Simultaneous investigation of magnetospheric plasma and spacecraft charging

The results of magnetospheric plasma fluxes measurement in geosynchronous orbit are presented. The measurements were done onboard the geosynchronous Russian “Electro” spacecraft (SC) in 1995–1997 years. The diurnal variations of the plasma density and temperature were observed at various levels of geomagnetic activity.     

Scattering function of tropospheric aerosol according to the data of polarimetry of the twilight and night sky background

The paper contains the photometric and polarimetric analysis of the sky background near the zenith during the twilights and the nights of different years and seasons. The period of enhanced tropospheric aerosol content during the summer 2009 is noticed. The aerosol scattering of solar emission is separated from the total twilight sky background, and similar data on lunar emission is taken from the night sky background. The results are compared with the data of relatively clear troposphere of winter 2006. The observational data are used to construct the polarization scattering function of tropospheric aerosol particles during the nighttime.     

RPC-MIP: the Mutual Impedance Probe of the Rosetta Plasma Consortium

The main objective of the Mutual Impedance Probe (MIP), part of the Rosetta Plasma Consortium (RPC), is to measure the electron density and temperature of Comet 67P/Churyumov-Gerasimenko’s coma, in particular inside the contact surface. Furthermore, MIP will determine the bulk velocity of the ionised outflowing atmosphere, define the spectral distribution of natural plasma waves, and monitor dust and gas activities around the nucleus. The MIP instrumentation consists of an electronics board for signal processing in the 7 kHz to 3.5 MHz range and a sensor unit of two receiving and two transmitting electrodes mounted on a 1-m long bar. In addition, the Langmuir probe of the RPC/LAP instrument that is at about 4 m from the MIP sensor can be used as a transmitter (in place of the MIP ones) and MIP as a receiver in order to have access to the density and temperature of plasmas at higher Debye lengths than those for which the MIP is originally designed.     

Power law distribution in statistics of failures in operation of spacecraft onboard equipment

The possibility of using the statistics of recurrence time for extreme events is studied in this paper having in mind the problems of control and prediction of failures in spacecraft operation. The information about failures onboard satellites of various types presented by the US National Geophysical Data Center was analyzed. It was found that the probability density of recurrence intervals followed a power law of the Pareto type with an index equal to 2.3. The obtained result is consistent both with the theory of normal catastrophes and with the principle of self-organization of criticality for metastable active heterogeneous environment. A practical consequence of the obtained result consists in the fact that predictions of these extreme events should not rely on traditional models with the second-order Pearson statistics. To make predictions, the models are necessary that take into account the power law distribution of recurrence intervals for failures on satellites. The failures should be considered in these models as extreme events connected with manifestation of the space environment factors.     

A mathematical model of vibration combustion in a tube with sudden cross-section change

The theoretical study of vibration combustion using a model of the pulsejet engine was carried out. The frequencies and amplitudes of gas vibrations that were calculated by the energy method are well agreed with experimental data.     

Accuracy of angle estimation with monopulse processing using twobeams

Expressions are provided for the accuracy of monopulse angle estimation using two beams. It is shown that, if the signal angle is halfway between the angles of the beams, the Cramer-Rao lower bound (CRLB) for monopulse processing is almost as small as the CRLB obtained if the entire array of sensors is used. The monopulse CRLB is considerably poorer if the angle of the signal is equal to that of one of the two beams. The expressions in this correspondence are for a uniformly weighted linear array of M equally spaced sensors, for which N⩾M beams are formed     

Genetic programming for anti-air missile proximity fuze delay-timealgorithms

This paper describes the application of genetic programming to delay-time algorithms for anti-air missiles equipped with proximity fuzes. Current algorithms for determining the delay-time before the detonation of a missile warhead rely on human effort and experience and are, in general, deficient. We show that by applying genetic programming, an evolutionary optimization technique, determination of the timing can be automated and made near-optimal. A simulation study is discussed     

Main characteristics of biological components of developing life support system observed during the experiments aboard orbital complex MIR.

Since 1990, the orbital complex MIR has witnessed several incubator experiments for determination of spaceflight effects on embryogenesis of Japanese quail. First viable chicks who had completed the whole embryological cycle in MIR microgravity hatched out in 1990; it became clear that newborns would not be able to adapt to microgravity unaided. There were 8 successful incubations of chicks in the period from 1990 to 1999. In 1995-1997 the MIR-NASA space science program united Russian and US investigators. As a result, experiments Greenhouse-1 and 2 were performed with an effort to grow super dwarf wheat from seed to seed, and experiment Greenhouse-3 aimed at receiving two successive generations of Brassica rapa. But results of these experiments could not be used for definitive conclusions concerning effects of spaceflight on plant ontogenesis and, therefore, experiments Greenhouse-4 and 5 were staged within the framework of the Russian national space program. The experiments finally yielded wheat seeds. Some of the seeds was left on the space station and, being planted, gave viable seedlings which, in their turn, produced the second crop of space seeds.     

Sunspot Structure and Dynamics

Sunspots are the most prominent magnetic features on the Sun but it is only within the last few years that the intricate structure of their magnetic fields has been resolved. In the penumbra the fields in bright and dark filaments differ in inclination by 30°. The field in the bright filaments is less inclined to the vertical, while the field in dark filaments becomes almost horizontal at the edge of the spot. Recent models suggest that this interlocking-comb structure is maintained through downward pumping of magnetic flux by small-scale granular convection, and that filamentation originates as a convective instability. Within the bright filaments convection patterns travel radially owing to the inclination of the field. A proper understanding of these processes requires new observations, from space and from the ground, coupled with large-scale numerical modelling.     

Prevention of Power Failures in Major Networks

An outline of the philosophy underlying the Federal Power Commission's study of the reliability of electric power systems and their distribution networks is presented. A broad review of bulk power system reliability is given. The steps required for the prevention of major power outages of wide extent and substantial duration are set forth.