Missile Electronic System Hardness Assurance Program

A hardness assurance program suitable for a retaliatory or deterrent missile system is discussed. The program consists of three phases: the establishment of suitable controls and screens to ensure piece part hardness, a supplier data monitoring program to measure hardness related parameters in a timely fashion to obtain advanced warning of potential problems, and a hardness assurance verification testing (HAVT) program to periodically measure the radiation response of parts, circuits, subsystems, and systems on a sample basis to ensure proper functioning in simulated radiation environments. All of the data relevant to hardness assurance is stored in computer memory and routinely interrogated with programs which compare current results with the engineering baseline data and other data from preceding lots. Other computer programs enable statistical estimation of system response to the radiation environment with confidence based on the expanding data base provided by the HAVT program.     

Modeling of “gradual” solar energeticparticle events using a stochastic differential equation method

We have modeled “gradual” solar energetic particle events through numerical simulations using a StochasticDifferential Equation (SDE) method. We consider that energetic particle events are roughly divided into two groups: (1) where the shock was driven by coronal mass ejections (CMEs) associated with large solar flares, and (2) where they have no related solar events apart from the CMEs. (The detailed classification of energetic particle events was discussed in our previous paper.) What we call “gradual” solar energetic particle events belong to the former group. Particles with energies greater than 10 MeV are observed within several hours after the occurrence of flares and CMEs in many gradual events. By applying the SDE method coupled with particle splitting to diffusive acceleration, we found that an injection of high energy particles is necessary for early enhancement of such a high-energy proton flux and that it should not be presumed that the solar wind particles act as the seed population.     

中俄联合火星电离层星-星掩星探测

中俄联合火星星-星掩星探测是人类首次在火星空间环境进行此类的联合试验。用于探测火星电离层的星-星掩星技术较以前星地间的探测技术相比,有可接收高信噪比信号,反演精度高,可探测火星上太阳天顶角大于43°,或者小于138°的区域电离层等优点。本文介绍了中俄联合火星星-星掩星探测方案、基本原理,给出了主要技术指标、地面模拟测试结果。     

Space experiments aboard the Lomonosov MSU satellite

At present, the Institute of Nuclear Physics of Moscow State University, in cooperation with other organizations, is preparing space experiments onboard the Lomonosov satellite. The main goal of this mission is to study extreme astrophysical phenomena such as cosmic gamma-ray bursts and ultra-high-energy cosmic rays. These phenomena are associated with the processes occurring in the early universe in very distant astrophysical objects, therefore, they can provide information on the first stages of the evolution of the universe. This paper considers the main characteristics of the scientific equipment aboard the Lomonosov satellite.     

Detonation engine fed by acetylene–oxygen mixture

The advantages of a constant volume combustion cycle as compared to constant pressure combustion in terms of thermodynamic efficiency has focused the search for advanced propulsion on detonation engines. Detonation of acetylene mixed with oxygen in various proportions is studied using mathematical modeling. Simplified kinetics of acetylene burning includes 11 reactions with 9 components. Deflagration to detonation transition (DDT) is obtained in a cylindrical tube with a section of obstacles modeling a Shchelkin spiral; the DDT takes place in this section for a wide range of initial mixture compositions. A modified ka-omega turbulence model is used to simulate flame acceleration in the Shchelkin spiral section of the system. The results of numerical simulations were compared with experiments, which had been performed in the same size detonation chamber and turbulent spiral ring section, and with theoretical data on the Chapman–Jouguet detonation parameters.     

Modeling of the very high velocity impact process with respect to in-situ ionization measurements

This overview deals with very high impact velocities, where complete vaporization of an impacting cosmic dust particle is to be expected upon expansion from the high pressure high temperature state behind the stopping shock (v > 15 km/s). The topics discussed are the mechanics and thermodynamics of compression, adiabatic release, equation of state and nonequilibrium states upon expansion. The case of very high particle porosity (ρ 1 g/cm³) and the case of very small dust masses (m < 10⁻¹⁷ g) are discussed from what one presently knows. The possibility of three body collisions in the expanding gas phase is discussed briefly. The effect of oblique impact is discussed with respect to its relevance to the ionization process. The numbers communicated are up to the highest “experimental” impact velocities (80 km/s, Halley mission). As one goes to lower impact velocities (20 < v < 30 km/s) there is still complete vaporization of the dust particle but ionization out of the bulk of the particle becomes low. Other than thermal processes may become important. Ideas are outlined to understand their physical nature.     

Hardware reconfiguration algorithm in multiprocessor systems of integrated modular avionics

Reconfiguration of multiprocessor systems makes it possible to improve their failure-resistance that is especially important for the integrated modular avionics systems. The algorithm considered in this paper allows minimizing the reservation and providing the better safety level and more effective flight completion or even its further execution in the case of failures of airborne equipment.     

Data Association and Track Management for the Gaussian Mixture Probability Hypothesis Density Filter

The Gaussian mixture probability hypothesis density (GM-PHD) recursion is a closed-form solution to the probability hypothesis density (PHD) recursion, which was proposed for jointly estimating the time-varying number of targets and their states from a sequence of noisy measurement sets in the presence of data association uncertainty, clutter, and miss-detection. However the GM-PHD filter does not provide identities of individual target state estimates, that are needed to construct tracks of individual targets. In this paper, we propose a new multi-target tracker based on the GM-PHD filter, which gives the association amongst state estimates of targets over time and provides track labels. Various issues regarding initiating, propagating and terminating tracks are discussed. Furthermore, we also propose a technique for resolving identities of targets in close proximity, which the PHD filter is unable to do on its own.     

The Motion of Coaxial Bodies of Varying Composition on the Active Leg of Descent

The motion of a spacecraft (SC) with double rotation and variable mass on the active leg of its descent is considered. The SC consists of two coaxial bodies. The coaxial scheme is used for gyroscopic stabilization of the SC longitudinal axis by the method of partial spin-up. The equations of spatial motion of coaxial bodies of varying composition are derived and approximate solutions for the angles of spatial orientation are found. The condition of decreasing amplitude of nutation oscillations is obtained, which allows the estimation of efficiency of the stabilization by partial spin-up. The errors in the magnitude and direction of the vector of braking thrust are also determined.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 3, 2005, pp. 224–232.Original Russian Text Copyright © 2005 by Aslanov, Doroshin, Kruglov.     

高纯α-Fe热压缩动态复原机制的研究

用高纯α-Fe在GLEEBLE-1500热模拟机上率进行了热压缩试验。变形温度分别为550℃,700℃,800℃和900℃,应变速率分别为0.001s~(-1),0.01s~(-1),0.1s~(-1),1s~(-1)和10s~(-1)。对其热压缩过程中的显微结构变化及真应力-真应变曲线进行的研究结果表明,形变温度的增加和应变速率降低有利于动态再结晶的进行;对动态再结晶与Z参数关系的研究结果表明,在一定的Z参数范围内即25<1nZ<37,高纯α-Fe可以发生动态再结晶,并给出动态再结晶图。