Acceleration of solar cosmic rays and the fine spectral structure of type II radio bursts

On the basis of data, obtained by means of the ground-based solar service RSTN (Radio Solar Telescope Network) and the geostationary satellite system GOES, the relationship between the solar cosmic rays (SCR) intensity I _p with the proton energy E _p > 1 MeV and parameters of meter-decameter type II radio bursts in the frequency range of 25–180 MHz is studied. The process of proton acceleration by shock waves was characterized by the frequency drift velocity of radio bursts V _mII and the relative difference between radio emission frequencies at the first two harmonics b. It is shown that the coefficient of correlation between I _p and b increases with E _p growing from 0.40 to 0.70, while a similar coefficient between I _p and V _mII does not exceed 0.30. Indications in favor of the two-stage SCR acceleration model are obtained.     

Sounding rocket experiment of bare electrodynamic tether system

An overview of a sounding rocket, S-520-25th, project on space tether technology experiment is presented. The project is prepared by an international research group consisting of Japanese, European, American, and Australian researchers. The sounding rocket will be assembled by the ISAS/JAXA and will be launched in the summer of 2009. The sounding rocket mission includes two engineering experiments and two scientific experiments. These experiments consist of the deployment of bare electrodynamic tape tether in space, a quick ignition test of hollow cathode system in space, the demonstration of bare electrodynamic tether system in space, and the test of the OML (orbital-motion-limit) current collection theory.     

Current distribution control for parallel connected converters. II

For pt.I, see ibid., vol.28, no.3, p.829-840 (1992). In the central-limit control (CLC), the multiloop controls are employed to regulate the output voltage and track the central weighted current, thus equalizing the output current of each converter module (CM). The current distribution error (CDE) between the output current of each CM is used as a criterion in judging system performance. The prediction and simulation results of this control scheme are illustrated. When incorporated with the maximum current limit, the proposed control method can determine the number of required converters in the active state for each load condition. As a result, the efficiency of a system can be increased significantly. A comparison between the performances of the system under master-slave control (MSC) and CLC is given     

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.     

Measuring satellite antennas with a compact hologram test range

Testing of satellite antennas at high millimeter and submillimeter wavelengths has some specific problems not encountered at lower frequencies. The atmospheric attenuation due to water and oxygen molecule resonances at certain frequency bands can be substantial. Therefore, conventional far-field test methods for electrically large antennas are ruled out by the required far-field distance of kilometers or even tens of kilometers. However, the compact antenna test range (CATR) makes such far-field tests possible within an indoor chamber having a controlled atmosphere. The application and ongoing development of a CATR based on a hologram as the focusing element are outlined     

Switched Ethernet testing for avionics applications

Switched Ethernet is being implemented as an avionics communication architecture. A commercial standard (ARINC-664) and an aircraft vendor-specific implementation known as avionics full duplex switched Ethernet (AFDX) have been developed that defines the topology and use of switched Ethernet in an avionics application. In avionics applications, the movement of data between devices must take place in a deterministic fashion and must be delivered reliably. All aircraft flight hardware must be tested to be sure that it will communicate information properly in the switched Ethernet network. The airframe manufacture must test the integrated network to verify that all flight hardware is communicating properly. Testing and maintenance testing is required to perform data communication level testing of switched Ethernet architectures for avionics applications to insure that all communication is deterministic and reliable. This paper provides an overview of a switched Ethernet avionics network and identifies the testing challenges associated with a switched Ethernet avionics application. A practical implementation performing the required tests is discussed.     

A high-altitude barium radial injection experiment

On 16 March 1980 a rocket launched from Poker Flat, Alaska, carried a new type of high-explosive barium shaped charge to 571 km, where detonation injected a thin disk of barium vapor with high velocity nearly perpendicular to the magnetic field. The purpose of the experiment, named “King Crab,” was to advance knowledge of the instabilities, waves, and optical and magnetic effects produced. The TV images of the injection are spectacular, revealing three major regimes of expanding material which showed early instabilities in the neutral gas. The most unusual effect of the injection is a peculiar rayed barium-ion structure lying in the injection plane and centered on a 5 km “black hole” surrounding the injection point. Preliminary computer simulations show a similar rayed structure development due to an electrostatic instability.     

Biological effects of galactic radiation HZE particles in experiments on the orbital station Salyut 7.

Lettuce (Lactuca sativa) seeds were flown on-board the orbital station Salyut 7 for 66-457 days. It was found that a single heavy charged particle (HZE) hitting a seed only slightly affects the subsequent plant growth. However, morphological anomalies of varying type in primordial leaves and roots were observed that show good correlation with the location of the particle track. The most severe damage detected by light and an electron microscopy were "channels" in dry and soaked seeds. The appearance of "channels" seems to be related to the LET of the incident particle. This finding is of considerable importance for assessment of space flight radiation hazard.