Remote upgrading of a space-borne instrument

The main purposes of experiment “Obstanovka” (“Environment” in Russian) consisting of several instruments are to measure a set of electromagnetic and plasma phenomena characterizing the space weather conditions, and to evaluate how such a big and highly energy consuming body as the International Space Station disturbs the surrounding plasma, and how the station itself is charged due to the operation of so many instruments, solar batteries, life supporting devices, etc. Two identical Langmuir electrostatic probes are included in the experiment “Obstanovka”. In this paper the Langmuir probes for “Obstanovka” experiment are described, including the choice of geometry (spherical or cylindrical), a more reliable method for the sweep voltage generation, an adaptive algorithm for the probe’s operation. Special attention is paid to the possibility for remote upgrading of the instrument from the ground using the standard communication channels.     

PHITS simulations of the Protective curtain experiment onboard the Service module of ISS: Comparison with absorbed doses measured with TLDs

“Protective curtain” was the physical experiment onboard the International Space Station (ISS) aimed on radiation measurement of the dose – reducing effect of the additional shielding made of hygienic water-soaked wipes and towels placed on the wall in the crew cabin of the Service module Zvezda. The measurements were performed with 12 detector packages composed of thermoluminescent detectors (TLDs) and plastic nuclear track detectors (PNTDs) placed at the Protective curtain, so that they created pairs of shielded and unshielded detectors.     

Are small-scale field-aligned currents and magnetosheath-like particle precipitation signatures of the same low-altitude cusp?

We examined some 75 observations from the low-altitude Earth orbiting DMSP, Ørsted and CHAMP satellites which were taken in the region of the nominal cusp. Our objective was to determine whether the actually observed cusp locations as inferred from magnetosheath-like particle precipitation (“particle cusp”) and intense small-scale magnetic field variations (“current cusp”), respectively, were identical and were consistent with the statistically expected latitude of the cusp derived from a huge number of charged particle spectrograms (“statistical cusp”).     

Energetic neutral atom (ENA) and charged particle periodicities in Saturn’s magnetosphere

The Magnetospheric Imaging Instrument (MIMI) on the Cassini spacecraft has observed energetic neutral atoms (ENA) and charged particles at Saturn from mid-2004 to the present. The particles often but not always reveal striking periodic behavior that seems to depend on the type of particle and spacecraft location. When subjected to a Lomb periodogram analysis, energetic electrons (>150 keV) exhibited strong frequency peaks near 10.80 h (the nominal or “base” period of Saturn kilometric radiation) during 2006–2008, but essentially no periodicity during 2005. The electron periodograms also show pronounced “double” frequency peaks in 2007 and 2008. Energetic protons (3–26 keV) show strong peaks near the same period for 2005–2007, but none for 2008. Oxygen ions at the same energies display strong peaks for 2005 and 2006, but not for 2007 and 2008. By projecting the ENA images onto Saturn’s equatorial plane or onto a plane perpendicular to the equatorial plane and then summing the data in the appropriate dimension, “strip” images can be constructed from which a time history can be derived. These time histories of ENA emissions are also subjected to a Lomb periodogram analyses. The energetic hydrogen neutrals (20–50 keV) exhibited periodic behavior only during 2007, while energetic oxygen neutrals (64–144 keV) displayed a strong SKR-like period in 2005 and 2006 but not for 2007 or 2008. Some of this behavior may be due to changing spacecraft aspect relative to the ENA emissions, and some of it may be real. This periodic behavior may be consistent with a rotating anomaly that “flashes” brightly in the midnight-to-dawn sector once per 10.8 h, with the flash parameters depending on particle species and energy.     

Verification of shielding effect by the water-filled materials for space radiation in the International Space Station using passive dosimeters

The dose reduction effects for space radiation by installation of water shielding material (“protective curtain”) of a stack board consisting of the hygienic wipes and towels have been experimentally evaluated in the International Space Station by using passive dosimeters. The averaged water thickness of the protective curtain was 6.3 g/cm². The passive dosimeters consisted of a combination of thermoluminescent detectors (TLDs) and plastic nuclear track detectors (PNTDs). Totally 12 passive dosimeter packages were installed in the Russian Service Module during late 2010. Half of the packages were located at the protective curtain surface and the other half were at the crew cabin wall behind or aside the protective curtain. The mean absorbed dose and dose equivalent rates are measured to be 327 μGy/day and 821 μSv/day for the unprotected packages and 224 μGy/day and 575 μSv/day for the protected packages, respectively. The observed dose reduction rate with protective curtain was found to be 37 ± 7% in dose equivalent, which was consistent with the calculation in the spherical water phantom by PHITS. The contributions due to low and high LET particles were found to be comparable in observed dose reduction rate. The protective curtain would be effective shielding material for not only trapped particles (several 10 MeV) but also for low energy galactic cosmic rays (several 100 MeV/n). The properly utilized protective curtain will effectively reduce the radiation dose for crew living in space station and prolong long-term mission in the future.     

Spiral eddies in the Baltic,Black and Caspian seas as seen by satellite radar data

Despite spiral eddies were first seen on the sea surface more than 40 years ago, there is still a lot of uncertainty concerning these eddies. The present paper is aimed to provide the comprehensive results on the occurrence and statistics of small-scale eddies in the three inner seas (the Baltic, Black and Caspian) using satellite synthetic aperture radar (SAR) images. The dataset used includes over 2000 medium resolution Envisat ASAR and ERS-2 SAR images obtained in 2009–2010 in the different parts of the seas mentioned. As a result of the analysis performed ∼14,000 vortical structures were detected. 71% of them were visualized due to surfactant films (“black” eddies), while 29% due to wave/current interactions (“white” eddies). Practically all the eddies detected were cyclonically rotating. Their diameter was within 1–20 km. Characteristic size of the “black” eddies in all the basins was discovered to be less than that of the “white” eddies. Characteristic eddy size for the Baltic, Black and Caspian seas proved to be strictly proportional to the values of the baroclinic Rossby radius of deformation typical for these basins. The “black” eddies did not demonstrate a significant connection with the basin- and meso-scale surface circulation of the seas. Most of the “white” eddies detected were attributed to the zones with the most intense drift currents, i.e. those along the western boundaries and (in the Baltic Sea only) in the elongated parts of the basin.     

Calculation of the barometric coefficients at the start of the 24th solar activity cycle for particle detectors of Aragats Space Environmental Center

After the major modernization of the data acquisition electronics of the particle detectors operated at Aragats Space Environmental Center (ASEC) calculations of the barometric coefficients of all the monitors were performed in the beginning of the 24th solar activity cycle. The barometric coefficients of particle detectors located at altitudes of 1000 m, 2000 m and 3200 m a.s.l. measuring various secondary cosmic ray fluxes were compared with theoretical expectations and monitors operated on different longitudes and latitudes. The barometric coefficients were also calculated for the several neutron monitors of recently established Eurasian database (NMDB) and SEVAN particle detector networks. The latitude and altitude dependencies of the barometric coefficients were investigated, as well as the dependence of coefficients on energy of the primary particles.     

December 2006 solar extreme events and their influence on the near-Earth space environment: “Universitetskiy-Tatiana” satellite observations

The Russian microsatellite “Universitetskiy-Tatiana” was launched on Jan. 20, 2005 and was both a scientific and educational mission. Its two main aims were declared as: (1) monitoring of the energetic particles dynamics in the near-Earth space environment after solar events and during quiet times, (2) educational activities based on experimental data obtained from the spacecraft. In this paper observations acquired during Dec. 5–16, 2006, known as “Solar Extreme Events 2006”, were analyzed. The “Universitetskiy-Tatiana” microsatellite orbit permits one to measure both solar energetic particle dynamics, variations of the boundary of solar particle penetration, as well as relativistic and sub-relativistic electrons of the Earth’s outer radiation belt during and after magnetic storms. Both relativistic electrons of the Earth’s outer radiation and solar energetic particles are an important source of radiation damage in near-Earth space. Therefore, the presented experimental results demonstrate the successful application of a small educational spacecraft both for scientific and educational programs.     

Selection of candidate salad vegetables for controlled ecological life support system

Higher plants, as one of the essential biological components of CELSS, can supply food, oxygen and water for human crews during future long-duration space missions and Lunar/Mars habitats. In order to select suitable leaf vegetable varieties for our CELSS Experimental Facility (CEF), five varieties of lettuce (“Nenlvnaiyou”, “Dasusheng”, “Naichoutai”, “Dongfangkaixuan” and “Siji”), two of spinach (“Daye” and “Quanneng”), one of rape (“Jingyou No. 1”) and one of common sowthistle were grown and compared on the basis of edible biomass, and nutrient content. In addition, two series of experiments were conducted to study single leaf photosynthetic rates and transpiration rates at 30 days after planting, one which used various concentrations of CO₂ (500, 1000, 1500 and 2000 μmol mol⁻¹) and another which used various light intensities (100, 300, 500 and 700 μmol m⁻² s⁻¹). Results showed that lettuce cvs. “Nenlvnaiyou”, “Siji” and “Dasusheng” produced higher yields of edible biomass; common sowthisle would be a good source of β-carotene for the diet. Based on the collective findings, we selected three varieties of lettuce (“Nenlvnaiyou”, “Dasusheng” and “Siji”) and one of common sowthistle as the candidate crops for further research in our CEF. In addition, elevated CO₂ concentration increased the rates of photosynthesis and transpiration, and elevated light intensity increased the rate of photosynthesis for these varieties. These results can be useful for determining optimal conditions for controlling CO₂ and water fluxes between the crops and the overall CELSS.     

Estimated errors in a global gravity wave climatology from GPS radio occultation temperature profiles

In a previous paper by Schmidt et al. (2008), from CHAllenging Minisatellite Payload (CHAMP) Global Positioning System (GPS) radio occultation data, a comparison was made between a Gaussian filter applied to the “complete” temperature profile and to its “separate” tropospheric and stratospheric height intervals, for gravity wave analyses. It was found that the separate filtering method considerably reduces a wave activity artificial enhancement near the tropopause, presumably due to the isolation process of the wave component. We now propose a simple approach to estimate the uncertainty in the calculation of the mean specific wave potential energy content, due exclusively to the filtering process of vertical temperature profiles, independently of the experimental origin of the data. The approach is developed through a statistical simulation, built up from the superposition of synthetic wave perturbations. These are adjusted by a recent gravity wave (GW) climatology and temperature profiles from reanalyses. A systematic overestimation of the mean specific wave potential energy content is detected and its variability with latitude, altitude, season and averaging height interval is highlighted.     

The thermospheric composition different responses to geomagnetic storm in the winter and summer hemisphere measured by “SZ” Atmospheric Composition Detectors

Three “SZ” Atmospheric Composition Detectors (ACDs) on board spacecraft “SZ-2”, “SZ-3” and “SZ-4” were launched on 10th January 2001, 26th March 2002 and 31st December 2002 separately. A large quantity of thermospheric composition data at the orbital altitude ranging from 330 to 362 km were collected from the in-situ measurement of ACDs. The spacecrafts’ lifetime was just in the second peak period of the 23rd solar cycle which includes two peaks and the solar activity value F_10.7 was from 89 to 228. During this period, several intense geomagnetic disturbances happened.     

“Oblique” Bernstein modes in solar preflare plasma: Generation of second harmonics

Process of second harmonics generation due to development of corresponding instability has been investigated for pure electron weakly oblique Bernstein mode. This mode was supposed to be modified by taking into account the influence of pair Coulomb collisions and weak large-scale electric field in flare loop. Investigated area was located near the loop foot-point in the “lower–middle” chromosphere of active region. It has been shown, that for the Fontenla–Avrett–Loeser model of solar atmosphere the investigated process of second harmonics generation starts at the extremely low threshold values of subdreicer electric field, well before the beginning of “preheating” phase of flare process.     

The use of MODIS 250 m bands to improve the MODIS 1 km ocean color atmospheric correction algorithm in turbid water

“Clear water” is a scale-dependent concept, so it is more likely to successfully find the “clear water” from images with smaller scale than that with larger scale data. In this study, an optimal spectral relationship of moderate-resolution imaging spectroradiometer (MODIS) 250 m and 1 km resolution data at near-infrared bands (OSRLM) is constructed for converting pseudo “clear water” reflectance at 859 nm to those at 748 and 869 nm. According to scale effects, the satellite-observed pseudo “clear water” reflectance is greater than 5.18%, larger than that derived from OSRLM model. An atmospheric correction model for MODIS 1km data using pseudo “clear water” reflectance of MODIS 250 m data (ACMM) was developed for improving the performance of traditional “clear water” atmospheric correction model (CWAC). The model validation results indicate that ACMM model has a better performance than CWAC model. By comparison, the uncertainty decreases by 19.18% in the use of ACMM model over CWAC model for deriving water-leaving reflectance in Taihu Lake, China. This uncertainty is significantly reduced in water-leaving reflectance estimation due to partial removal of scale effects on “clear water”. These findings imply that satellite-derived aerosol scattering contribution at smaller scale usually has a better performance than that at larger scale.     

Determination of K,Ar, Cl,S, Si and Al flare abundances from RESIK soft X-ray spectra

The RESIK is a high sensitivity, uncollimated bent crystal spectrometer which successfully operated aboard Russian CORONAS-F solar mission between 2001 and 2003. It measured for the first time in a systematic way solar soft X-ray spectra in the four wavelength channels from 3.3 Å to 6.1 Å. This range includes characteristic strong lines of H- and He-like ions of K, Ar, Cl, Si, S and Al in the respective spectral channels. A distinguishing feature of RESIK is its possibility of making reliable measurements of the continuum radiation in flares. Interpretation of line and the continuum intensities observed in vicinity of respective strong lines provides diagnostics of plasma temperature and absolute abundances of K, Ar, Cl, S, Si and Al in several flares. We analyzed the observed intensities of spectral lines and the nearby continuum using the CHIANTI v5.2 atomic data package. A specific, so-called “locally isothermal” approach has been used in this respect allowing us to make not only flare-averaged abundance estimates, but also to look into a possible variability of plasma composition during the course of flares.     

Generation of secondary waves due to intensive large-scale AGW traveling

By using data from GPS receivers we detected huge-amplitude solitary large-scale traveling acoustic-gravity waves (LS AGW) which manifested themselves as perturbations of total electron content (TEC) of duration of about 40 min. Originated in the auroral area after significant alterations of geomagnetic field intensity during geomagnetic storms on 29–30 October 2003, LS disturbances propagated with a velocity about 1000–1200 m/s and caused generation of secondary small-scale (SS) waves with time period of 2–10 min. Such SS structure followed the solitary intensive AGW at a distance more than 4000 km. However, we observed such phenomenon only within the territory with high values of “vertical” TEC and steep gradients of TEC. Apparently, these conditions are necessary for generation of SS waves due to propagation of LS AGW.     

Observation bio-effect of SW-global solar radiation in Ilorin in the tropics

The annual variation of global (total) solar radiation measured over four (4) years (1995–1998) at Ilorin (8°32′N, 4°34′E) was studied and the bio-effects of the variation is herein reported. The weekly averages of the solar radiation flux were obtained and plotted. The profile of the weekly averages of the insolation shows two notable “wells” corresponding to the harmattan dry season and the rainy season. It was deduced that the duration of the seasons was directly proportional to the sizes of the “wells”, while the depths of the “wells” correspond to the severity of the causes of the “wells”. The fall and rise rates of the depth of the edges of the wells are inversely proportional to the ecological effects of the variation of the radiation. The rates of decrease and increase of the radiation flux affect the depths of the “wells” and were found to be rapid and shallow for the “Harmattan Well”, and gentle and deep for the “Rain Well”. The width (duration), rate of change and depth of the “Harmattan Well” bring about stress for both animals and plants.     

Large-scale waves in the solar corona: The continuing debate

Ten years after the first observation of large-scale wave-like coronal disturbances with the EIT instrument aboard SOHO, the most crucial questions concerning these “EIT waves” are still being debated controversially – what is their actual physical nature, and how are they launched? Possible explanations include MHD waves or shocks, launched by flares or driven by coronal mass ejections (CMEs), as well as models where coronal waves are not actually waves at all, but generated by successive “activation” of magnetic fieldlines in the framework of a CME. Here, we discuss recent observations that might help to discriminate between the different models. We focus on strong coronal wave events that do show chromospheric Moreton wave signatures. It is stressed that multiwavelength observations with high time cadence are particularly important, ideally when limb events with CME observations in the low corona are available. Such observations allow for a detailed comparison of the kinematics of the wave, the CME and the associated type II radio burst. For Moreton-associated coronal waves, we find strong evidence for the wave/shock scenario. Furthermore, we argue that EIT waves are actually generated by more than one physical process, which might explain some of the issues which have made the interpretation of these phenomena so controversial.     

Depth dose measurements with the Liulin-5 experiment inside the spherical phantom of the MATROSHKA-R project onboard the International Space Station

The Liulin-5 experiment is a part of the international project MATROSHKA-R on the Russian segment of the ISS, which uses a tissue-equivalent spherical phantom equipped with a set of radiation detectors. The objective of the MATROSHKA-R project is to provide depth dose distribution of the radiation field inside the sphere in order to get more information on the distribution of dose in a human body. Liulin-5 is a charged particle telescope using three silicon detectors. It measures time resolved energy deposition spectra, linear energy transfer (LET) spectra, particle flux, and absorbed doses of electrons, protons and heavy ions, simultaneously at three depths along the radius of the phantom. Measurements during the minimum of the solar activity in cycle 23 show that the average absorbed daily doses at 40 mm depth in the phantom are between 180 μGy/day and 220 μGy/day. The absorbed doses at 165 mm depth in the phantom decrease by a factor of 1.6–1.8 compared to the doses at 40 mm depth due to the self-shielding of the phantom from trapped protons. The average dose equivalent at 40 mm depth is 590 ± 32 μSV/day and the galactic cosmic rays (GCR) contribute at least 70% of the total dose equivalent at that depth. Shown is that due to the South Atlantic Anomaly (SAA) trapped protons asymmetry and the direction of Liulin-5 lowest shielding zone the dose rates on ascending and descending nodes in SAA are different. The data obtained are compared to data from other radiation detectors on ISS.     

Analysis of data of “Clementine” and “KAGUYA” missions and “ULCN” and “KSC-1162” catalogues

In this paper an analysis of data coordinate systems from selenographic catalogues and space missions was carried out. The lunar macrorelief models were made on basis of the software package ASNI USTU using method of the spherical harmonic expansion. These models accurately describe the global features of the lunar figure. To construct these models the following sources of topographic information were used: “Clementine” and “KАGUYА” (Selena, Japan mission) missions, “KSC-1162” (Kazan selenocentric catalogue), “Kiev” (selenodesic catalogue), “SAI” (Chuikova (1975)), “Bills, Ferrari”, “ULCN” (The Unified Lunar Control Network 2005). Direct comparison hypsometric information “KSС-1162” catalogue data with “Clementine” mission was carried out. These researches confirmed a good agreement of the hypsometric information of compared systems. The normalized coefficients were obtained on basis of the hypsometric information expansion for eight sources. The displacement of the lunar center of mass (LCM) relatively to the lunar center of figure (LCF) was obtained by using topographic data selenodetical catalogues and space missions.     

Possible Suzaku detection of non-thermal X-ray signals from a rotating magnetized white dwarf

Although rotating neutron stars (NSs) have been regarded as being textbook examples of astrophysical particle acceleration sites for decades, details of the acceleration mechanism remain a mystery; for example, we cannot yet observationally distinguish “polar cap” models from “outer gap” models. To solve the model degeneracy, it is useful to study similar systems with much different physical parameters. Strongly magnetized white dwarfs (WDs) are ideal for this purpose, because they have essentially the same system geometry as NSs, but differ largely from NSs in the system parameters, including the size, magnetic field, and the rotation velocity, with the induced electric field expected to reach 10¹³–10¹⁴ eV. Based on this idea, the best candidate among WDs, AE Aquarii, was observed with the fifth Japaneses X-ray satellite, Suzaku. The hard X-ray detector (HXD) on-board Suzaku has the highest sensitivity in the hard X-ray band over 10 keV. A marginal detection in the hard X-ray band was achieved with the HXD, and was separated from the thermal emission. The flux corresponds to about 0.02% of its spin-down energy. If the signal is real, this observation must be a first case of the detection of non-thermal emission from WDs.