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Different methods are used for the quantification of microbial load on spacecrafts. Here, we investigated a number of methodologies currently in use with the intent to identify the most accurate methods for the quantification of microbes on low-biomass metal surfaces such as those used in China's Space Station. In a previous study, we observed a high abundance of Bacillus sp. TJ 1-1 on interior surfaces of China's Space Station, and we therefore undertook this study in which we used a range of 10 2 to 10 9 cells/100 cm 2 of this strain for setting different contamination levels. Four of the most common analytical approaches (contact plate, spread plate, quantitative PCR, and BacLight™) were used to quantify the number of viable microbial cells associated with the materials of China's Space Station. Results show that, for 10 2 cells/100 cm 2 , the contact plate method is the most convenient and reliable. For microbial contamination levels ≥10 3 cells/100 cm 2 and a sampling area of 121 cm 2 , the BacLight method proved to be most reliable for the detection of live cells. Moreover, a sampling area of 121 cm 2 was found to be the most suitable for analysis of metal surfaces for space station interiors, which are usually low in biomass. These results establish suitable sampling and processing methodologies for microbial enumeration of metal surfaces on China's Space Station.

Since the early time of space travel, planetary bodies undergoing chemical or biological evolution have been of particular interest for life detection missions. NASA's and ESA's Planetary Protection offices ensure responsible exploration of the solar system and aim at avoiding inadvertent contamination of celestial bodies with biomolecules or even living organisms. Life forms that have the potential to colonize foreign planetary bodies could be a threat to the integrity of science objectives of life detection missions. While standard requirements for assessing the cleanliness of spacecraft are still based on cultivation approaches, several molecular methods have been applied in the past to elucidate the full breadth of (micro)organisms that can be found on spacecraft and in cleanrooms, where the hardware is assembled. Here, we review molecular assays that have been applied in Planetary Protection research and list their significant advantages and disadvantages. By providing a comprehensive summary of the latest molecular methods yet to be applied in this research area, this article will not only aid in designing technological roadmaps for future Planetary Protection endeavors but also help other disciplines in environmental microbiology that deal with low biomass samples.

INTRODUCTION: The previous Spacecraft Maximal Allowable Concentrations (SMACs) for methanol were established by characterizing minor effects upon cognitive functions as a no-observable adverse effects level (NOAEL). However, an increasing awareness of the risk posed by Space-Associated Neuro-ocular Syndrome (SANS) has caused NASA Toxicology to reexamine SMACs for methanol because exposure to it can also adversely affect ocular health. An updated review of the literature indicates that no adjustments to the SMACs due to SANS complications were required, while confirming that effects upon the central nervous system remain the appropriate basis for the SMACs for methanol. Our review, however, identified several issues that provide justification for modest SMAC reductions. It has recently been recognized that inhaled methanol may reach the brain via the olfactory system and be absorbed there into the highly toxic metabolite formaldehyde. A benchmark dose (BMD) for an extra risk of 10%, derived from an analysis of the incidences of neurological lesions in monkeys chronically exposed to methanol, is an order of magnitude less than the Environmental Protection Agency's (EPA's) reference concentration for chronic inhalation of methanol. Reports calling attention to the relative insensitivity of traditional methods of assessing cognitive function erode confidence that adverse effects at the concentration reported as a NOAEL would have been recognizable. Therefore, an additional modest safety factor of three is applied to SMACs for methanol. Scully RR, Garcia H, McCoy JT, Ryder VE. Revisions to limits for methanol in the air of spacecraft . Aerosp Med Hum Perform. 2019; 90(9):807-812.

Highly sensitive and rapid detection of airborne fungi in space stations is essential to ensure disease prevention and equipment safety. In this study, quantitative loop-mediated isothermal amplification (qLAMP) was used to detect fungi in the aerosol of the low-biomass environment of China's space station assembly clean room (CSSAC). A qLAMP primer set for detecting a wide range of aerosol fungi was developed by aligning 34 sequences of isolated fungal species and 17 space station aerosol-related fungal species. Optimization of sample pretreatment conditions of the LAMP reaction increased the quantitative results by 1.29-1.96 times. The results showed that our qLAMP system had high amplification specificity for fungi, with a quantifiable detection limit as low as 10 2 . The detected fungal biomass in the aerosol of CSSAC was 9.59 × 10 2 -2.20 × 10 5 28S rRNA gene copy numbers/m 3 . This qLAMP assay may therefore replace traditional colony-forming unit and quantitative PCR methods as an effective strategy for detecting fungi in space stations.

The potential applications of unmanned aerial vehicles (UAVs), or drones, have generated intense interest across many fields. UAVs offer the potential to collect detailed spatial information in real time at relatively low cost and are being used increasingly in conservation and ecological research. Within infectious disease epidemiology and public health research, UAVs can provide spatially and temporally accurate data critical to understanding the linkages between disease transmission and environmental factors. Using UAVs avoids many of the limitations associated with satellite data (e.g., long repeat times, cloud contamination, low spatial resolution). However, the practicalities of using UAVs for field research limit their use to specific applications and settings. UAVs fill a niche but do not replace existing remote-sensing methods., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

NASA has recently updated spacecraft design requirements for protecting crewmembers during dynamic spaceflight phases. The details of the update are available in a NASA publication (NASA TM-2013-217380) and are summarized here. Previously, NASA's occupant protection requirements relied primarily on the multiaxial dynamic response criterion, which NASA refers to as the Brinkley Dynamic Response Criteria (BDRC). Although simple to implement, there are several important ground rules that must be met for the injury predictions to be applicable. These include proper restraint, flail controls, proper seating support, pressure suit considerations, head protection including consideration of helmet mass, and spaceflight deconditioning. Even if these ground rules are met, there are limitations to the model that must be addressed, including: model validation, sex differences, age effects, anthropometry effects, and differences between the physical fitness of military test subjects and future crewmembers. To address these limitations, new injury assessment reference values (IARV) have been prescribed for the 5(th) percentile female and 95(th) percentile male Hybrid III anthropomorphic test devices (ATD). These metrics are head-injury criterion, head-rotational acceleration, neck injury criterion, neck-axial-force limits, flail prevention, and lumbar-axial compression force. Using these new ATD IARVs, NASA can have increased confidence that vehicle designs mitigate the risk of injury during dynamic phases of flight.

Genetic algorithm (GA) is designed to search the optimal solution via weeding out the worse gene strings based on a fitness function. GA had demonstrated effectiveness in solving the problems of unsupervised image classification, one of the optimization problems in a large domain. Many indices or hybrid algorithms as a fitness function in a GA classifier are built to improve the classification accuracy. This paper proposes a new index, DBFCMI, by integrating two common indices, DBI and FCMI, in a GA classifier to improve the accuracy and robustness of classification. For the purpose of testing and verifying DBFCMI, well-known indices such as DBI, FCMI, and PASI are employed as well for comparison. A SPOT-5 satellite image in a partial watershed of Shihmen reservoir is adopted as the examined material for landuse classification. As a result, DBFCMI acquires higher overall accuracy and robustness than the rest indices in unsupervised classification.

This article presents an account of epistemic integrity and uses it to demonstrate that the epistemic integrity of different kinds of practices in NASA's Space Shuttle Program was limited. We focus on the following kinds of practices: (1) research by working engineers, (2) review by middle-level managers, and (3) communication with the public. We argue that the epistemic integrity of these practices was undermined by production pressure at NASA, i.e., the pressure to launch an unreasonable amount of flights per year. Finally, our findings are used to develop some potential strategies to protect epistemic integrity in aerospace science.

This brief considers the attitude coordination control problem for spacecraft formation flying when only a subset of the group members has access to the common reference attitude. A quaternion-based distributed attitude coordination control scheme is proposed with consideration of the input saturation and with the aid of the sliding-mode observer, separation principle theorem, Chebyshev neural networks, smooth projection algorithm, and robust control technique. Using graph theory and a Lyapunov-based approach, it is shown that the distributed controller can guarantee the attitude of all spacecraft to converge to a common time-varying reference attitude when the reference attitude is available only to a portion of the group of spacecraft. Numerical simulations are presented to demonstrate the performance of the proposed distributed controller.

The determination of the microbial load of a spacecraft en route to interesting extraterrestrial environments is mandatory and currently based on the culturable, heat-shock-surviving portion of microbial contaminants. Our study compared these classical bioburden measurements as required by NASA's and ESA's guidelines for the microbial examination of flight hardware, with molecular analysis methods (16S rRNA gene cloning and quantitative PCR) to further develop our understanding of the diversity and abundance of the microbial communities of spacecraft-associated clean rooms. Three samplings of the Herschel Space Observatory and its surrounding clean rooms were performed in two different European facilities. Molecular analyses detected a broad diversity of microbes typically found in the human microbiome with three bacterial genera (Staphylococcus, Propionibacterium, and Brevundimonas) common to all three locations. Bioburden measurements revealed a low, but heterogeneous, abundance of spore-forming and other heat-resistant microorganisms. Total cell numbers estimated by quantitative real-time PCR were typically 3 orders of magnitude greater than those determined by viable counts, which indicates a tendency for traditional methods to underestimate the extent of clean room bioburden. Furthermore, the molecular methods allowed the detection of a much broader diversity than traditional culture-based methods.

Satellite platform vibration causes the misalignment between incident direction of the beacon and optical axis of the satellite optical communication system, which also leads to the instability of the laser link and reduces the precision of the system. So how to simulate the satellite platform vibration is a very important work in the ground test of satellite optical communication systems. In general, a vibration device is used for simulating the satellite platform vibration, but the simulation effect is not ideal because of the limited randomness. An approach is reasonable, which uses a natural random process for simulating the satellite platform vibration. In this paper, we discuss feasibility of the concept that the effect of angle of arrival fluctuation is taken as an effective simulation of satellite platform vibration in the ground test of the satellite optical communication system. Spectrum characteristic of satellite platform vibration is introduced, referring to the model used by the European Space Agency (ESA) in the SILEX program and that given by National Aeronautics and Space Development Agency (NASDA) of Japan. Spectrum characteristic of angle of arrival fluctuation is analyzed based on the measured data from an 11.16km bi-directional free space laser transmission experiment. Spectrum characteristic of these two effects is compared. The results show that spectra of these two effects have similar variation trend with the variation of frequency and feasibility of the concept is proved by the comparison results. At last the procedure of this method is proposed, which uses the power spectra of angle of arrival fluctuation to simulate that of the satellite platform vibration. The new approach is good for the ground test of satellite optical communication systems.

A regional near-infrared (NIR) ocean normalized water-leaving radiance (nL(w)(λ)) model is proposed for atmospheric correction for ocean color data processing in the western Pacific region, including the Bohai Sea, Yellow Sea, and East China Sea. Our motivation for this work is to derive ocean color products in the highly turbid western Pacific region using the Geostationary Ocean Color Imager (GOCI) onboard South Korean Communication, Ocean, and Meteorological Satellite (COMS). GOCI has eight spectral bands from 412 to 865 nm but does not have shortwave infrared (SWIR) bands that are needed for satellite ocean color remote sensing in the turbid ocean region. Based on a regional empirical relationship between the NIR nL(w)(λ) and diffuse attenuation coefficient at 490 nm (K(d)(490)), which is derived from the long-term measurements with the Moderate-resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite, an iterative scheme with the NIR-based atmospheric correction algorithm has been developed. Results from MODIS-Aqua measurements show that ocean color products in the region derived from the new proposed NIR-corrected atmospheric correction algorithm match well with those from the SWIR atmospheric correction algorithm. Thus, the proposed new atmospheric correction method provides an alternative for ocean color data processing for GOCI (and other ocean color satellite sensors without SWIR bands) in the turbid ocean regions of the Bohai Sea, Yellow Sea, and East China Sea, although the SWIR-based atmospheric correction approach is still much preferred. The proposed atmospheric correction methodology can also be applied to other turbid coastal regions.

This paper investigates the problem of output feedback attitude control of an uncertain spacecraft. Two robust adaptive output feedback controllers based on Chebyshev neural networks (CNN) termed adaptive neural networks (NN) controller-I and adaptive NN controller-II are proposed for the attitude tracking control of spacecraft. The four-parameter representations (quaternion) are employed to describe the spacecraft attitude for global representation without singularities. The nonlinear reduced-order observer is used to estimate the derivative of the spacecraft output, and the CNN is introduced to further improve the control performance through approximating the spacecraft attitude motion. The implementation of the basis functions of the CNN used in the proposed controllers depends only on the desired signals, and the smooth robust compensator using the hyperbolic tangent function is employed to counteract the CNN approximation errors and external disturbances. The adaptive NN controller-II can efficiently avoid the over-estimation problem (i.e., the bound of the CNNs output is much larger than that of the approximated unknown function, and hence, the control input may be very large) existing in the adaptive NN controller-I. Both adaptive output feedback controllers using CNN can guarantee that all signals in the resulting closed-loop system are uniformly ultimately bounded. For performance comparisons, the standard adaptive controller using the linear parameterization of spacecraft attitude motion is also developed. Simulation studies are presented to show the advantages of the proposed CNN-based output feedback approach over the standard adaptive output feedback approach.

This work intercalibrated the infrared window channels 8 (12.47 microm), 9 (11.11 microm) and 19 (3.98 microm) of the InfraRed Atmospheric Sounder (IRAS) aboard the Chinese second generation polar-orbiting meteorological satellite FengYun 3A (FY-3A) with high spectral resolution data acquired by the Atmospheric InfraRed Sounder (AIRS) aboard Aqua. A North Pole study area was selected according to the IRAS and AIRS' viewing geometry. The IRAS/FY-3A L1 data and AIRS/Aqua 1B Infrared geolocated and calibrated radiances (AIRIBRAD) in July of 2008 were used in this work. A sub-pixel registration method was developed and applied to the IRAS and AIRS images to improve the intercalibration accuracy. The co-located measurement pairs were picked out with absolute Viewing Zenith Angle differences less than 5 degrees (|Delta VZA|<5 degrees), absolute Viewing Azimuth Angle differences less than 90 degrees (|Delta VAA|<90 degrees) and absolute time differences less than 15 min (|Delta T|<15'). The results reveal that the convolved AIRS/Aqua measurements are highly linearly related to the IRAS/FY-3A measurements with correlation coefficients greater than 0.93, and calibration discrepancies exist between IRAS and AIRS channels indeed. When the brightness temperatures in IRAS/FY-3A channels change from 230.0 K to 310.0 K, the AIRS-IRAS temperature adjustment linearly varies from -3.3 K to 1.7 K for IRAS/FY-3A channel 8, from -2.9 K to 2.6 K for IRAS/FY-3A channel 9, and from -5.3 K to 1.1 K for IRAS/FY-3A channel 19.

Habitable pressurized modules, including space cabin, should provide ecologically efficient and physiologically auspicious conditions. The regenerated air should be comparable with fresh air of the natural environment humans belonged with over thousand years of evolution. Air scrubbing system GALOINHALATOR IGK-02 (MAI, patent No. 2209093) comprises eco-pure minerals from the salt rocks in Verkhnekamsk (the Urals). The portable automatic system controls air saturation with negative light aeroions and fine salt aerosols at preset levels. The laboratory, clinical and model tests demonstrated bactericide and bacteriostatic effects of air produced by GALOINHALATOR and the mineral ability to adsorb harmful volatile admixtures. Breathing decontaminated and ionized air during long stay in a pressurized module is beneficial to human performance, immunity, and chronic diseases prevention.

The paper reviews the results of efforts undertaken so far to develop three types of life support systems: fill-and-draw and physicochemical reclamation systems for space flights of up to one year in duration, and systems for more extended missions. The authors point to the engineering and logistical issues that should be given the highest priority in the next decades.

The authors substantiate the choice of a mobile telemedicine facility (MTLF) configuration for elimination of medicosanitary consequences of emergency situations fit in minibus Sobol. The global competitiveness criterion has been adapted to consider the MTLF cost-quality gain/reduction ratio in comparison with the basic model. This approach permitted determination of the vector of MTLF attributes, indices of user (doctor) satisfaction, and coefficients of significance for each MTLF vector component. The proposed competitiveness criterion and calculation procedure can be applied in optimization of the structure and composition of MTLF and other intricate telemedicine systems.

Ocean-color applications require maximum uncertainties in blue-wavelength water-leaving radiances in oligotrophic ocean of approximately 5%. Water-leaving radiances from Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite, however, exhibit temporal drift of the order of 15% as well as sensor changes in response versus scan and polarization sensitivity, which cannot be tracked by onboard calibrators. This paper introduces an instrument characterization approach that uses Earth-view data as a calibration source. The approach models the top of the atmosphere signal over ocean that the instrument is expected to measure, including its polarization, with water-leaving radiances coming from another well-calibrated global sensor. The cross calibration allows for significant improvement in derived MODIS-Terra ocean-color products, with largest changes in the blue wavelengths.

Since the first images of the sensors on board of CBERS-2 (China-Brazil Earth Resources Satellite) satellite were made available by the National Institute for Space Research (INPE), users have asked information about the conversion of image digital numbers to physical data (radiance or reflectance). This paper describes the main steps that were carried out to calculate the in-flight absolute calibration coefficients for CBERS-2 CCD level 2 (radiometric and geometric correction) images considering the reflectance-based method. Remarks about the preliminary evaluation of these coefficients application are also presented.

One of the main tasks of NASA's planetary protection program is to prevent the forward contamination of extraterrestrial environments with Earth life, and in turn preserve other planets and the integrity of future life detection missions. Despite information regarding bacterial diversity in NASA's clean rooms, little is known about the presence of Archaea. Archaeal community analysis of spacecraft-associated surfaces is important, as they are considered by some to represent terrestrial life most capable of surviving on Mars. The first insights into the archaeal diversity of clean rooms where spacecraft assembled are attempted. Nucleic acid sequences clustering with uncultivable Archaea within the Eury- and Crenarchaeota were retrieved from 8 of 26 samples collected from several spacecraft assembly clean rooms. Due to their potential capability to survive and proliferate in Martian conditions, screening for Archaea on spacecraft surfaces and instruments that are associated with future life detection missions may be necessary.

With 5-7 month long duration missions at 51.6 degrees inclination in Low Earth Orbit, the ionizing radiation levels to which International Space Station (ISS) crewmembers are exposed will be the highest planned occupational exposures in the world. Even with the expectation that regulatory dose limits will not be exceeded during a single tour of duty aboard the ISS, the "as low as reasonably achievable" (ALARA) precept requires that radiological risks be minimized when possible through a dose optimization process. Judicious placement of efficient shielding materials in locations where crewmembers sleep, rest, or work is an important means for implementing ALARA for spaceflight. Polyethylene (CnHn) is a relatively inexpensive, stable, and, with a low atomic number, an effective shielding material that has been certified for use aboard the ISS. Several designs for placement of slabs or walls of polyethylene have been evaluated for radiation exposure reduction in the Crew Quarters (CQ) of the Zvezda (Star) Service Module. Optimization of shield designs relies on accurate characterization of the expected primary and secondary particle environment and modeling of the predicted radiobiological responses of critical organs and tissues. Results of the studies shown herein indicate that 20% or more reduction in equivalent dose to the CQ occupant is achievable. These results suggest that shielding design and risk analysis are necessary measures for reducing long-term radiological risks to ISS inhabitants and for meeting legal ALARA requirements. Verification of shield concepts requires results from specific designs to be compared with onboard dosimetry., (c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.)

The National Aeronautics and Space Administration (NASA) administrator has identified protection from radiation hazards as one of the two biggest problems of the agency with respect to human deep space missions. The intensity and strength of cosmic radiation in deep space makes this a 'must solve' problem for space missions. The Moon and two Earth-Moon Lagrange points near Moon are being proposed as hubs for deep space missions. The focus of this study is to identify approaches to protecting astronauts and habitats from adverse effects from space radiation both for single missions and multiple missions for career astronauts to these destinations. As the great cost of added radiation shielding is a potential limiting factor in deep space missions, reduction of mass, without compromising safety, is of paramount importance. The choice of material and selection of the crew profile play major roles in design and mission operations. Material trade studies in shield design over multi-segmented missions involving multiple work and living areas in the transport and duty phase of space mission's to two Earth-Moon co-linear Lagrange points (L1) between Earth and the Moon and (L2) on back side of the moon as seen from Earth, and to the Moon have been studied. It is found that, for single missions, current state-of-the-art knowledge of material provides adequate shielding. On the other hand, the choice of shield material is absolutely critical for career astronauts and revolutionary materials need to be developed for these missions. This study also provides a guide to the effectiveness of multifunctional materials in preparation for more detailed geometry studies in progress., (c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.)

Objective: To verify reliability and safety of the crew support facilities on board manned spacecraft., Method: Several comprehensive qualitative and quantitative projection verification technique, such as analysis, check, demonstration, tests and reliability assessment, were used., Result: Work-items that were specified in the reliability and safety program were realized. Assurance measures for safety and reliability critical items were available. FMEA and SHA and FTA were brought in all around. Safety and reliability on equipment levels and system levels was fully carried out., Conclusion: The facility safety and reliability achieved design specification and met the requirements of spaceflight tests for manned spacecraft.

The use of a quadrupole ion trap mass spectrometer (QITMS) for quantitative analysis of hydrogen and helium as well as of other permanent gases is demonstrated. Like commercial instruments, the customized QITMS uses mass selective instability; however, this instrument operates at a greater trapping frequency and without a buffer gas. Thus, a useable mass range from 2 to over 50 daltons (Da) is achieved. The performance of the ion trap is evaluated using part-per-million (ppm) concentrations of hydrogen, helium, oxygen, and argon mixed into a nitrogen gas stream, as outlined by the National Aeronautics and Space Administration (NASA), which is interested in monitoring for cryogenic fuel leaks within the Space Shuttle during launch preparations. When quantitating the four analytes, relative accuracy and precision were better than the NASA-required minimum of 10% error and 5% deviation, respectively. Limits of detection were below the NASA requirement of 25-ppm hydrogen and 100-ppm helium; those for oxygen and argon were within the same order of magnitude as the requirements. These results were achieved at a fast data recording rate, and demonstrate the utility of the QITMS as a real-time quantitative monitoring device for permanent gas analysis., (c. 2002 American Society for Mass Spectrometry.)

The International Space Station will provide a "World Class" environment for microgravity research. Ensuring this environment requires care in all aspects of its design. These aspects include consideration of the acceleration at near-orbit-tune-periods, such as gravity gradients and station drag, as well as controlling station structural dynamic modes, mechanical disturbances, and crew disturbances. Station designers must also ensure that the required acceleration environment is provided for long duration. The microgravity requirements placed on ISS will be reviewed, along with major considerations for achieving such an environment. Further, a description of the Space Station program strategy and implementation for meeting those requirements will be discussed., (c2002 Published by Elsevier Science Ltd.)

Astronaut-centered design philosophy is a new concept suggested by the authors for manned space system design. It stems from human-centered design philosophy. Human-centered design means that human role is regarded as important basis and foundation for system design. At the beginning, the engineers used to adopt technology-centered philosophy for designing complex system, but much practice proved that the technology-centered design philosophy won't work, resulting in lower system safety and performance. So it has been currently replaced by human-centered philosophy. As examples, the principles of human-centered automation of the International Civil Aviation Organization and NASA JSC's Human-rating Requirements were introduced. At last, the astronaut-centered design philosophy and its requirements were put forward by the authors. These requirements consist of: general requirements, man-machine interaction requirements, man-environment interaction requirements and interpersonal relationship requirements.

The progress in the development of a sensor for the detection of trace air constituents to monitor spacecraft air quality is reported. A continuous-wave (cw), external-cavity tunable diode laser centered at 1.55 micrometers is used to pump an optical cavity absorption cell in cw-cavity ringdown spectroscopy (cw-CRDS). Preliminary results are presented that demonstrate the sensitivity, selectivity and reproducibility of this method. Detection limits of 2.0 ppm for CO, 2.5 ppm for CO2, 1.8 ppm for H2O, 19.4 ppb for NH3, 7.9 ppb for HCN and 4.0 ppb for C2H2 are calculated.

Objective. To study and track the reliability growth of manned spaceflight cabin-borne equipment in the course of its development. Method. A new technique of reliability growth estimation and prediction, which is composed of the Crow model and test data conversion (TDC) method was used. Result. The estimation and prediction value of the reliability growth conformed to its expectations. Conclusion. The method could dynamically estimate and predict the reliability of the equipment by making full use of various test information in the course of its development. It offered not only a possibility of tracking the equipment reliability growth, but also the reference for quality control in manned spaceflight cabin-borne equipment design and development process.

One major obstacle to human space exploration is the possible limitations imposed by the adverse effects of long-term exposure to the space environment. Even before human spaceflight began, the potentially brief exposure of astronauts to the very intense random solar energetic particle (SEP) events was of great concern. A new challenge appears in deep space exploration from exposure to the low-intensity heavy-ion flux of the galactic cosmic rays (GCR) since the missions are of long duration and the accumulated exposures can be high. Since aluminum (traditionally used in spacecraft to avoid potential radiation risks) leads to prohibitively expensive mission launch costs, alternative materials need to be explored. An overview of the materials related issues and their impact on human space exploration will be given., (Published by Elsevier Science Ltd.)

Space radiation dosimetry presents one of the greatest challenges in the discipline of radiation protection. This is a result of both the highly complex nature of the radiation fields encountered in low-Earth orbit (LEO) and interplanetary space and of the constraints imposed by spaceflight on instrument design. This paper reviews the sources and composition of the space radiation environment in LEO as well as beyond the Earth's magnetosphere. A review of much of the dosimetric data that have been gathered over the last four decades of human space flight is presented. The different factors affecting the radiation exposures of astronauts and cosmonauts aboard the International Space Station (ISS) are emphasized. Measurements made aboard the Mir Orbital Station have highlighted the importance of both secondary particle production within the structure of spacecraft and the effect of shielding on both crew dose and dose equivalent. Roughly half the dose on ISS is expected to come from trapped protons and half from galactic cosmic rays (GCRs). The dearth of neutron measurements aboard LEO spacecraft and the difficulty inherent in making such measurements have led to large uncertainties in estimates of the neutron contribution to total dose equivalent. Except for a limited number of measurements made aboard the Apollo lunar missions, no crew dosimetry has been conducted beyond the Earth's magnetosphere. At the present time we are forced to rely on model-based estimates of crew dose and dose equivalent when planning for interplanetary missions, such as a mission to Mars. While space crews in LEO are unlikely to exceed the exposure limits recommended by such groups as the NCRP, dose equivalents of the same order as the recommended limits are likely over the course of a human mission to Mars., (c2001 Elsevier Science B.V. All rights reserved.)

The design and development of crew emergency response systems, particularly to provide an unplanned emergency return to Earth, requires an understanding of crew performance challenges in space. The combined effects of psychological and physiological adaptation during long-duration missions will have a significant effect on crew performance in the unpredictable and potentially life-threatening conditions of an emergency return to Earth. It is therefore important that the systems to be developed for emergency egress address these challenges through an integrated program to produce optimum productivity and safety in times of utmost stress. Fundamental to the success of the CRV is the Environmental Control and Life Support System (ECLSS), which provides the necessary conditions for the crew to survive their return mission in a shirtsleeve environment. This article will discuss the many issues in the design of an ECLSS system for CRV and place it in the context of the human performance challenges of the mission.

Spaceflight exposes astronaut crews to natural ionizing radiation. To date, exposures in manned spaceflight have been well below the career limits recommended to NASA by the National Council of Radiation Protection and Measurements (NCRP). This will not be the case for long-duration exploratory class missions. Additionally. International Space Station (ISS) crews will receive higher doses than earlier flight crews. Uncertainties in our understanding of long-term bioeffects, as well as updated analyses of the Hiroshima. Nagasaki and Chernobyl tumorigenesis data, have prompted the NCRP to recommend further reductions by 30-50% for career dose limit guidelines. Intelligent spacecraft design and material selection can provide a shielding strategy capable of maintaining crew exposures within recommended guidelines. Current studies on newer radioprotectant compounds may find combinations of agents which further diminish the risk of radiation-induced bioeffects to the crew.

Objective. To assess and predict reliability of an equipment dynamically by making full use of various test informations in the development of products. Method. A new reliability growth assessment method based on army material system analysis activity (AMSAA) model was developed. The method is composed of the AMSAA model and test data conversion technology. Result. The assessment and prediction results of a space-borne equipment conform to its expectations. Conclusion. It is suggested that this method should be further researched and popularized.

During previous long-term manned missions, more than 100 species of microorganisms have been identified on surfaces of materials (bacteria and fungi). Among them were potentially pathogenic ones (saprophytes) which are capable of active growth on artificial substrates, as well as technophilic bacteria and fungi causing damages (destruction and degradation) to various materials (metals and polymers), resulting in failures and disruptions in the functioning of equipment and hardware. Aboard a space vehicle some microclimatic parameters are optimal for microorganism growth: the atmospheric fluid condensate with its specific composition, chemical and/or anthropogenic contaminants (human metabolic products, etc.) all are stimulating factors for the development of bacteria and mould fungi on materials of the interior and equipment of an orbital station during its operational phase(s). Especially Russian long-term missions (SALYUT, MIR) [correction of SALJUT] have demonstrated that uncontrolled interactions of microorganisms with materials will ultimately lead to the appearance of technological and medical risks, significantly influencing safety and reliability characteristics of individual as well as whole systems and/or subsystems. For a first conclusion, it could be summarized, that countermeasures and anti-strategies focusing on Microbial Contamination Management (MCM) for the International Space Station (ISS, next long-term manned mission) at least require a new materials test approach. Our respective concept includes a combined aging/biocorrosion test sequence. It is represented here, as well as current status of MCM program, e.g. continuous monitoring (microbiological analyses), long-term disinfection, frequent cleaning methods, mathematical modeling of ISS, etc.

This report describes the features of the cosmic-radiation monitoring system defined by the parameters of cosmic radiation and by the conditions of operation of dosimeters in space. The objectives of the operative and personal monitoring on board Russian spacecraft have been defined and substantiated. Accordingly, the operating characteristics of the dosimeters used during the flights of Russian manned spacecraft are given. The feasibility of perfecting the radiation monitoring facilities to be used in future manned space missions is discussed. The methods used by the Radiation Safety Service during manned space missions are described.

The Space Shuttle has a once-through water system that is initially filled on the ground, partially drained before launch and then refilled with fuel-cell generated water on orbit. The microbiological standard for the Space Shuttle potable water system during this study period allowed only 1 microbe of any kind per l00mL and no detectable coliforms. Contamination episodes in more than 15 years of Shuttle operation have been rare; however, for the past 24 missions, bacterial contamination has been detected in 33% of the samples collected 3d before launch. These samples have had on average 55CFU/100mL of bacteria, with the median less than 1CFU/100mL. Burkholderia cepacia has been the primary contaminant of the Shuttle water supply system both before and after flight. Water samples assessed during the STS-70 mission aboard the Space Shuttle Discovery were found to be contaminated (<20CFU/100mL) with B. cepacia and B. pickettii. In 1991, waste and water lines were removed from the Space Shuttle Columbia and the waste lines were found to harbor biofilms containing Bacillus spp. Nevertheless, the water systems of the four Space Shuttle vehicles provide extremely pure water.

Under existing COSPAR policy adopted in 1984, missions to Mars (landers, probes, and some orbiters) are designated as Category IV missions. As such, the procedures for implementing planetary protection requirements could include trajectory biasing, cleanrooms, bioload reduction, sterilization of hardware, and bioshields. In 1992, a U.S. National Research Council study recommended that controls on forward contamination of Mars be tied to specific mission objectives. The report recommended that Mars landers with life detection instruments be subject to at least Viking-level sterilization procedures for bioload reduction, while spacecraft (including orbiters) without life detection instruments be subject to at least Viking-level pre-sterilization procedures for bioload reduction but need not be sterilized. In light of this, it is proposed that the current policy's Category IV and its planetary protection requirements be divided into two sub-categories as follows: Category IVa, for missions comprising landers and probes without life detection experiments, which will meet a specified bioburden limit for exposed surfaces, and Category IVb, for landers and probes with life detection experiments, which will require sterilization of landed systems. In addition, Category III orbiter mission specifications are expanded to be consistent with these recommendations.

Over the last several years, the nature of the surface conditions on the planet Mars, our knowledge of the growth capabilities of Earth organisms under extreme conditions, and future opportunities for Mars exploration have been under extensive review in the United States and elsewhere. As part of these examinations, in 1992 the US Space Studies Board made a series of recommendations to NASA on the requirements that should be implemented on future missions that will explore Mars. In particular, significant changes were recommended in the requirements for Mars landers, changes that significantly alleviated the burden of planetary protection implementation for these missions. In this paper we propose a resolution implementing this new set of recommendations, for adoption by COSPAR at its 30th meeting in Hamburg. We also discuss future directions and study areas for planetary protection, in light of changing plans for Mars exploration.

Since the early eighties Spacelab has been the primary platform for experimentation under the state of virtually weightlessness (microgravity) in spaceflight. The International Space Station (ISS), planned to be operational by end of the century, will extend the scientific opportunities of Spacelab in many respects, e.g. by offering the opportunity for long lasting and continuous microgravity investigations. Stringent design and operational requirements have been defined for the ISS to keep residual accelerations as low as possible. These guidelines are based on investigations (Langbein, Alexander, and others) of upper allowable residual accelerations for most physical phenomena involved in space experiments. To meet these requirements, severe perturbations from operating the Station (reboosts to correct the orbit, docking maneuvers, etc.) are grouped outside dedicated microgravity-experiment phases. For the microgravity-phases, stringent criteria on upper limits of residual accelerations are specified. Recent predictions for the present ISS concept indicate that additional measures have to be taken. The results of the microgravity-studies on Spacelab missions (D-1, D-2, etc.) contain a wealth of valuable information for developing optimal design principles. Passive measures must be applied first ('perturbation reduction at the source' and timelining) before considering complex active isolation concepts which should be reserved for high sensitive investigations only.

Two tasks must be accomplished to provide planetary protection for Mars return missions: (1) sterilization of the scientific module to be landed on Mars and (2) reliable sterilization of all material returned to Earth, while ensuring the scientific integrity of martian samples. This paper examines similarity and differences between these two tasks, and includes a discussion of technological implementation conditions and the nature of terrestrial and hypothesized martian microflora. The feasibility of a number of chemical and physical (ultraviolet and ionizing radiation and heating) methods of sterilization for use on the ground and onboard are discussed and compared. A combination of different methods will probably be selected as the most appropriate for ensuring planetary protection on the return mission.

Mars surface in-situ exploration started in 1975 with the American VIKING mission. Two probes landed on the northern hemisphere and provided, for the first time, detailed information on the martian terrain, atmosphere and meteorology. The current goal is to undertake larger surface investigations and many projects are being planned by the major Space Agencies with this objective. Among these projects, the Mars 94/96 mission will make a major contributor toward generating significant information about the martian surface on a large scale. Since the beginning of the Solar System exploration, planets where life could exist have been subject to planetary protection requirements. Those requirements accord with the COSPAR Policy and have two main goals: the protection of the planetary environment from influence or contamination by terrestrial microorganisms, the protection of life science, and particularly of life detection experiments searching extra-terrestrial life, and not life carried by probes and spacecrafts. As the conditions for life and survival for terrestrial microorganisms in the Mars environment became known, COSPAR recommendations were updated. This paper will describe the decontamination requirements which will be applied for the MARS 94/96 mission, the techniques and the procedures which are and will be used to realize and control the decontamination of probes and spacecrafts.