Source and loss processes in the magnetotail

Space Science Reviews -     

Characterization of Cosmic Materials in the Laboratory

One of the main objectives of modern astrophysics is the characterisation of properties and evolution of materials present in space. Production, processing and analysis of cosmic dust analogues in the laboratory represents a powerful tool to interpret astronomical observations and to contribute to the solution of puzzling problems which are so far unsolved. In the present paper we summarize recent results obtained in our laboratory on carbon-based and silicate materials able to simulate various types of cosmic grains. The laboratory data are applied to discuss the nature of spectral features observed in the interstellar medium and in comets. This revised version was published online in June 2006 with corrections to the Cover Date.     

UVCS/SOHO Observations of H I Lyman Alpha Line Profiles in Coronal Holes at Heliocentric Heights Above 3.0 R⊙

The Ultraviolet Coronagraph Spectrometer (UVCS) on the Solar and Heliospheric Observatory (SOHO) has been used to measure spectral line profiles for H I Lyα in the south polar coronal hole at projected heliocentric heights from 3.5 to 6.0 R_⊙ during 1998 January 5–11. Observations from 1.5 to 2.5 R_⊙ were made for comparison. The H I Lyα profile is the only one observable with UVCS above 3.5 R_⊙ in coronal holes. Within this region the outflowing coronal plasma becomes nearly collisionless and the ionization balance is believed to become frozen. In this paper, the 1/e half widths of the coronal velocity distributions are provided for the observed heights. The velocity distributions include all motions contributing to the velocities along the line of sight (LOS). The observations have been corrected for instrumental effects and interplanetary H I Lyα. The half widths were found to increase with projected heliographic height from 1.5 to 2.5 R_⊙ and decrease with height from 3.5 to 5 R_⊙. This revised version was published online in June 2006 with corrections to the Cover Date.     

RF band high resolution sounding of building structures and works

A subsurface radar using a multi-frequency signal has been developed. It is designated for surveying building structures and works. The characteristic feature of this device is the possibility of obtaining sounding plane radio images featuring a high resolution attaining 1…2 cm. The main applications of this device includes the survey of building structures to reveal their heterogeneities and defects and the investigation of premises to detect bugging devices     

Radiation environment at the end of active functioning of <Emphasis Type=Italic>Vernov</Emphasis> satellite

Factors of radiation environment in near-Earth space in a period from December 1 to 10, 2014 have been analyzed, which could affect serviceability of the onboard systems of Vernov spacecraft.     

Dynamics of debye-scale nonstationary plasma structures in the region of auroral field-aligned currents

We consider the formation of small-scale nonstationary plasma structures in the region of relatively strong field-aligned electric currents. The formation of these structures has been shown to be associated with the density instability developed when the current velocity exceeds a critical value. The conditions for the development of this instability can be most favorable in the region of low-density plasma. Numerical calculations have been performed for the initial nonlinear stage of the structure development. The main parameters of the structure, i.e., the times of its formation and destruction, spatial scales, and electric field, have been estimated. The features of the structures are consistent with the existing data from space experiments in the region of auroral field-aligned currents of the Earth.     

New results for the space radiation environment of MIR space station obtained by Liulin dosimeter-radiometer. Comparison with LET spectrometer NAUSICAA

Since 1988 high sensitivity semiconductor dosimeter-radiometer “Liulin” worked on board of MIR space station. Device measured the absorbed dose rate and the flux of penetrating particles. The analysis of the data hows the following new results:

In October 1989 and after March 24, 1991, two additional stable maximums in flux channel were observed in the southern-eastern part of South Atlantic Anomaly (SAA). These two maximums existed at least several months and seem to be due to trapped high energy electron and proton fluxes. In April 1991 additional maximums were localized in the following geographical coordinates regions: LATITUDE = (−35 °)–(−50 °) LONGITUDE = 332 ° − 16 ° and lat.(−46 °)–(−52 °) long. 360 ° − 60 °. Additional maximums diffusion occurs inside radiation belt. Appearance of these maximums seems to be closely connected with preceding powerful solar proton events and associated geomagnetic dynamics of new belt disturbances. After the series of solar proton events in June 1991 we observed significant enhancement of this new radiation belt formation. To achieve sufficient accuracy of dose rate predictions in low Earth orbits the structure and dynamics of new belt should be carefully analyzed to be included in a new environment model.

From the inter comparison of the data from “Liulin” and French developed tissue equivalent LET spectrometer NAUSICAA in the time period August–November 1992 we come to the following conclusions: Mainly there is good agreement between both data sets for absorbed dose in the region of SAA; Different situation of the instruments on the station can explain the cases when differences up to 2 times are observed; At high latitudes usually the tissue equivalent absorbed dose observations are 2 times larger than “Liulin” doses.     

Energy utilization rates during shuttle extravehicular activities

The work rates or energy utilization rates during EVA are major factors in sizing of life support systems. These rates also provide a measure of ease of EVA and its cost in crew fatigue. From the first Shuttle EVA on the STS-6 mission in 1983, we have conducted 59 man-EVA and 341 man-hours of EVA. Energy utilization rates have been measured on each of these EVA. Metabolic rate was measured during each EVA using oxygen utilization corrected for suit leakage. From 1981–1987, these data were available for average data over the EVA or over large segments of the EVA. Since 1987, EVA oxygen utilization data were available at 2-minute intervals. The average metabolic rate on Shuttle EVA (194 kcal/hr.) has been significantly lower than metabolic rates during Apollo and Skylab missions. Peak rates have been below design levels, infrequent, and of short duration. The data suggest that the energy cost of tasks may be inversely related to the degree of training for the task. The data provide insight on the safety margins provided by life support designs and on the energy cost of Station construction EVA.     

Role of the astronaut in operating the Advanced Fluid Physics Module

The role of man in space is investigated in the operation of the Advanced Fluid Physics Module (AFPM), a scientific instrument dedicated to fluid physics research in a microgravity environment and flown on the Spacelab D2 mission. The astronaut involvement is addressed by applying the criteria of the THURIS study, conducted by NASA for the optimization of future manned space flights. Outcomes of the THURIS study are first summarized. The AFPM characteristics and interfaces are briefly presented. The five experiments performed on board Spacelab D2 are introduced and the involvement of the astronaut is described. Finally, THURIS criteria are applied to an AFPM experiment scenario. Results show that, of all the activities involved in the AFPM nominal operation, two thirds are related to hardware manipulation and to procedure following, while the last third uses the unique astronaut intellectual capabilities, making his presence in orbit mandatory for successful experiment completion.