and 2: 1 (s = ?1). In the course of motion along the family of three-dimensional periodic solutions, a transition is possible from one family of planar solutions to another one, sometimes previously unknown family of planar solutions.     

The PRISMA payload optomechanical design, a high performance instrument for a new hyperspectral mission

PRISMA (PRecursore IperSpettrale della Missione Applicativa) hyperspectral instrument is an advanced hyperspectral sensor including a panchromatic camera at medium resolution. The instrument is the focus of the new Earth observation mission that a consortium of Italian companies has started developing under contract of Italian Space Agency. Key features of the instrument are the very high requirement for signal-to-noise and the high quality of data that have to be provided. To meet these demanding figures the optical system has been based on a high transmittance optical system, including a single mirror telescope and two prism spectrometers based on an innovative concept to minimize number of optical elements, while high performance detectors have been chosen for the photon detection. To provide the required data quality for the entire mission lifetime an accurate calibration unit (radiometric and spectral) will be included in the instrument optomechanical assembly. The thermo-mechanical design of the instrument is based on innovative concepts, considering that the use of prism spectrometers implies a tight control of temperature variations to guarantee the stability of all instrument features once in orbit. The presented paper describes the concepts and design principle of the optomechanical assembly of the instrument, at the present status of development.     

Application of information criteria to control the structurally uncertain navigation system of a reusable spacecraft

The problem of attitude control of a gyro-stabilized platform with the structurally uncertain drift model is solved. The solution is realized in two stages. At the first stage, on the basis of the obtained stochastic model of the reusable spacecraft navigation system, the drift model of gyro-stabilized platform is identified. At the second stage, the control of its spatial orientation is synthesized with regard to the found drift model. The results of numerical simulation are presented in conclusion.     

Multi-structural estimation of an integrated navigation system of a reusable spacecraft

An approach to the synthesis of an integrated navigation system is considered for a reusable space-craft that performs an arbitrary spatial maneuver under the conditions of internal and external disturbances. The offered approach provides for a noise-suppressing solution of the navigation problem, both in a regular mode of spacecraft motion, and during its descent along the unplanned trajectory.     

Some new applications of the generalized problem of two fixed centers

A generalized problem of two fixed centers and its limiting version is considered. New possible applications of this problem are obtained. Using a symmetric version of the problem, the external field of gravitation is approximated. The limiting version approximates the inner field.     

空间光学遥感器光-机-热集成分析方法研究

首先对论文的工程背景空间太阳望远镜进行了介绍;然后介绍了空间光学遥感器光 机 热集成分析的技术路径和技术实现,技术实现主要探讨如何将透镜的折射率温度系数效应和反射镜面的热变形效应数据变成光学分析软件可以接受的数据;最后以光 机 热集成分析为基础,对空间太阳望远镜主镜的热设计方案进行了论证。全文说明了光 机 热集成分析的可实现性以及其对热设计的指导、评价和优化。