Estimation of dynamic characteristics of the <Emphasis Type="Italic">International Space Station</Emphasis> from measurements of microaccelerations

We describe the results of determining the mass of the International Space Station using the data of MAMS accelerometer taken during correction of the station orbit on August 20, 2004. The correction was made by approach and attitude control engines (ACE) of the Progress transporting spacecraft. The engines were preliminary calibrated in an autonomous flight using the onboard device for measuring apparent velocity increment. The method of calibration is described and its results are presented. The error in station mass determination is about 1%. The same data of MAMS and similar data obtained during the orbit correction on August 26, 2004 were used for the analysis of high-frequency vibrations of the station mainframe caused by operation of the ACE of Progress. Natural frequencies of the ACE are determined. They lie in the frequency band 0.024–0.11 Hz. ACE operation is demonstrated to result in a substantial increase of microaccelerations onboard the station in the frequency range 0–1 Hz. The frequencies are indicated at which disturbances increase by more than an order of magnitude. The study described was carried out as a part of the Tensor technological experiment.     

Species and temperature exchange in the atmosphere of “BION-M” spacecraft

On going flights of Foton satellites allow to carry out research in the following domains: effect of space flight and outer space factors such as microgravity, artificial gravity and space radiation on physical processes and biological organisms. Experts from many Russian and foreign scientific institutions participated in the research. Over a period of time from 1973 to 1997 there were launched 11 BION satellites designed by the Central Specialized Design Bureau for carrying out fundamental and applied research in the field of space biology, medicine, radio physics and radiobiology with participation of specialists from the foreign countries.The goal of the present investigation was in developing a numerical simulator aimed at determining gas concentration and temperature fields established inside the scientific module of the spacecraft “Bion-M” and to perform optimization studies, which could meet strong requirements for air quality and temperature range allowable for operation of different biological experiments.     

Responsibility,capability, and Active SETI: Policy,law, ethics,and communication with extraterrestrial intelligence

With recently growing interest in the Active Search for Extraterrestrial Intelligence (SETI), in which humankind would send intentional signals to extraterrestrial civilizations, there have been increased concerns about appropriate policy, as well as the role of space law and ethics in guiding such activities. Implicit in these discussions are notions of responsibility and capability that affect judgments about whether humans or other civilizations should initiate transmissions. Existing protocols that guide SETI research address transmissions from Earth, but there is debate over whether these guidelines should inform de novo transmissions as well. Relevant responsibilities to address include (1) looking out for the interests of humankind as a whole, (2) being truthful in interstellar messages, and (3) benefiting extraterrestrial civilizations. Our capabilities as a species and a civilization affect how well we can fulfill responsibilities, as seen when we consider whether we will be able to reach consensus about message contents (and whether that would be desirable), and whether we have the capacity to decode messages from beings that rely on different sensory modalities. The interplay of these responsibilities and capabilities suggests that humankind should place increased emphasis on Active SETI.     

Survival of dormant organisms after long-term exposure to the space environment

The RF SRC—Institute of Biomedical Problems, Russian Academy of Sciences, developed Biorisk hardware to study the effects of long-term exposure of dormant forms of various organisms to outer space and used it to complete a series of experiments on the Russian Module (RM) of the International Space Station (ISS).The experiments were performed using prokaryotes (Bacillus bacteria) and eukaryotes (Penicillium, Aspergillus, and Cladosporium fungi), as well as spores, dormant forms of higher plants, insects, lower crustaceans, and vertebrates. The biological samples were housed in two containers that were exposed to outer space for 13 or 18 months. The results of the 18-month experiment showed that, in spite of harsher temperature than in the first study, most specimens remained viable.These experiments provided evidence that not only bacterial and fungal spores but also dormant forms of organisms that reached higher levels of evolutionary development had the capability to survive a long-term exposure to outer space. This observation suggests that they can be transferred on outer walls of space platforms during interplanetary missions.     

Structural health management technologies for inflatable/deployable structures: Integrating sensing and self-healing

Inflatable/deployable structures are under consideration as habitats for future Lunar surface science operations. The use of non-traditional structural materials combined with the need to maintain a safe working environment for extended periods in a harsh environment has led to the consideration of an integrated structural health management system for future habitats, to ensure their integrity. This article describes recent efforts to develop prototype sensing technologies and new self-healing materials that address the unique requirements of habitats comprised mainly of soft goods. A new approach to detecting impact damage is discussed, using addressable flexible capacitive sensing elements and thin film electronics in a matrixed array. Also, the use of passive wireless sensor tags for distributed sensing is discussed, wherein the need for on-board power through batteries or hardwired interconnects is eliminated. Finally, the development of a novel, microencapuslated self-healing elastomer with applications for inflatable/deployable habitats is reviewed.     

Analytic expansions of luni-solar gravity perturbations along rotating axes for trajectory optimization—Part 2: The multipliers system and simulations

An efficient self-contained trajectory optimization software is generated by making use of de Pontécoulant's analytic lunar theory removing the need for an outside third body ephemeris program to compute the lunar and solar position vectors at each integration step. The accelerations being further resolved along the rotating Euler–Hill frame after expansion to third order in the spacecraft radial distance, the adjoint differential equations are derived in a direct manner complementing the generation of the dynamic system of equations for full compatibility. Because the variation of parameters equations are cast in terms of the nonsingular equinoctial elements with the perturbation accelerations resolved in their analytic form along the rotating axes, the adjoint equations are also derived in the same manner providing a highly efficient and accurate system of equations for rapid computations in conjunction with Aerospace Corporation's NLP2 nonlinear programming codes to search for the initial values of the multipliers that steer the spacecraft towards its target orbit in minimum time. Numerical simulations show that the solutions obtained by the analysis developed in this paper are essentially identical to the more indirect approach based on the use of inertial accelerations obtained from a separate ephemeris generator and subsequent conversions to the thrust frame and equinoctial system.     

Frequency fluctuations of coherent signals from spacecraft observed during dual-frequency radio sounding of the circumsolar plasma in 2004–2008

We have performed spectral processing of the data of experiments on radio sounding of circumsolar plasma by coherent S- and X-band signals from the spacecraft Ulysses, Mars Express, Rosetta, and Venus Express carried out from 1991 to 2009. The experiments were realized in the mode of coherent response, when a signal stabilized by the hydrogen standard is transmitted from the ground station to a spacecraft, received by the onboard systems, and retransmitted to the Earth with conserved coherence. Thus, the signal sounding the coronal plasma passes twice through the medium: on the propagation path ground station — spacecraft and on the same path in the opposite direction. The spectra of frequency fluctuations in both the bands are obtained and, using them, the radial dependences of fluctuation intensities are found, which can be approximated by a power law. It is shown that the ratio of intensities of frequency fluctuations in the S- and X-bands is comparable with the theoretical value and characterizes the degree of correlation of irregularities of the electron density along the propagation path ground station — spacecraft and back. Analysis of the correlation of frequency fluctuations on the two paths allows one to get a lower estimate of the outer scale of the circumsolar plasma turbulence. For heliocentric distances R = 10 solar radii (R _S ) the outer scale is larger than 0.25R _S .     

Bacterial community in ancient Siberian permafrost as characterized by culture and culture-independent methods

The microbial composition of ancient permafrost sediments from the Kolyma lowland of Northeast Eurasia was examined through culture and culture-independent approaches. These sediments have been continuously frozen for 5,000 to 2-3 million years. A total of 265 Bacteria 16S rRNA gene sequences were amplified from the permafrost total-community genomic DNA and screened by amplified ribosomal 16S rRNA restriction analysis. Members of three major lineages were found: gamma-Proteobacteria (mostly Xanthomonadaceae), Actinobacteria, and Firmicutes. We also determined partial 16S rRNA gene sequences of 49 isolates from a collection of 462 aerobes isolated from these sediments. The bacteria included Actinomycetales (Arthrobacter and Microbacteriaceae); followed by the Firmicutes (Exiguobacterium and Planomicrobium); the Bacteroidetes (Flavobacterium); the gamma-Proteobacteria (Psychrobacter); and the alpha-Proteobacteria (Sphingomonas). Both culture and culture-independent approaches showed the presence of high and low G+C Gram-positive bacteria and gamma-Proteobacteria. Some of the 16S rRNA gene sequences of environmental clones matched those of Arthrobacter isolates. Two-thirds of the isolates grew at -2.5 degrees C, indicating that they are psychroactive, and all are closely related to phylogenetic groups with strains from other cold environments, mostly commonly from Antarctica. The culturable and non-culturable microorganisms found in the terrestrial permafrost provide a prototype for possible life on the cryogenic planets of the Solar System.     

Ultrastructural study of iron oxide precipitates: implications for the search for biosignatures in the Meridiani hematite concretions, Mars

Two terrestrial environments that have been proposed as analogs for the iron oxide precipitation in the Meridiani Planum region of Mars include the Rio Tinto precipitates and southern Utah marble concretions. Samples of two typical Utah iron oxide concretions and iron oxide precipitates in contact with biofilms from Rio Tinto have been studied to determine whether evidence could be found for biomediation in the precipitation process and to identify likely locations for fossil microorganisms. Scanning electron microscopy, energy dispersive X-ray, and gas chromatography-mass spectrometry (GC-MS) were used to search for biosignatures in the Utah marbles. The precipitation of iron oxides resembles known biosignatures, though organic compounds could not be confirmed with GC-MS analysis. In contrast, textural variations induced by biological activity are abundant in the modern Rio Tinto samples. Although no compelling evidence of direct or indirect biomediation was found in the Utah marbles, the ultrastructure of the iron oxide cement in the concretion suggests an inward growth during concretion precipitation from an initially spherical redox front. No indication for growth from a physical nucleus was found.     

Spectral properties of Lake Superior banded iron formation: application to Martian hematite deposits

Several locations have been identified on Mars that expose bulk, coarsely crystalline gray hematite. These deposits have been interpreted as being sedimentary and formed in aqueous environments. Lake Superior Type (LST) banded iron formation (BIF) was investigated as a spectral and possible process analog to these deposits. In northern Michigan, LST BIF formed in a sedimentary, continental shelf or shallow basin environment under stable tectonic conditions, and the oxide facies contains gray, crystalline hematite. These deposits are Proterozoic in age and contain microfossils associated with the early diversification of life on Earth. Samples of the hematite-bearing oxide facies, as well as the carbonate facies, were collected and analyzed for their spectral and geochemical characteristics. Sample spectra were measured in the visible, near-infrared, and thermal infrared for comparison with remote and in situ spectra obtained at Mars. Thin section analysis, as well as X-ray diffraction and scanning electron microscopy measurements, were performed to determine detailed geochemistry. There is no evidence for BIF at Opportunity's Meridiani landing site, and the results of this work will provide useful data for determining whether BIFs exist elsewhere on Mars and are, thus, relevant to current and future Mars exploration missions.