Trapped proton fluxes measured on board LEO satellites in comparison with models

The proton fluxes from the low-Earth orbital satellites databases (NPOES-17 and CORONAS-F) were analyzed for the quiet geomagnetic period in April 2005. The satisfactory consent was found between the experimental and the AP8 model fluxes of the trapped protons with energy more than ∼10 MeV. At the same time, trapped proton fluxes with energy less than 10 MeV measured by LEO satellites were higher than the ones predicted by the AP8 model in the region of the SAA (drift shell L < 1.5).     

The concept of selecting the main parameters of a lightweight airplane with regard to the requirements of the contemporary Russian market

The basic principles of selecting some design parameters of a lightweight airplane for the contemporary Russian market are presented. Recommendations for selecting these parameters with the service requirements specified are given based on the study performed.     

The Effect of Interfering Signals on the Performance of Angle of Arrival Estimates

The performance of angle of arrival estimates using an array in the presence of interfering signals is evaluated using the Cramer-Rao bound. To do this, a model for interference is developed which presents the interference as narrowband, temporally white, but spatially correlated, noise. The bound is evaluated and it is shown to depend upon the ambiguity function of the array and spatial correlation matrix of the noise plus interference. Motivation of the model in the context of air traffic control and sonar surveillance is presented.     

Estimation of Correlation Functions by Stochastic Approximation

Two techniques for estimating the correlation function of a stationary random process using the method of stochastic approximation are developed. Both provide updated estimates as successive T-second observations are processed. Both assume a functional form for the correlation function that depends on a number of parameters that are estimated. One technique is based on the mean-square error; the other maximizes a likelihood function. Examples are included.     

Biologically weighted measurement of UV radiation in space and on Earth with the biofilm technique.

Biological dosimetry has provided experimental proof of the high sensitivity of the biologically effective UVB doses to changes in atmospheric ozone and has thereby confirmed the predictions from model calculations. The biological UV dosimeter 'biofilm' whose sensitivity is based on dried spores of B. subtilis as UV target weights the incident UV radiation according to its DNA damaging potential. Biofilm dosimetry was applicated in space experiments as well as in use in remote areas on Earth. Examples are long-term UV measurements in Antarctica, measurements of diurnal UV profiles parallel in time at different locations in Europe, continuous UV measurements in the frame of the German UV measurement network and personal UV dosimetry. In space biofilms were used to determine the biological efficiency of the extraterrestrial solar UV, to simulate the effects of decreasing ozone concentrations and to determine the interaction of UVB and vitamin D production of cosmonauts in the MIR station.     

A Pulsewidth-Modulated Dc-to-Dc Converter That Utilizes a Small Number of Components

In general, circuit reliability can be enhanced by either incorporating redundancy or by minimizing a circuits component count. Conventional nonregulating converters generally require two active devices, whereas in regulating converters or switching regulators as many as 10 transistors, either integrated or discrete, is not uncommon. A regulating dc-to-dc converter which provides useful regulation and which can be constructed with either two or three transistors is described.     

Determination of parameters of rotational motion of the <Emphasis Type="Italic">Monitor-E</Emphasis> spacecraft from the telemetry data on solar batteries’ current

The Monitor-E spacecraft executed uncontrolled flight due to emergency situation, no telemetry information on parameters of the spacecraft’s attitude motion being available. So, the problem arose to determine the spacecraft’s rotational motion from the accessible indirect information—the electric current provided by solar batteries. In this paper the integrated statistical technique is described, that allows one to solve this problem. The values of current, obtained over the time interval some tens of minutes long, have been processed simultaneously by the least squares method using the integration of the equations of spacecraft’s rotational motion. As a result of processing, the initial conditions of motion were estimated, and the spacecraft’s moments of inertia were updated, as well as the angles, specifying solar batteries position in the spacecraft-fixed coordinate system. The results of processing of 12 data sets are presented, which allowed us to reconstruct the actual rotational motion of the spacecraft.     

Harnessing functional food strategies for the health challenges of space travel—Fermented soy for astronaut nutrition

Astronauts face numerous health challenges during long-duration space missions, including diminished immunity, bone loss and increased risk of radiation-induced carcinogenesis. Changes in the intestinal flora of astronauts may contribute to these problems. Soy-based fermented food products could provide a nutritional strategy to help alleviate these challenges by incorporating beneficial lactic acid bacteria, while reaping the benefits of soy isoflavones. We carried out strain selection for the development of soy ferments, selecting strains of lactic acid bacteria showing the most effective growth and fermentation ability in soy milk (Streptococcus thermophilus ST5, Bifidobacterium longum R0175 and Lactobacillus helveticus R0052). Immunomodulatory bioactivity of selected ferments was assessed using an in vitro challenge system with human intestinal epithelial and macrophage cell lines, and selected ferments show the ability to down-regulate production of the pro-inflammatory cytokine interleukin-8 following challenge with tumour necrosis factor-alpha. The impact of fermentation on vitamin B1 and B6 levels and on isoflavone biotransformation to agluconic forms was also assessed, with strain variation-dependent biotransformation ability detected. Overall this suggests that probiotic bacteria can be successfully utilized to develop soy-based fermented products targeted against health problems associated with long-term space travel.