惯性信息辅助高动态接收机捕获问题的研究

高动态环境为GPS接收机快速捕获信号带来了困难,通过外部的惯性信息辅助,接收机能预先估算高动态栽体产生的多普勒频移,缩小频率搜索范围,减小捕获时间.本文在GPS信号捕获原理的基础上,介绍了多普勒和码偏移误差对检测概率的影响,给出了惯性信息辅助接收机捕获的方法,着重分析了GPS接收机在冷启动和温启动的情况下有惯性辅助和无惯性辅助的平均捕获时间.结果表明在高动态环境下采用惯性信息辅助GPS接收机捕获的方法可以明显地减少接收机捕获的时间,提高接收机捕获的性能.     

Autogeneration of an Instability of a Plasma Composition Equilibrium in the Plasmaspheric Transition Region during a Postsunset High-Altitude Launch of the Vertikal'-10 Rocket

A cause of the instability of equilibrium of plasma ion composition is discussed and exemplified by the data on a burst of amplitudes of small-scale plasma irregularities in the plasmaspheric transition region during an evening launch of the Vertikal'-10 rocket. This burst is accompanied by a simultaneous decrease in the average plasma density at altitudes of 700–1100 km. Specific features of the observed events are compared to postsunset incoherent scatter radar observations of the ion diffusion flux density. It is demonstrated that the instability is caused by peculiarities of the protonosphere–ionosphere interaction associated with a sharp difference between thermal conditions of the ionospheric and protonospheric air shortly after sunset. The induced nonuniformity of postsunset cooling of the protonospheric–ionospheric plasma causes density irregularities in ion diffusion fluxes and generates local bunches of heavy ions, which are usually only a minor impurity to lighter ions. As a result, conditions are created that are favorable for the nondissipative accumulation of potential energy for the mutual opposition of two or more groups of ions with different masses and for the subsequent release of this energy by a threshold excitation of impurity-driven plasma instabilities.     

锥柱形装药旋转火箭发动机的零维内弹道计算

介绍了锥柱形装药的旋转固体火箭发动机的零维内弹道计算方法.计算结果与旋转试验结果吻合较好,两种结果均表明锥柱形装药呈现较大的加速度场效应.     

Prebiotic significance of extraterrestrial ice photochemistry: detection of hydantoin in organic residues

The delivery of extraterrestrial organic materials to primitive Earth from meteorites or micrometeorites has long been postulated to be one of the origins of the prebiotic molecules involved in the subsequent apparition of life. Here, we report on experiments in which vacuum UV photo-irradiation of interstellar/circumstellar ice analogues containing H(2)O, CH(3)OH, and NH(3) led to the production of several molecules of prebiotic interest. These were recovered at room temperature in the semi-refractory, water-soluble residues after evaporation of the ice. In particular, we detected small quantities of hydantoin (2,4-imidazolidinedione), a species suspected to play an important role in the formation of poly- and oligopeptides. In addition, hydantoin is known to form under extraterrestrial, abiotic conditions, since it has been detected, along with various other derivatives, in the soluble part of organic matter of primitive carbonaceous meteorites. This result, together with other related experiments reported recently, points to the potential importance of the photochemistry of interstellar "dirty" ices in the formation of organics in Solar System materials. Such molecules could then have been delivered to the surface of primitive Earth, as well as other telluric (exo-) planets, to help trigger first prebiotic reactions with the capacity to lead to some form of primitive biomolecular activity.     

Survival of Bacillus pumilus spores for a prolonged period of time in real space conditions

To prevent forward contamination and maintain the scientific integrity of future life-detection missions, it is important to characterize and attempt to eliminate terrestrial microorganisms associated with exploratory spacecraft and landing vehicles. Among the organisms isolated from spacecraft-associated surfaces, spores of Bacillus pumilus SAFR-032 exhibited unusually high resistance to decontamination techniques such as UV radiation and peroxide treatment. Subsequently, B. pumilus SAFR-032 was flown to the International Space Station (ISS) and exposed to a variety of space conditions via the European Technology Exposure Facility (EuTEF). After 18 months of exposure in the EXPOSE facility of the European Space Agency (ESA) on EuTEF under dark space conditions, SAFR-032 spores showed 10-40% survivability, whereas a survival rate of 85-100% was observed when these spores were kept aboard the ISS under dark simulated martian atmospheric conditions. In contrast, when UV (>110?nm) was applied on SAFR-032 spores for the same time period and under the same conditions used in EXPOSE, a ～7-log reduction in viability was observed. A parallel experiment was conducted on Earth with identical samples under simulated space conditions. Spores exposed to ground simulations showed less of a reduction in viability when compared with the "real space" exposed spores (～3-log reduction in viability for "UV-Mars," and ～4-log reduction in viability for "UV-Space"). A comparative proteomics analysis indicated that proteins conferring resistant traits (superoxide dismutase) were present in higher concentration in space-exposed spores when compared to controls. Also, the first-generation cells and spores derived from space-exposed samples exhibited elevated UVC resistance when compared with their ground control counterparts. The data generated are important for calculating the probability and mechanisms of microbial survival in space conditions and assessing microbial contaminants as risks for forward contamination and in situ life detection.     

Evaluation of bleomycin-induced chromosome aberrations under simulated microgravity conditions in human lymphocytes using "FISH" techniques

In the present investigation we report the effects of simulated microgravity conditions (clinostat) on the induction of chromosomal aberrations in human lymphocytes in vitro by (R) Bleomycin. Chromosomal aberrations have been analysed by means of fluorescent in situ hybridisation (FISH) and chromosome-specific composite DNA probes (chromosome painting). The results obtained show that, under simulated microgravity conditions, the levels of both symmetrical and asymmetrical (dicentrics, rings), the number of cells bearing "complex" aberrations and hence the total numbers of aberrations were significantly elevated at any of the dose-levels assayed, compared to the parallel treatments performed as 1g control ("ground"). Furthermore, the ratio symmetrical:asymmetrical translocations was markedly elevated under simulated microgravity conditions, compared to the findings usually observed under "normal" 1g conditions. On these bases, we are much inclined to believe that simulated microgravity, rather than limiting the resealing of DNA double strand breaks (DSB's) induced by genotoxic agents is influencing in terms of enhancement the misrejoining of DSB's which is actually responsible for the fixation of the original lesions to DNA into chromosomal aberrations. In addition, the possible different misrepair processes leading to the formation of symmetrical and asymmetrical translocations might be differentially influenced by microgravity being the symmetrical translocations significantly more represented.     

Synthesis of biomass and utilization of plants wastes in a physical model of biological life-support system

The paper considers problems of biosynthesis of higher plants' biomass and "biological incineration" of plant wastes in a working physical model of biological LSS. The plant wastes are "biologically incinerated" in a special heterotrophic block involving Californian worms, mushrooms and straw. The block processes plant wastes (straw, haulms) to produce soil-like substrate (SLS) on which plants (wheat, radish) are grown. Gas exchange in such a system consists of respiratory gas exchange of SLS and photosynthesis and respiration of plants. Specifics of gas exchange dynamics of high plants--SLS complex has been considered. Relationship between such a gas exchange and PAR irradiance and age of plants has been established. Nitrogen and iron were found to the first to limit plants' growth on SLS when process conditions are deranged. The SLS microflora has been found to have different kinds of ammonifying and denitrifying bacteria which is indicative of intensive transformation of nitrogen-containing compounds. The number of physiological groups of microorganisms in SLS was, on the whole, steady. As a result, organic substances--products of exchange of plants and microorganisms were not accumulated in the medium, but mineralized and assimilated by the biocenosis. Experiments showed that the developed model of a man-made ecosystem realized complete utilization of plant wastes and involved them into the intrasystem turnover.     

小卫星姿控动量轮陶瓷球混合轴承性能分析与试验

小卫星的技术发展对星上姿控系统的主要部件一动量轮的主要技术指标提出了严格的要求。为了满足动量轮对轴承的使用要求，本研究开发了Si3N4陶瓷球混合轴承。基于滚动轴承分析理论和摩擦学知识，对其接触应力、旋滚比、轴向刚度、润滑、额定静载荷等指标进行了优化设计和分析。结果显示：与原全钢轴承比较，优化后混合轴承消除了原全钢轴承存在的控制类型“阶跃”问题，在精度寿命指标上具有明显的优势。摩擦力矩测量结果及分析表明该轴承的功耗指标优于原全钢轴承。力学模拟、温度循环试验后动量轮电机电流升高小于5％，表明该轴承具有良好的抗振动冲击能力和温度适应能力。在动量轮连续二年的运转试验中，电机的功耗始终较小而且稳定，进一步证明陶瓷球混合轴承具有良好的抗粘着磨损能力。     

The Dynamics of a Satellite-Gyrostat with a Single Nonzero Component of the Vector of Gyrostatic Moment

The dynamics of a satellite-gyrostat moving in the central Newtonian force field along a circular orbit is studied. In the particular case when the vector of gyrostatic moment is parallel to one of the satellite’s principal central axes of inertia, all the equilibrium states are determined. For each equilibrium orientation, sufficient conditions of stability are obtained as a result of the analysis of the generalized energy integral, and necessary conditions of stability are determined as a result of analysis of the linearized equations of motion. The evolution of regions of validity for the conditions of stability of equilibrium positions are studied in detail depending on the parameters of the problem. All the bifurcation values of the parameters at which qualitative changes of the regions of stability take place are determined.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 4, 2005, pp. 283–294.Original Russian Text Copyright © 2005 by Sarychev, Mirer, Degtyarev.     

Effects of Constant and Variable Accelerations on Crystals Grown onboard Spacecraft by the Method of Directional Crystallization

The effect of constant and time-dependent accelerations (vibrations) on the melt flow and heat and mass transfer in the process of crystal growth by the method of directional crystallization (Bridgman method) onboard spacecraft is numerically investigated. The mathematical formulation of the problem and the technique to solve it numerically are given. The time-averaged flow arising under the action of vibrations in a nonisothermal fluid is investigated. With the help of a rational choice of dimensionless similitude parameters, a generalized dependence on the intensity of melt flow is obtained for the radial segregation of dopants. This dependence is invariant with respect to the type of motive power and thermal boundary conditions in the region of very small velocities of melt flow (creeping flow), which are characteristic for microgravity conditions. The allowable levels of constant accelerations, as well as the frequency dependences of tolerable vibrations, are obtained for five typical semiconductor materials: Ge(Ga), GaAs(Te), InSb(Te), Si(P), and Si(B). It is shown that the radial segregation of dopant is much more sensitive to microaccelerations than the axial one. In the region of small velocities, the latter is determined by the duration of the transition regime, which depends on certain physical properties of the melt. New problems that resulted from the investigations performed are discussed.     

浅析"模仿-反馈"练习法在体育实践教学过程中的作用

在我国普通高校广泛实行"快乐体育"教育理念形势下,总结当前体育实践教学过程存在的不足,分析"模仿-反馈"练习法的特点及作用.得出,"模仿-反馈"练习法有利于发挥学生学习的自主性、积极性和创造性,对学生课堂主体意识的培养以及"快乐体育"教育理念的实现具有重要的促进作用,同时也有利于教师因材施教提高教学效率.     

The first "space" vegetables have been grown in the "SVET" greenhouse using controlled environmental conditions

The paper describes the "SVET" project--a new generation of space greenhouse with small dimensions. Through the use of a minicomputer, "SVET" is fully capable of automatically operating and controlling environmental systems for higher plant growth. A number of preliminary studies have shown the radish and cabbage to be potentially important crops for CELSS (Closed Environmental Life Support System). The "SVET" space greenhouse was mounted on the "CRYSTAL" technological module docked to the Mir orbital space station on 10 June 1990. Soviet cosmonauts Balandin and Solovyov started the first experiments with the greenhouse on 15 June 1990. Preliminary results of seed cultivation over an initial 54-day period in "SVET" are presented. Morphometrical characteristics of plants brought back to Earth are given. Alteration in plant characteristics, such as growth and developmental changes, or morphological contents were noted. A crop of radish plants was harvested under microgravity conditions. Characteristics of plant environmental control parameters and an estimation of functional properties of control and regulation systems of the "SVET" greenhouse in space flight as received via telemetry data is reported.     

HJ-1A卫星CCD相机入射光谱辐射亮度的分析

文章介绍了HJ - 1A卫星CCD相机的任务需求 ,分析了影响CCD相机入射光谱辐射亮度的主要因素 ,通过“6S”软件得到在不同条件下CCD相机入射光谱辐射亮度 ,并依据CCD相机各波段的观测能力与地物的光谱特点 ,最终确定了CCD相机各波段不同增益对应的最大入射光谱辐射亮度。     

Methodological approach to study of cosmonauts errors and its instrumental support

The methodological approach to the study of cosmonauts errors is discussed in the paper. Within its framework an error is considered in psychophysiological aspect as consequence of cosmonaut "psychophysiological troubles" caused by combined effect of flight extreme conditions on his/her organism. This approach was used for the investigation of interrelation between cosmonauts errors, their psychophysiological state and work-rest schedule peculiarities. It includes procedures of expert analysis of data received in the course of radio and TV sessions with crew, analysis of timelines as well deviations in "crew-spacecraft" system functioning. These data are accumulated, systematized and processed in data base. Realization of the suggested approach does not require specialized onboard equipment and crew members time expenditure. Some results of inflight data analysis are presented to illustrate its potentials.     

Survival of spores of the UV-resistant Bacillus subtilis strain MW01 after exposure to low-earth orbit and simulated martian conditions: data from the space experiment ADAPT on EXPOSE-E

In the space experiment "Molecular adaptation strategies of microorganisms to different space and planetary UV climate conditions" (ADAPT), bacterial endospores of the highly UV-resistant Bacillus subtilis strain MW01 were exposed to low-Earth orbit (LEO) and simulated martian surface conditions for 559 days on board the European Space Agency's exposure facility EXPOSE-E, mounted outside the International Space Station. The survival of B. subtilis MW01 spores from both assays (LEO and simulated martian conditions) was determined by a colony-formation assay after retrieval. It was clearly shown that solar extraterrestrial UV radiation (λ≥110?nm) as well as the martian UV spectrum (λ≥200?nm) was the most deleterious factor applied; in some samples only a few spore survivors were recovered from B. subtilis MW01 spores exposed in monolayers. However, if shielded from solar irradiation, about 8% of MW01 spores survived in LEO conditions, and 100% survived in simulated martian conditions, compared to the laboratory controls. The results demonstrate the effect of shielding against the high inactivation potential of extraterrestrial solar UV radiation, which limits the chances of survival of even the highly UV-resistant strain of B. subtilis MW01 in the harsh environments of outer space and the martian surface.     

Martian polar expeditions: problems and solutions.

The Martian polar ice caps are regions of substantial scientific interest, being the most dynamic regions of Mars. They are volatile sinks and thus closely linked to Martian climatic conditions. Because of their scale and the precedent set by the past history of polar exploration on Earth, it is likely that an age of polar exploration will emerge on the surface of Mars after the establishment of a capable support structure at lower latitudes. Expeditions might be launched either from a lower latitude base camp or from a human-tended polar base. Based on previously presented expeditionary routes to the Martian poles, in this paper a "spiral in-spiral out" unsupported transpolar assault on the Martian north geographical pole is used as a Reference expedition to propose new types of equipment for the human polar exploration of Mars. Martian polar "ball" tents and "hover" modifications to the Nansen sledge for sledging on CO2-containing water ice substrates under low atmospheric pressures are suggested as elements for the success of these endeavours.Other challenges faced by these expeditions are quantitatively and qualitatively addressed.     

Modes of uncontrolled rotational motion of the <Emphasis Type="Italic">Progress M-29M</Emphasis> spacecraft

We have reconstructed the uncontrolled rotational motion of the Progress M-29M transport cargo spacecraft in the single-axis solar orientation mode (the so-called sunward spin) and in the mode of the gravitational orientation of a rotating satellite. The modes were implemented on April 3–7, 2016 as a part of preparation for experiments with the DAKON convection sensor onboard the Progress spacecraft. The reconstruction was performed by integral statistical techniques using the measurements of the spacecraft’s angular velocity and electric current from its solar arrays. The measurement data obtained in a certain time interval have been jointly processed using the least-squares method by integrating the equations of the spacecraft’s motion relative to the center of mass. As a result of processing, the initial conditions of motion and parameters of the mathematical model have been estimated. The motion in the sunward spin mode is the rotation of the spacecraft with an angular velocity of 2.2 deg/s about the normal to the plane of solar arrays; the normal is oriented toward the Sun or forms a small angle with this direction. The duration of the mode is several orbit passes. The reconstruction has been performed over time intervals of up to 1 h. As a result, the actual rotational motion of the spacecraft relative to the Earth–Sun direction was obtained. In the gravitational orientation mode, the spacecraft was rotated about its longitudinal axis with an angular velocity of 0.1–0.2 deg/s; the longitudinal axis executed small oscillated relative to the local vertical. The reconstruction of motion relative to the orbital coordinate system was performed in time intervals of up to 7 h using only the angularvelocity measurements. The measurements of the electric current from solar arrays were used for verification.     

Neutralization of negative electric charge of a satellite by ionospheric plasma ions

The dynamics of the process of neutralization of a satellites negative electric charge by the charge of a layer of positive ions of ionospheric plasma is investigated. The changes in the electric field strength, as well as in the velocity and density of plasma ions, are obtained depending on the initial position of a particle and the distance to the satellites surface. It is found that under the conditions of accepted approximations, as the time grows unlimitedly, the satellites charge tends to zero but does not reach this value. The time during which the satellites electric charge decreases in magnitude as many times as specified is determined. It is shown that the negative charge of a satellite and the charge of a layer of plasma ions can form a structure of a double charged layer type whose lifetime is much longer than the time of its formation.Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 1, 2005, pp. 9–18.Original Russian Text Copyright © 2005 by Fedorov.