The challenge of the US space station

We are on the verge of a new era of commercial and industrial expansion in space that will have a major impact on America's future and on the future of the world. It is a turning point that will set the US national agenda in space well into the 21st century, and, as such, will have an important impact on space-related activities worldwide. The USA is now gearing up to face the challenges of this new era. James Beggs, NASA Administrator, describes the US space station programme.     

Martian cloud systems: Current knowledge and future observations

In this paper we summarise the current understanding of Martian condensate and dust clouds. The paper is particularly concerned with the spatial, temporal and seasonal characteristics of the clouds. The condensate clouds are composed of water and ice particles and occasionally CO₂ particles. Dust clouds are composed of material from the surface and redistributed over the planet through the weather systems. The apparent lack of annual reproductivity of these dust storms forms a major unresolved problem. We discuss in this paper the types of observations needed in future space missions, in particular the requirements for the NASA Mars Geochemical Climatology Orbiter Mission planned for the end of this decade.     

Stratospheric dust and its relationship to the meteoric influx

A review of measurements sensitive to dust in the stratosphere is presented with special emphasis on the data obtained during the last 10 years. The measurements made by indirect techniques such as light scattering tend to show more stratospheric dust than the measurements obtained by direct sampling techniques, although this interpretation is somewhat complicated by the injection of dust from the Bali eruption in 1963. The discrepancy is interpreted as indicating that the stratospheric dust smaller than a few microns diameter is volital. Recent direct experimental evidence of the author supports this conclusion.The size distribution of stratospheric dust is presented as a composite of the results of several observers. A natural break in the distribution at a size of about 5 diameter is interpreted as indicating that the smaller dust is terrestrial in origin, while the larger dust is meteoric in origin. Other evidence is presented to support this conclusion. A comparison with particle flux measurements at 100 km and higher indicates that the meteoric component of the stratospheric dust is ablation products rather than single particles that have survived entry into the atmosphere. It is also argued that the small particles accounting for the high flux as measured by rocket and satellite microphone techniques are not present in the stratosphere.     

Recent advances in the physiology of whole body immersion

Recent investigations have furnished a complete analysis of the hemodynamic events accompanying whole-body immersion. About 700 ml of blood are translocated into the intrathoracic circulation, and heart volume increases by 180 +/- 62 ml. These changes are followed by an increase in stroke volume and cardiac output of over 30%. At the same time a reflex reduction of total peripheral resistance and venous tone occurs. Renin and aldosterone activity are reduced while the 17-hydroxycorticosteroid is not affected. Treatment of the subject with DOCA attenuates but does not extinguish the excess sodium excretion of immersion. This finding strengthens the arguments in favor of an unknown factor enhancing sodium excretion. Finally, the relative activation of the three factors that serve volume control, the excretory function of the kidney, capillary filtration pressure, and the thirst mechanism, is discussed.     

Experimental investigation of the effects of gravity on thermosolutal convection and compositional homogeneity in bridgman grown,compound semiconductors

Lead-tin-telluride has been grown in a thermally stable mode (solutally unstable) and in a solutally stable (thermally unstable) mode in a Bridgman configuration. Significant differences in the crystal morphology and the compositional homogeneity have been found between the two configurations. In addition, for the solutally stable configuration, evidence has been found that the flow characteristics in the melt change drastically during the course of the run.     

Variations in rigidity spectrum and anisotropy of cosmic rays during sporadic phenomena in the heliosphere in October–November 2003

The variations in the cosmic ray (CR) anisotropy have been studied by the method of spectrographic global survey in the period from October 1 to November 30, 2003. The data of ground-based observations of CR intensity measured by the world network of stations were used. It is shown that at some instants of the period under investigation a bidirectional anisotropy of large amplitude (tens of percent) is observed in the angular distribution of particles. This indicates, first, a carryover of looplike structures of the interplanetary magnetic field (IMF) by coronal mass ejections and, second, a high degree of regularity of the IMF in these structures. The maximum amplitude of the bidirectional anisotropy (for particles with a rigidity of 4 GV) was observed on October 29 and 31 (50% and 30%, respectively) and on November 21–24 (15%). Using the data of ground-based and satellite measurements of the CR intensity in the period under study, we have investigated variations of the rigidity spectrum of protons in the energy range from 15 MeV to tens of GeV. The analysis was carried out in the context of the model of CR modulation by regular electromagnetic fields of the heliosphere. Parameters of the model rigidity spectrum of CRs are determined for every hour of observation. Using their values we have estimated the characteristics of electromagnetic fields of the solar corona and heliosphere that were responsible for powerful sporadic phenomena from the end of October to the beginning of November and after November 20, 2003.Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 645–652.Original Russian Text Copyright © 2004 by Dvornikov, Sdobnov, Yudina.     

The Tanaka-Enome criterion and solar activity in October–November 2003 as observed by the Large Pulkovo Radio Telescope

We present the results of spectral and polarization observations of two large sunspot groups, NOAA 0484 and NOAA 0486 + 0488, which determine high solar activity in October–November 2003. The observations are made with the Large Pulkovo Radio Telescope (LPRT) in the range 2.7–20 cm, the one-dimensional (E-W) resolution of observations being 1–6 arc min, respectively. The main characteristics of the corona radio emission above these active regions are measured, allowing us to follow their dynamics during the entire period of their existence on the solar disk with a period of one day. The analysis of the obtained results is presented from the point of view of the well-known Tanaka-Enome criterion [1–2] (on the basis of this criterion one can predict strong flares from characteristics of radio emission of an active region in quasi-quiet state). Using the activity in October–November 2003 as an example, we demonstrate the capabilities of a new method for estimating the level of solar activity. It was developed on the basis of long-term observations of the Sun by LPRT [3].Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 585–594.Original Russian Text Copyright © 2004 by Borisevich, Ilin, Korzhavin, Peterova, Topchilo, Shpitalnaya.     

Sporadic plasma streams and their sources in the period of extraordinary solar activity from October 26 to November 6, 2003

Based on the results of investigations made by various authors applying different semiempirical models, we have formulated the principles of a complex method that allows one to associate sporadic streams of the solar wind (SW) at the Earths orbit with coronal mass ejections (CMEs), which are their sources on the Sun. This method is applied to an analysis of the events in the interval from October 26 to November 6, 2003. It is shown that, in the period under consideration, which is close to the maximum of solar activity, the majority of CMEs (up to 80% of their total number) turn out to be at the base of a chain of streamers. It is also shown that the component of the interplanetary magnetic field is the main factor of geoeffectiveness for six sporadic SW streams. At the same time, an unusually low value of the index minD_st< -300 nT for two streams with the velocities V_max > 1000 km/s is a consequence of the fact that they are not isolated; i.e., the subsequent stream moves through the medium disturbed by the preceding stream.Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 595–607.Original Russian Text Copyright © 2004 by M. Eselevich, V. Eselevich.     

Geosynchronous magnetopause crossings on October 29–31, 2003

During the period October 29–31, 2003, geosynchronous magnetopause crossings (GMC) have been identified based on the magnetic data of the GOES series spacecraft and plasma data of the LANL series spacecraft. It is shown that most of the time the size of the dayside magnetosphere was highly decreased under the effect of very high pressure associated with high velocities and densities of the solar wind plasma, as well as high negative values of the B_z component of the interplanetary magnetic field (IMF). For tens of hours the subsolar magnetopause was deep inside the geosynchronous orbit. During the main phase and at the maximum of the strong geomagnetic storms that occurred in the period under consideration, the dayside magnetosphere was characterized by a strong dawn-dusk asymmetry, so that its size in the postnoon sector considerably exceeded the size in the pre-noon sector. The geomagnetic disturbances in the morning on October 30 and 31, 2003 were accompanied by global magnetospheric pulsations with periods of 5–10 min and high amplitude (up to 0.8 R_E).Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 574–584.Original Russian Text Copyright © 2004 by Dmitriev, Suvorova.     

A New Approach to Geometry of Range Difference Location

Loran, as an example of a ?hyperbolic? range difference location system, provides hyperbolic lines of position on which the target must lie. It is shown in this paper that lines of position need not be hyperbolic, i.e., an exact straight line of position on the plane or the surface of a sphere (where the solution is a great circle) is derived and computer-generated error maps are given.