HZE-dosimetry on MIR92, IML-1 and D-2

Nuclear track detectors were used to measure the integral Linear Energy Transfer (LET) spectra above 1 GeV per cm water behind the complex material shielding inside a spacecraft. The measurements are compared with predictions of the contribution of high charge, high energy HZE particles of the galactic cosmic radiation taking into account the influence of solar and geomagnetic modulation and shielding by matter.     

Zonal mean temperature, pressure, zonal wind and geopotential height as functions of latitude

The new zonal mean COSPAR International Reference Atmosphere (CIRA-86) of temperature, zonal wind, and geopotential/geometric height is presented. This data can be used as a function of altitude or pressure and has nearly pole-to-pole coverage (80°S-80°N) extending from the ground to approximately 120 km. Data sources and methods of computation are described; in general, hydrostatic and thermal wind balance are maintained at all levels and latitudes. As shown by a series of cross sectional plots, the new CIRA accurately reproduces most of the characteristic features of the atmosphere such as the equatorial wind and the general structure of the tropopause, stratopause, and mesopause.     

Distribution of calmodulin in corn seedlings: Immunocytochemical localization in coleoptiles and root apices

Immunofluorescence techniques have been used to study the distribution of calmodulin in several tissues in etiolated corn ( , var. Bear Hybrid) seedlings. Uniform staining was seen in the background cytoplasm of most cell types. Cell walls and vacuoles were not stained. In coleoptile mesophyll cells the nucleoplasm of most nuclei was stained as was the stroma of most amyloplasts. The lumen border of mature tracheary elements in coleoptiles also stained. In the rootcap the most intensely stained regions were the cytoplasms of columella cells and of the outermost cells enmeshed in the layer of secreted slime. Nuclei in the rootcap cells did not stain distinctly, but those in all cell types of the root meristem did. Also in the root meristem, the cytoplasm of metaxylem elements stained brightly. These results are compared and contrasted with previous data on the localization of calmodulin in pea root apices and epicotyls and discussed in relation to current hypotheses on mechanisms of gravitropism.     

Modeling of “gradual” solar energeticparticle events using a stochastic differential equation method

We have modeled “gradual” solar energetic particle events through numerical simulations using a StochasticDifferential Equation (SDE) method. We consider that energetic particle events are roughly divided into two groups: (1) where the shock was driven by coronal mass ejections (CMEs) associated with large solar flares, and (2) where they have no related solar events apart from the CMEs. (The detailed classification of energetic particle events was discussed in our previous paper.) What we call “gradual” solar energetic particle events belong to the former group. Particles with energies greater than 10 MeV are observed within several hours after the occurrence of flares and CMEs in many gradual events. By applying the SDE method coupled with particle splitting to diffusive acceleration, we found that an injection of high energy particles is necessary for early enhancement of such a high-energy proton flux and that it should not be presumed that the solar wind particles act as the seed population.     

Measurements of bidirectional reflectance of ordinary chondrite for muses-C in-situ detection

MUSES-C, a Japanese sample return mission, is targeting a small near Earth asteroid, 1998SF36, which is considered an S-type asteroid and is similar in spectroscopy to LL class ordinary chondrite meteorite ([Binzel et al., 2001]). Although this mission will bring us detailed photometric data, that is, disk-resolved bidirectional reflectance data of the asteroid, there were few bidirectional reflectance data of ordinary chondrite meteorites. For the purpose of comparison with the data obtained by the in-situ observation, we have performed measurements of bidirectional reflectance of ordinary chondrite samples.

Here we summarize the result of our laboratory measurements of the bidirectional reflectance and compare them with the scattering property of 1998SF36. Although the geometric albedo of 1998SF36 is higher than the typical value of S-type asteroids, however, the laboratory data of ordinary chondrite are similar to or brighter than the model disk-resolved reflectance of 1998SF36 derived from disk-integrated ground-based data. We found in our laboratory data that there is a positive correlation between the surface roughness and the strength of the opposition effect. A stronger opposition effect in the reflectance of 1998SF36 than the laboratory data may therefore indicate that the surface of the asteroid has rougher structure than our laboratory samples.     

Solar physics and interferometry mission (SPI)

This paper presents the scientific objectives of the Solar Physics and Interferometry Mission (SPI), describes succinctly the model payload and summarizes mission's issues. Novel instrumentation (interferometry) and clever mission design (small platform on low orbit with high telemetry and dedicated smaller platform on hexapod for permanently Sun-centered instruments) allow both spectral imaging and Helioseismology at very high spatial and temporal resolutions. Although not retained by ESA, this mission could become reality through NASA MIDEX and/or CNES PROTEUS opportunities as soon as 2007–2008.     

Metabolic changes in rats subjected to space flight for 18.5 days in the biosatellite Cosmos 936

From an investigation of the activity of six glucocorticoid dependent liver enzymes, the existence of chronic, transient, stress-induced hypercorticosteronaemia during flight is probable. This hypercorticosteronaemia arises from weightlessness and induces gluconeogenesis. Weightlessness also caused substantial increases in liver glycogen level. The increased lipolytic activity and that of lipoprotein lipase in several groups of animals could be interpreted as enhancement of fat mobilization and utilization under the influence of stress. As this latter enhancement was also found in ground-based controls, it may have been due to the stress of handling rather than to space flight per se.     

Survival in extreme dryness and DNA-single-strand breaks.

A wide variety of organisms (the so-called "anhydrobiotes') is able to survive long periods of time in a state of utmost dehydration and can thus survive in extremely dry environments including artificially imposed or space vacuum. Known strategies of survival include the accumulation of certain polyols, especially disaccharides, which help prevent damage to membranes and proteins. Here we report that DNA in vacuum-dried spores is damaged to a very substantial degree by processes leading to DNA strand breaks. Most of these lesions are obviously repaired during germination, but extensive damage to DNA and enzymes after long exposure times (months to years) finally diminish the chances of survival.     

Biosphere 2 Test Module: a ground-based sunlight-driven prototype of a closed ecological life support system.

Constructed in 1986, the Biosphere 2 Test Module has been used since the end of that year for closed ecological systems experiments. It is the largest closed ecological facility ever built, with a sealed variable volume of some 480 cubic meters. It is built with a skin of steel spaceframes with double-laminated glass panels admitting about 65 percent Photosynthetically Active Radiation (PAR). The floor is of welded steel and there is an underground atmospheric connection via an air duct to a variable volume chamber ("lung") permitting expansion and contraction of the Test Module's air volume caused by changes in temperature and barometric pressure, which causes a slight positive pressure from inside the closed system to the outside thereby insuring that the very small leakage rate is outward. Several series of closed ecological system investigations have been carried out in this facility. One series of experiments investigated the dynamics of higher plants and associated soils with the atmosphere under varying light and temperature conditions. Another series of experiments included one human in the closed system for three, five and twenty-one days. During these experiments the Test Module had subsystems which completely recycled its water and atmosphere; all the human dietary needs were produced within the facility, and all wastes were recycled using a marsh plant/microbe system. Other experiments have examined the capability of individual component systems used, such as the soil bed reactors, to eliminate experimentally introduced trace gases. Analytic systems developed for these experiments include continuous monitors of eleven atmospheric gases in addition to the complete gas chromatography mass spectrometry (GCMS) examinations of potable, waste system and irrigation water quality.     

Chemistry of the interstellar medium--an evolutionary dead end?

An analysis of the experimental data available and of the present theoretical concepts shows that even the initial physicochemical chemical precellular stages of biological evolution are impossible in the interstellar medium, while biomonomers possibly formed on asteroids and comets might have participated after transportation to the Earth in the final stages of the origin of the first precellular biological structures and then in the first living cells.