Engineering, Construction, and Operations in Challenging Environments: Earth and Space 2004

The constitutive behavior of Martian regolith was studied by conducting a series of conventional triaxial compression experiments on JSC Mars-1 simulant. The results of the experiments were used to calibrate an elasto-plastic constitutive model known as Lade's model. The model was implemented into the ABAQUS finite element program and used to predict the behavior of the regolith simulant. The model predictions compares well with the experiments. The model was used to investigate the behavior of JSC Mars-1 simulant under very low confining pressure (0.1kPa) and reduced gravity (3/8g). The increase in the self weight of the soil was found to increase the dilation and the deviatoric stress at failure.

The structure for the human habitat in either a lunar or Martian base must be efficient, reliable, functional and economical. In addition to the specific needs for structural adequacy and efficiency, the structure must be consistent with the overall habitat design by being supportive of other critical criteria, including minimal stowage mass and volume, ease of deployment and minimal associated astronaut time and construction equipment, integration of the structure with the habitat operations and life support systems, and the outfitting and placement of contents within the habitat. The conceptual design of a proposed structural configuration addressing these criteria is described, including through computer-generated visualization, some preliminary calculations, and examination of major design concerns. The basic unit of the modular system proposed is a three-level 9-meter diameter inflatable membrane spherical shape shipped stowed around a core containing extendable side and top/bottom support members and rings, along with other structural members, equipment, and stable habitat supplies. Much of the deployment on site is accomplished through pressurization of the unit as this pulls the support members and the rings attached to membrane from the core and into position. An internal support rib system adjacent to the membrane and spanning between the support rings, along with other interior structural elements and fixtures, are placed by the mission members in a pressured environment. The system is designed to minimize deployment and outfitting effort, shipping volume, and the need to move materials through an airlock into the pressurized module. Adjacent modules are joined structurally and functionally through the side rings.

Mankind has set foot on the Moon over three decades ago. Ever since then, NASA and other space agencies have planned to build an outpost on the Moon for changing reasons. Was it to show the technical advances of the US during the Cold War at first, today's reasons for a base on the Moon are more practical: Astronomy, Mining or Tourism are possible arguments for a human presence on Earth's only natural satellite. This paper summarizes environmental issues and other boundary conditions, a classification of structural concepts being considered for the Moon and challenges for future research. Some preliminary considerations on a lunar design are also presented.

The demand for new buried utilities is growing with new construction, reconstruction, and the growth of the subsurface infrastructure worldwide. As a result, contractors are busy digging and trenching into the ground in order to bury new pipes. Because the machinery for placing the new utilities underground, such as backhoe excavators, trenchers, augers, drills, and plows, don't "feel" when they are getting close to already buried object, utilities are easily damaged. Despite great efforts in locating existing utilities before a contractor is allowed to dig, accidents occur in great numbers. A key problem of the presently available hand-held technologies to detect underground utilities before digging is the inability to reliably predict the exact location (e.g., depth) of existing utilities. One particularly difficult problem represent plastic pipes that are being used to deliver gas in neighborhood networks. Currently no reliable technology exists that will provide accurate information about the location of buried gas pipes. One promising exception is ground penetrating radar (GPR) that has received a lot of attention by researchers to find mines made mostly of plastic. Its electromagnetic pulses are being reflected by changing density and works best when the target object is very dense compared to the surrounding (e.g., steel bar in soil.) However, plastic pipes filled with gas are dielectrically less dense thus offering a special challenge for GPR. In 1993, the Construction Automation and Robotics Laboratory (CARL) at NC State University started an initiative to address the problem of utility damages during construction. The core idea was to provide an equipment operator with his own sensing system that alerts him of a danger rather then to depend on the hand-held approach used by Underground locators today.

The use of the indigenous resources of the Moon result in the development of a power system on the moon based on the fabrication of solar cells using thin film growth technology and the vacuum environment of the Moon. The fabrication of solar cells directly on the surface of the Moon can negate the transportation of the vast arrays of cells by transporting only the tools needed to fabricate them. The deployment of a ∼200kg crawler on the surface of the Moon with the capabilities of preparation of the lunar regolith for use as a substrate, evaporation of the appropriate semiconductor material for the solar cell structure, and deposition of metallic contacts and interconnects, will allow for the emplacement of a lunar electric power system that can reach 1 MW in several years of crawler operation. This unique approach for the emplacement of an electric power system on the Moon would require the transportation of a much smaller mass of equipment to the Moon than would otherwise be required to install a power system brought to the Moon, and would result in a power system that was repairable/replaceable through the simple fabrication of more solar cells.

Microwave heating has been commonplace for over 50 years. It provides penetrating radiation, controlled electric field, rapid heating capability, and selective heating through differential coupling. While microwave ovens populate almost every kitchen, using microwave energy for materials processing is relatively new concept and is receiving greater attention that ever before. This paper describes efforts using microwave energy to process a Martian soil analog (JSC Mars-1). The goal is to directly convert iron oxide into iron with a minimum of energy and equipment. While beneficiation prior to processing will certainly create a higher quality feedstock, it is not within the scope of this paper, except in limited examples. Microwave processed samples were analyzed to determine iron content. Typically, about 10% of the iron oxide was reduced to iron using in a small crucible and a regular 800-Watt home microwave oven. Only a few minutes in the oven is required to accomplish the transformation. It is concluded that microwave energy can provide the heat necessary to reduce iron oxide. More experimentation is required to optimize parameters to increase yield and quality. It appears that microwave iron production may be feasible on Mars.

Construction of permanent settlements on the Moon will be greatly facilitated by the use of local building materials. The structural materials normally employed in Terrestrial construction (steel, Portland Cement concrete, wood and masonry) are to a great extent unavailable on the Moon. (Steel and Lunar-style masonry may eventually be fully available — but concrete requires large quantities of water, and wood will not be an option.) The Lunar surface does, however, feature large quantities of basaltic rock, which is already employed on Earth as an industrial material. Cast Basalt has many desirable structural properties — yet its ultimate failure mode is brittle fracture, especially under bending loads, which is highly undesirable. This design note will discuss one option for scaling up Terrestrial experience with Cast Basalt as an industrial material, to use in larger castings for structural construction on the Moon. Post-tensioning of the basaltic castings, based on Terrestrial experience with reinforced concrete structures, will be outlined. Post-tensioning will enhance the use of these elements for building crewed habitations. Using a tensile material to compress the more brittle basaltic casting will transform the combined structural element from a brittle into a ductile material, for purposes of structural design and risk evaluation. In the Lunar environment, with internal air pressure being the dominant loading for inhabited structures, ductility of the structural elements will be a vital need.

Addition of short fibers to a granular medium can increase the shear strength of the composite. This is a desired effect in applications such as roads and airfields, mitigation of failed slopes, but also it might become a useful construction technique in extraterrestrial environments. Some results from the triaxial testing of fiber-reinforced sand are shown, and a method for developing a failure criterion is presented briefly. The failure criterion is found in closed form, and it is illustrated as a surface in the stress space. The theoretical prediction of failure stress falls surprisingly close to the experimental test results. A convenient way is shown for representing the strength of the fiber-reinforced granular composite using a substitution (or macroscopic) internal friction angle.

A direct tension apparatus and experimental procedures were developed. This technique requires no power or sophisticated data acquisition, and it is able to simply measure the tensile strengths of moist sands and should make it possible for engineers wishing to include tensile strength in their soil behavior models to do so in a coherent way, linking model parameters to laboratory data. Experiments were carried out to examine the variation of tensile strengths on sands at different water content levels up to 18%. The magnitudes of the tensile strengths at even very low moisture contents are not equal to zero, as is widely assumed. Tensile strength increases with increasing water contents until about 15% and beyond this point the strength decreases. The influences of relative density and fines on the tensile strength are observed, but substantially dependent on the water content.

Interface shear zones between particulate materials and continuum elements of man-made or natural materials have not been traditionally considered as shear bands. However, the results of recent micro-scale experimentation and numerical simulations have shown that they are indeed well developed partial shear bands. Further, these studies have indicated that significant similarities can be identified between these partial shear bands and what are more traditionally considered to be shear bands that evolve wholly within particulate materials. This paper presents results from physical and numerical experiments that suggest there is significant merit to this opinion. The physical experiments include quantitative analysis of the particle deformation following shear adjacent to continuum surfaces of different roughness as well as analyses of sand specimens sheared to different global strain levels. Complimentary 2-D Discrete Element Method modeling of particulate-continuum surface interfaces illustrates this parallel behavior.

The objective of the study presented here is to develop a constitutive model for granular materials based on the consideration of its microstucture. By analyzing a microelement based on four spheres, equations governing the equilibrium of the microelement are developed. By examining these equations more closely, two primary mechanisms of failure of the microelements, one based on particle sliding and another based on particle rolling, are identified. For each primary mechanism, two separate mechanisms, one based on collapse of the microelement in the vertical direction and the other based on collapse in the horizontal direction, are recognized. With the aid of these concepts, constitutive equations are developed for a two dimensional assembly of granular particles. The assembly is considered to consist of the 4-sphere microelements. Taking the plastic strains to be consequence of the collapse of some of the microelements, equations are developed for plastic strains. The formulation yields loading criteria and flow directions. With suitable hardening rules, it is shown that the microstructural model is capable of simulating most of the salient features of the stress-strain behavior of granular materials. In particular, the stress-dilatancy relation with consideration to the phenomena of phase transformation and critical state failure are simulated satisfactorily.

The presentation focuses on different sets of drained and undrained cyclic triaxial experiments on loose and dense cylindrical specimens of subangular quartz sand, which were conducted under displacement control at very low effective stress levels. The experiments were motivated by the need to enhance our understanding of low-stress phenomena and mechanical properties of both terrestrial soils and regolith on the Moon and Mars subjected to low gravity conditions. The first two sets of experiments were conducted under drained conditions on NASA Space Shuttle (STS-79, 1996; and STS-89, 1998) under microgravity conditions, and the last set was recently conducted on Columbia (STS-107) in January, 2003. In the case of the drained experiments, the effective confinement pressures were held constant throughout the experiments, and they were in the range of 0.05 to 1.30 kPa, which in the case of the undrained experiments these same effective stress levels comprised the initial states. The initial relative densities of the specimens were in the range of 35% to 85%. In the drained experiments we observed peak friction angles as high as 72°±2° together with dilatancy angles in the range of 30° ±1°. Constant-volume friction angles of 34 ±1 degrees were recorded at relatively high strain levels in all the drained experiments. Transitions from a stable solid to a viscous liquid state (liquefaction) were observed in several undrained experiments at very low initial density states, however, in several cases dilative behavior was observed at very low effective stresses as well as low initial relative densities (35–45%). For several of the specimens extensive computed tomography records were obtained, which show complex patterns of shear band formation, which usually emerged at levels of 2–3% axial strain after peak strength had been reached. The presentation will focus on experimental technique, observations and data, as well as computed tomography data, and modeling results.

A model-based, distributed architecture integrates diverse components in a system designed for lunar and planetary surface operations: spacesuit biosensors, cameras, GPS, and a robotic assistant. The system transmits data and assists communication between the extra-vehicular activity (EVA) astronauts, the crew in a local habitat, and a remote mission support team. Software processes ("agents"), implemented in a system called Brahms, run on multiple, mobile platforms, including the spacesuit backpacks, all-terrain vehicles, and robot. These "mobile agents" interpret and transform available data to help people and robotic systems coordinate their actions to make operations more safe and efficient. Different types of agents relate platforms to each other ("proxy agents"), devices to software ("comm agents"), and people to the system ("personal agents"). A state-of-the-art spoken dialogue interface enables people to communicate with their personal agents, supporting a speech-driven navigation and scheduling tool, field observation record, and rover command system. An important aspects of the engineering methodology engineering involves first simulating the entire hardware and software system in Brahms, and then configuring the agents into a runtime system. Design of mobile agent functionality has been. based on ethnographic observation of scientists working in Mars analog settings in the High Canadian Arctic on Devon Island and the southeast Utah desert. The Mobile Agents system is developed iteratively in the context of use, with people doing authentic work. This paper provides a brief introduction to the architecture and emphasizes the method of empirical requirements analysis, through which observation, modeling, design, and testing are integrated in simulated EVA operations.

To enable human exploration of the solar system in the next decade, demonstration of the technologies to support the survival and function of the carbon-based occupants needs to conducted, utilizing reasonably high fidelity analog environments. Operational issues may be best evaluated and improved in topographically and climatically similar conditions to the planetary surface. Earth-based mission support operations can be simulated for planetary exploration in an exploration payload operations center (ExPOC) with appropriate communication time delays. Surface habitat issues may best be resolved in closed life support chambers, where the performance of each subsystem for air, water and energy management can be evaluated and integrated. Testing of both physiochemical and bioregenerative systems alone and in combination, along with evaluation of the effect of the life support system (LSS) on human health and function, is required to prepare such systems for planetary exploration. A thorough review of the key life and health sustaining issues for planetary exploration is the starting point for LSS and medical support system (MSS) design refinement.

The labor-intensive construction industry has a very high accident rate. One of the key reasons for this is the exposure of workers to a hazardous environment such as heights, confined narrow spaces, and exposure to health threatening fumes, dust, and noise. The installation of utilities underground was necessitated by the emergence of centers of population, such as cities and villages. On one hand, water had to be brought to the centers from afar and on the other hand, wastewater had to be removed in order to avoid diseases. It can be expected that similar pipelines will be found most effective when constructing habitats on the surface of extraterrestrial bodies. Due to the problems from working in for an extended period in space, the construction and installation of those lines will most likely require a robotic approach. This paper will review construction technologies that have been developed over time before discussing a tele-robotic approach that eliminates the need for laborers to enter and work in tight subsurface space. The two remotely controlled manipulators allow the installation of concrete pipes with up to 1.65 m (5 ft.) in diameter and smaller plastic pipes.

Robotics provide a safe alternative to the extremely hazardous and labor-intensive Humanitarian Demining (HD) operations that are conducted manually. The need for safe and easy-to-operate systems to facilitate the detection and neutralization of landmines is being addressed through the design and development of a remotely operated system. The system will support operations to detect and clear mined areas in an effort to ensure the safe release of these areas for reoccupation by indigenous people. A Remote Control System (RCS) will be incorporated on a light, utility-tracked vehicle to provide remote operation of all vehicle functions. The RCS will also provide operation of any equipment or tools integrated onto the robotic platform, including detection and neutralization components. Operation of the system will be conducted remotely through Radio Frequency (RF) communication from an Operator Control Station (OCS). The operator, stationed a safe distance away from the minefield, will conduct all HD operations through the OCS, which provides joystick controls to operate system functions, video feedback from the platform, and a touch-screen for additional information and control features.

Safety is one of the foremost issues in the operation of heavy equipment because of its impact on the construction industry. According to the Occupational Safety and Health Administration (OSHA), a significant percentage of all fatalities in the construction industry stemmed from incidents involving the operation of heavy equipment. One of the major causes of these fatalities is the lack of safety features installed on the heavy equipment that is currently in use. The objective of the research described herein is to develop a human-assisted obstacle-avoidance system with a 3D workspace model. Human-assisted obstacle avoidance system is proposed and algorithms for obstacle avoidance system such as artificial potential function and minimum distance algorithms are presented as well as algorithms for 3D workspace modeling such as convex hull algorithm and workspace partitioning algorithm. Preliminary results of simulation of obstacle avoidance system are presented.

Mobility of the micro lunar rover has become one of the major research subjects for Japan's first lunar surface mission, as its planning efforts shifted to a detailed design phase. The experimental and analytical studies on the mobility of the lunar rover have been thus performed to evaluate traveling performance of the driving gear of the rover, and to design an optimal mechanism suitable for moving on regolith. Experiments were conducted both in full-scale and 1/6-scale models using wheel traveling apparatuses, and relationships between the mobility of wheels and traveling conditions were obtained. A simulation model of the wheel-soil system was developed by using two-dimensional Distinct Element Method (DEM). It was confirmed that the developed DEM model satisfactorily analyzed the mechanical relationship of the wheel mobility. Results of these experimental and analytical studies will contribute to the design the driving mechanism of a micro lunar rover.

This paper describes the robotic assembly for the very large-scaled structures such as space solar power system. The technological challenges toward its autonomous assembly are discussed. The ground testbed developed in JAXA for confirming feasibility and the ground experiments for assembling the flexible structures are described.

This article describes the development of a high temperature and harsh environment compatible packaging solution for microsensors. It is based on the stacking of different layers with matched coefficients of thermal expansion. Careful selection of solder materials with appropriate soldering temperatures allow assembly of the sensor element and the complete stack housing with only two main soldering steps. Testing the sensor and comparing the results with a reference sensor demonstrated the potential of the developed concept.

This paper describes a control system using different sensor modalities for moving a tracked vehicle from a starting position to a goal position. The system includes a path planner, a path-tracking controller, a cross-coupling controller and a vision based slippage controller. Experiments are conducted to test and verify the performance of the presented system.

Using robots to supplement human rescuers in the urban search and rescue arena has been a topic of intense research over the last several years. This paper describes the rationale for using robotic rescue teams, both in the real world and in the annual RoboCup Rescue competitions. In particular, the design of a graphical user interface that provides a different view of sensor data depending on the needs of the user is described. This GUI integrates sensor data from multiple robots to provide a probability estimate for the location of items of interest in the environment. The design of the GUI is described in detail, along with an implementation of the GUI on a pair of commercially available robots with multiple sensors operating in a simplified rescue environment. A plan for future work is also presented.

This paper investigates the through-thickness and in-plane constraint effects on mode I fatigue crack growth under small-scale yielding regime. The finite element analyses demonstrate the existence of a similarity scaling relationship that couples in a unique way the opening stress intensity factor to peak load in each cycle, the specimen thickness, the in-plane constraint level and the material flow properties. Through surface contact maps, the results illustrate the 3-D opening process and the effects of in-plane constraint levels on the through-thickness opening-closing behavior.

FRP laminates have the special characteristics of high ratio of elastic modulus to shear modulus (i.e. 20 < E/G < 50) compared to that for isotropic case ( 0 < E/G < 3). Shear stiffness of these materials is very small compared to their membrane and bending stiffnesses. As a result, shear deflection plays a pronounced role in the gross behavior of laminated composite structures. This paper presents an overview of the higher order shear deformation theory developed for the analysis of stiffened and un-stiffened laminated composite plates. While there exist large number of analytical prediction theories, there is limited experimental validation of some of the analytical method developed. Tests were carried out to verify the analytical model experimentally. Some of the critical observations made during the experimental phase are reported and discussed.

In this paper, an approach to detect and isolate the aircraft sensor/control surface faults affecting the mean of the Kalman filter innovation sequence is proposed, and a new structure for a fault tolerant aircraft control system is presented. In the simulations, the longitudinal and lateral dynamics of an F-16 aircraft model is considered, and detection and isolation of pitch rate gyro faults and control surface faults are examined. The principal block diagram of a fault tolerant aircraft control system is illustrated.

Magnetoelastic interactions in conducting beams arc studied experimentally and numerically as a possible means for active vibration suppression mechanism in structural control. The experimental apparatus involves a cantilevered beam made of flexiglass which is placed in between two poles of a magnet. The desired effect of magnetoelastic interaction in the beam is provided by a concentric coil attached to the face of the beam and the magnetic field generated by the horn magnet. The electromagnetic damping control system works based on the concept of negative feedback. The vibration is shown to be reduced significantly although only a small amount of electric current is supplied to the coil. The experiment is then analytically modeled using the Faraday's law and the resulting electromotive force acting on the beam and cast into a nonlinear initial boundary value problem. The resulting nonlinear problem is then solved numerically using the finite difference method. Experimental results are consistent with the analytical study and demonstrate the controllability of beams using the magnetoelastic interaction. An effective damping factor due to the magnetic damping is suggested based on the energy balance. Promises and limitations of the proposed control strategy are also discussed.

Building aerodynamics is one of the major component in determination of wind effects on buildings. Most of the aerodynamic effects are obtained through measurements in wind tunnels. A limited number of tests are performed on a full-scale level because of difficulty in conducting tests and the high cost. This paper summarizes type of measurements, instrumentation and data for full-scale measurements. The actual presentation with typical photographs and data will be placed on the web site following the conference.

The face of structural engineering is being transformed through emerging information and sensor technologies that allow real-time, remote monitoring of structures to new levels of precision, all helping to further enhance the state-of-the-art. By integrating innovative developments in web programming and remote host configurations with high precision sensors like real-time kinematic (RTK) global positioning systems (GPS), data can be mined from structures excited within actual wind and earthquake environments for study of response characteristics, in-situ dynamic properties, and even day-to-day management and operation of critical infrastructure. This paper showcases one application towards this end—a unique program systematically validating the observed full-scale performance of several tall buildings in the US against the wind tunnel and finite element models used in their design.

The application of advanced satellite and airborne remote sensing imaging technologies, including optical, radar, and lidar sensors, to the task of response and recovery from natural and man-made disasters, has received considerable interest in recent years. As geospatial information product developers attempt to put these technologies to work in real world situations, they face a number of policy and institutional hurdles. This paper focuses on policy and institutional issues that affect the use of satellite technologies in response to and recovery from earthquakes, hurricanes, tornados, and other natural disasters. It also explores the use of these technologies for responding to manmade disasters such as war, refugee movements, and environmental degradation.

Remote sensing technology has been widely recognized for contributing to emergency response efforts after the World Trade Center Attacks on September 11th, 2001. The need to coordinate an event of this magnitude in a dense yet relatively small area made the combination of imagery and data maps very powerful. This paper introduces aerial imagery, satellite imagery, and LIDAR data use at Ground Zero. It examines how emergency managers used the data, how it might have been used, and what needs to be done to ensure effective use in the future. In order to plan adequately for future events, it was important to capture knowledge from those who responded to the World Trade Center. Interviews with key emergency management and GIS personnel provide the basis of this paper. Successful techniques should not be forgotten and problems encountered should not be dismissed. Although widely used after September 11th, it is important to recognize that with better planning, remote sensing and GIS could have played an even greater role.

In the past decades, many urban areas around the world have been experiencing a dramatic increase in disaster due to flood. Flood is one of the extreme hydrological events which has been a major concern since the dawn of human civilization. Especially the flash flood, it can cause the greatest number of deaths and the greatest damage in a sudden. The impact of flood on people's livelihood may be much longer than the water take to recede. The effect of lost and degraded assets can also have very much long-term impact on society and ecosystems. It is obvious that flood incident has become the limiting factor to economic and social development. Therefore, various efforts have been set out for establishment of the proper prevention and mitigation to reach sustainable level to relief flood stress in such a way that avoid the past mistakes and satisfy the widest range of needs and maintain the natural ecosystem. The current situation to cope with this type of water related extreme event is diversified into four levels, namely disaster preparedness, prevention and mitigation, emergency response and disaster recovery. Among promising response strategies, the role of forecast and warning system is widely taken into consideration in several research studies to contribute to the systematic preparedness of urban flood management. This calls for a sequence of several steps, namely establishing an effective monitoring to detect all possible formation of storm through meteorological conditions and hydrological process which may lead to the extreme event. Future river flow condition and water stage are forecasted on the place, time, magnitude, areal extension, duration and time span of crisis based mathematical modeling including meteorological, hydrological and hydraulic models. Warning is sent to the appropriate authorities and to the public. The population at risk and the authorities responsible for the defense responds to the warning. Finally, assistance during and after the disaster hit is taken place, eg. provision of food, drinking water, shelter and medical care including reconstruction of infrastructure, rehabilitation of the environment and of the defense system. The challenge lies in the improvement of meteorological model to assess in detail the location and the magnitude of rainfall especially the local convective heavy thunderstorm that may cause flash flood.

The purpose of this study is to demonstrate the application of SAR imagery technology to the detection of changes and damage in urban areas, with particular emphasis on changes caused by natural and manmade disasters. Synthetic Aperture Radar (SAR) provides high quality images in all weather and all time conditions. It shows promise for acquiring spatial and temporal high-resolution data for urban damage detection. SAR simulation of real-sized structures (including bridges and buildings) is proposed first as a proof of concept to demonstrate the usefulness of SAR applications and its imaging potentials and characteristics relevant to urban areas. The second objective of this research is to study the capabilities of damage and change diagnostic schemes based on simulated complex SAR images of pre- and post-events, A SAR image is obtained from a coherent imagery system, it can be described in three dimensions, sometimes referred to as a complex imagery system, whereby two dimensions represent the image and the third dimension represents the phase content of the image. The phase information is relevant to the detection of the finer details in the image. A library of SAR signal responses on buildings and structures are also being compiled.

An automated in-situ road surface distress inspection and management system is developed on the basis of remote sensing and geographic information management technique within a GIS framework. ArcGIS platform is implemented to integrate the routines of image processing and spatial analysis in handling the full-scale metropolitan highway surface distress detection and data fusion/management. This makes it possible to present user-friendly interfaces, to incorporate GPS and remote sensing techniques in GIS and to provide efficient visualizations of surveyed results not only for the use of transportation engineers to manage road inspection documentations, data acquisition, analysis and management, but also for financial officials to plan maintenance and repair programs and further evaluate economic impacts of highway degradation and deterioration.

For several years, a Multidisciplinary Center for Earthquake Engineering Research (MCEER) team has been investigating the use of remote sensing technology for post-earthquake damage detection and emergency response. This research has focused on various aspects of damage detection including: (1) the basic distinction between damage, versus non-damage on a regional basis; (2) the quantification of various damage states on a city wide basis; and (3) the assessment of damage sustained by specific buildings. This paper introduces methodological procedures for characterizing urban building damage using optical SPOT4 and ERS Synthetic Aperture Radar (SAR) remote sensing imagery. Preliminary damage detection algorithms are introduced for the 1999 Marmara earthquake in Turkey, demonstrating the ability of advanced technologies to identify urban damage, and thereby determine the scale of a disaster. A quantitative assessment is made of the magnitude and extent of building collapse within the city of Golcuk, using `damage profiles'. The evaluation of damage on a per-building basis requires higher resolution imagery, which was unavailable for the Marmara event. This topic is instead being addressed through an ongoing study of Quickbird imagery for the 2003 Boumerdes, Algeria earthquake. The significance of these findings is far-reaching. In terms of benefits to emergency responders, damage profiles generated from remote sensing coverage promise an accelerated rate of response, while guiding the scale of response efforts and resource allocation. They further provide critical information to international aid agencies, supporting logistical planning and deployment of equipment.

Environmental decisions regarding transportation Infrastructure activities are among the most difficult facing transportation decision makers. A myriad factors, laws, and regulations combine to complicate achieving timely consensus and effective decisions. Also, environmental assessment costs a lot of money and takes significant period of time. State DOTs are seeking transportation development decisions and operations that would provide maximum mobility while protecting important human and natural environmental resources. Nowadays, there are no rules per se as to how to conduct an environmental assessment using geospatial data. The particular objective of each assessment is dictated on case-by case based on what information and analyzes are required. In this paper, a framework for transportation infrastructure environmental assessment is presented. Remote sensing, image processing, data fusion modules, and GIS technologies will be utilized to develop a cohesive and integrated system to facilitate rational environmental decisions associated with transportation projects through cost-effective coordination of environmental information and data management. This will greatly enhance the ability of transportation agencies to be effective steward of the environment while carrying out its mission.

The objectives of this study are: (1) to investigate the spectral features of reflectance of productive inland and coastal waters in order to find spectral features which are closely related to phytoplankton density and chlorophyll concentration; and, (2) to devise and validate algorithms for chlorophyll estimation using reflectance data as the measured variables. We found that the information gained from the red (around 675 nm) and red edge (near 700 nm) spectral regions were sufficient for the construction of algorithms for phytoplankton density estimation. These algorithms were calibrated and validated in Lake Kinneret, and then applied to estimate chlorophyll concentration in numerous lakes and reservoirs with slight modification of the coefficients.

Some results are presented of satellite measurements of water circulation and chlorophyll concentration in several seas and lakes: Mediterranean Sea, Black Sea, Iowa Lake and Carter Lake (USA), Lake Kinneret (Israel) and Lake Issyk-Kul (Kyrgyzstan). Reflectance spectra of productive waters were measured in the range of 400 to 900 nm and analyzed to identify regions of the electromagnetic spectrum related to specific algal pigments. We explored the possibility of remote detection and quantification of chlorophyll-a and chlorophyll-b, relationship between chlorophyll concentrations and the commercial catch of fish (using Black Sea as an example). One of the objectives of this study was to review some aspects of relationship between water circulation and turbulence structure, and spatial distribution of algae and suspended sediments (using Lake Kinneret and Lake Issyk-Kul as examples).

The NCAR Community Atmosphere Model (CAM2) coupled with the Community Land Model (CLM2) shows a significant warm bias in surface air temperature over snow-covered areas in winter. An intercomparison of surface albedos from CAM2/CLM2 and MODIS reveals that in the northern mid-latitude grassland and cropland regions, the modeled values are much lower than observations mainly due to shallower-than observed snow depth. This underestimated snow depth is related to how snow cover fraction (SCF)is parameterized in the land module (CLM2). Most land surface models relate SCF to grid (or patch) averaged snow depth and surface roughness length. This study suggests that the SCF formulation of Yang et al. largely improves the simulations of snow depth, surface albedo and surface air temperature over non-forested regions in winter. However, snow ablation is delayed and a cold bias appears in spring, suggesting that the SCF-snow depth relationship may be different for accumulation and ablation, seasons. Guided by limited watershed-scale measurements, a different SCF-snow depth formulation for ablation season was tested in CLM2. Preliminary modeling results from CAM2/CLM2 indicated that using this SCF scheme for melting period and the SCF scheme of Yang et al. for accumulation period leads to the most encouraging results, such as a significant reduction of wintertime warm bias over snow-covered areas and few undesired effects on the springtime snow depth and air temperature. The caution of using these schemes will also be discussed.

With the advent of the Global Precipitation Measurement mission (GPM) in 2009, satellite rainfall measurements are expected to become globally available at space-time scales relevant for flood prediction of medium sized ungauged watersheds. For uncertainty assessment of such retrievals in flood prediction, error models need to be developed that can characterize the satellite's retrieval error structure. A full-scale assessment would require large number of Monte Carlo (MC) runs of the satellite error model realizations, each passed through a hydrologic model, in order to derive the probability distribution in runoff. However, for slow running hydrologic models this can be computationally expensive or prohibitive. In this study, Latin Hypercube Sampling (LHS) was implemented on a satellite rainfall error model to explore the degree of computational efficiency that could be achieved with a complex hydrologic model. For assessment of errors in time to peak, peak runoff, and runoff volume it was observed that LHS offered no significant benefit over the MC sampling method. However, for deriving the runoff simulation uncertainty at confidence limits greater than 90%, LHS was found highly efficient. With only a small fraction (in the order of 5%) of MC runs, LHS was able to produce the same 90% confidence limits in runoff simulation.

Considerable progress in continental hydrological research has been made recently that includes sub-grid-scale variability of precipitation, canopy interception, throughflow, and hill-slope runoff production. Many such studies have focused on one single process at a time. This work aims to examine the interplay between canopy interception, throughflow and runoff using the NCAR Community Atmosphere Model (CAM2) coupled with NCAR Community Land Model (CLM2). The simulations are compared with the observed runoff from the University of New Hampshire-Global Runoff Data Center (UNH-GRDC) 0.5 degree monthly climatological composite runoff fields. The simulations from the CAM2/CLM2 show an excessive canopy interception and low soil moisture content over the climatologically wet regions, especially in the Amazon basin. A series of experiments are conducted which explicitly account for the sub-grid-scale variability of precipitation and its effects on canopy interception and throughflow. These experiments incorporate changes in the treatment of topography-induced runoff. The results have demonstrated that the interception and runoff processes are intimately coupled, and that their schemes should be changed together to ensure the improvement in the hydrological simulations. The simplified topography-based runoff model (TOPMODEL) and the sub-grid interception scheme proposed in this study, when used together, result in better simulations of runoff. With these proposed schemes, the water budgets show favorable changes in the Amazon basin in that canopy evaporation is reduced, runoff is increased, and soil is wetter.

It is well recognized that there exists a need for accurate prediction of precipitation, whether it is for improvement of flood warning systems, water system management, or groundwater recharge assessment. Weather radar has enabled us to improve our quantitative observations of precipitation in the field of radar hydrology. However, radar-based estimates of rainfall accumulation and/or rate are subject to numerous uncertainties. Some errors may arise due to the inherent complexity of the mechanical and electronic system of detection while others may be due to the complexity of the terrain. As a result, the relation between measured radar reflectivity and surface rainfall is highly complex and can be influenced by many factors. Even though it has been the subject of many studies, no satisfactory method has been developed to date for accurately estimating rainfall when high spatial and temporal resolution is required. We propose to develop an approach to calibrate radar by applying a mathematical method originally proposed by Carasso et al. for image processing.

Uncertain environments stimulate development of innovative structures. Structures that can adapt to new environments and improve their performance over time have much potential for meeting new challenges. This paper reports on the construction of a unique active tensegrity structure containing five modules and ten actuators on telescopic bars in a closely coupled configuration. The control scenario under study is a constant slope requirement for quasi-static control. Behaviour is geometrically nonlinear and this is modelled using a combination of dynamic relaxation analysis with a neural-network based correction to account for effects such as joint friction. There is no direct solution for bar movements given required slope. Furthermore, the entire search space is very large. A standard engineering brut-force methodology of generate, analyse and test could take up to 10²² years to find a control solution. A stochastic search method reduces search time down to approximately one hour. Case based reasoning with stochastic search for case adaptation reduces search time further down to tens of seconds. Adding cases allows the structure to learn from its experience. An initial study of self diagnosis and self repair reveals that there is potential for demonstrating greater autonomy, thereby increasing the ability of the structure to accommodate uncertain environments.

The residual biaxial flexural strength of samples cored from shuttle orbiter windows impacted by hypervelocity micrometeorites was measured, and related to the depth of the impact crater. Results show that the current NASA prediction for hypervelocity impact (HVI) model is significantly conservative. This apparently is due to the fact that the assumed geometry of the critical defect geometry used in the model differs significantly from that of the actual defect ensemble associated with an HVI site.

Since the earliest flights of the Space Transportation System Orbiter, a slight "fogging" of the external window glass has been observed. The engineers responsible for the technical and operational aspects of the window system have commonly referred to this fogging of the glass as "haze". The haze had become a troubling technical aspect of the Orbiter window system since its cumulative (flight after flight) development was degrading the viewing properties through the window and distracting the flight crew from their immediate tasks. This paper will explain the history of the haze on the orbiter windows, describing what it is, what causes it, and how it is now being prevented. It will describe the early attempts to identify and source the problem, most of which came to incorrect conclusions. This paper will demonstrate how taking a fresh look at a problem without a preconceived idea of what the outcome should be allows a logical investigative methodology to correctly identify and characterize the problem and lead to the implementation of solutions to prevent the problem.

The use of tailored electromagnetic fields is considered to build solid-walled structures of specified geometry from random-shaped debris in Space. In previous work, a unified view had been established, linking experiments and theoretical results from optical, acoustic and long-wave electromagnetics to develop an expression for the acceleration per unit intensity on objects of given mass and size. The consideration was restricted to the Rayleigh scattering domain. This paper first uses the Rayleigh regime result to size the construction system for a 50m diameter, 2-meter thick cylindrical radiation shield at 1 A.U. from the Sun. Next, the implications are explored of exploiting Mie-regime interactions with beamed waves to refine the construction. Order-of magnitude gains are obtained in acceleration per unit intensity, with the application being to position individual construction blocks in refining the construction.

Results from plant growth experiments utilizing particulate growth media during space flight revealed difficulties associated with providing reliable and reproducible water and air supply to plant roots. These limitations have been attributed to insufficient understanding of liquid configuration and growth media transport processes in reduced gravity. This information gap has made it impossible to determine whether culturing technique or microgravity significantly effects water and air transport through particulate media in microgravity. The objective of this NASA-funded research program is the quantitative characterization of physical processes associated with flow of wetting and non-wetting phases in particulate plant growth media that are essential for successful design and control of plant production systems during space flight.

Modeling pore fluid distribution in porous media is an essential task in the exploration of plant growth under microgravity. The effects of vehicle vibrations (during launch and post-launch periods) and possible particle separation under zero gravity complicate the modeling of the distribution of water and air in plant growth chambers. In this paper, results from experimental investigations are reported on the distribution of immiscible fluid phases in soils and glass beads under the effects of vibrations. Hexadecane, a petroleum compound immiscible with and lighter than water, is used in the experiments. The higher freezing point of Hexadecane (18°C) allowed the solidification of the entrapped blobs in the presence of water in porous media, so that their size distribution can be obtained. van Genuchten's function, commonly used to express moisture retention curves, is found to be an adequate fit for the blob size distributions. It is concluded that the effect of vibrations is to break up blobs entrapped in porous media at residual saturation and reduce the mean blob size. The pore fluid distributions after vibrations are less uniform than those before vibrations.

Microgravity may indirectly cause plant stress by increasing boundary layers around plant organs (i.e. leaves and roots) because heat and mass transfer needed for normal metabolism are sustained by molecular diffusion through these boundary layers. Therefore, understanding, quantifying and controlling boundary layers is a crucial part of growing plants in space. Several experiments were conducted to quantify the effects of changes in boundary layers around plant organs using oxygen sensors, canopy temperature transducers, and anemometers. Oxygen consumption rates of wheat roots were determined at various depths of rooting media and the oxygen concentration at these depths was measured at various wind speeds. Generally, increasing wind speed above the roots slightly increased the oxygen concentration of the root zone, which suggests increased mass transfer of gasses at higher wind speeds. The boundary layer surrounding a plant canopy, quantified as aerodynamic resistance, was determined as a function of wind speed from energy balance measurements. Decreasing wind speeds below 0.5 m s^–1 significantly increased the canopy aerodynamic resistance. These studies provided baseline data for the design of a future KC-135 (parabolic) flight experiment. (Supported by NASA's Space Life Sciences Training Program and a grant from NASA's Office of Biological and Physical Research (OBPR) Fundamental Biology Program).

Plant growth in limited volumes of porous substrates is of interest for advanced life support systems for NASA's future space missions. Liquid behavior under microgravity introduces special considerations for selection of suitable porous plant growth media and the design of root modules for reliable water, air, and nutrient supply. It has recently become evident that the macroscopic dynamic behavior of the temporal and spatial under-saturation levels in root modules strongly depends on the physical behavior of the fluid at the microscopic (pore-scale) level. Ultimately, stability and break-up of liquid-bridges, -columns, and -films, confounded by, contact angle dynamics and hysteresis, phase discontinuities, capillary fingering and entrapment of the non-wetting phase together with dynamic rearrangement of solid particles and the complex geometry of porous media determine the saturation levels and its stability at macroscopic scales. However, it is not yet clear if and to what extent these micro-scale phenomena are gravity dependent. As a first step in studying liquid configurations in partially saturated angular pores we employed the Augmented Young-Laplace equation that simultaneously considers the contributions of capillary and adsorptive forces with a variable gravity term. Interfacial configurations in microgravity compared to gravity conditions for pores with various sizes and angularities. The difference between conditions for liquid held between parallel plates become significant only for pores larger than approximately 1 mm and for potentials very close to zero. Anecdotal evidence suggests that for Bond Number > 0.05 water flow under 1g becomes unstable (corresponding to flow in pores with radius > 0.6 mm. For smaller pores and for lower ambient matric potentials, the shape of liquid-gas interface at 1 and 0g are indistinguishable. Implications of liquid configurations on gas entrapment processes and on macroscopic retention and transport properties relevant to root module design are discussed.

An aerobic submerged membrane bioreactor was evaluated at Kennedy Space Center for possible use in lunar applications treating generated wastewater streams. The bioreactor contained an internal membrane (pore size = 0.2 μm), which allows for an infinite mean cell residence time (SRT) and also improved effluent quality. An analog waste stream simulating a the daily output of a 2-person crew was fed to the reactor continuously. The simulated waste stream contained a mixture of two surfactants and a urine analog. In previous studies at KSC, complete surfactant degradation was observed, however no nitrification (NH₄⁺ → NO₂^– and NO₃^–) was established. The goals of this study were to establish both surfactant and nitrifying bacterial populations. To promote the establishment of nitrifying populations, pH control and the addition of a nitrifying inoculm were implemented into the study. Results from the study show that 100 % surfactant disappearance was achieved in the reactor. Nitrification was also established during the study (180 day duration). Rates associated with nitrification varied dependent on set pH values, with 30% obtained at pH = 6.7 and 80% at pH = 7.5.

Agriculture in micro gravity is an important practical problem. Understanding the transport and distribution of water within soils is fundamental, yet classical methods don't provide information on all scales of interest. In this collaborative study, NMR imaging and relaxometry methods are being evaluated as tools for studying soil mechanics.

Liquid and gas exchange within a porous medium is likely to be altered in a microgravity environment. A difference in gravitational force can result in significant offsets in the water distribution in porous substrates such as plant growth media, due to the shift in hydrostatic force. The automated gas diffusion measurement systems being developed will examine the effects of variable gravity on water distribution and gas diffusion on Earth and on the International Space Station (ISS). The automated system will interface with the LADA control module currently on the ISS. To allow comparison of μg and 1g conditions, gas diffusion cell designs were horizontally oriented to minimize gravitational effects using a `thin rectangular profile' cell for 1g and a cylindrical cell design for flight. Electronic solenoid valves provide air and water flow control while pressure transducers measure water and substrate potential. Porous media water content is controlled using a porous membrane coupled with a metered pumping system. Diffusion measurements are made after purging two gas chambers separated by the porous medium with N₂ and with atmospheric air. Continuous measurements of oxygen in sealed dual-chamber diffusion cells provided concentration data for fitting diffusion coefficients where water content was controlled by imposing a low matric suction in the porous media (in the range of 0 to 30 cm). The system will be launched to the ISS on a Russian Progress vehicle in 2005.

The objective of this study was to evaluate the potential use of hollow fiber membrane-aerated bioreactors for the nitrification of wastewater during long-term space missions. To define the minimum acceptable treatment efficiency for the experiment, the water recovery system (WRS) at Texas Tech University (TTU) was used, which is a small-scale replica (1/20^th) of the WRS at NASA's Johnson Space Center (JSC). The WRS consists of a biological system designed for nitrogen and organic carbon removal, and a post-processing system consisting of reverse osmosis (RO), ion exchange (IE) and UV treatment. The biological portion of the WRS was the focus of this research and contains an anaerobic packed bed (PB) promoting denitrification, and a tubular reactor (TR) promoting nitrification. Biological systems have been deemed promising by NASA for long-term space applications because of their low mass and high energy efficiency. Both the biological portion of the WRS and the AMR utilized an internal recycle; this study analyzed the data from a recycle ratio (RR) of 1:10 (expressed as mL/min of feed to mL/min of recycled effluent). The AMR was operated at RR 10 for a period of 120 days, while the WRS was operated at RR10 for 109 days. The percent nitrification for the AMR (60.7%) was higher than the WRS (52.3%), indicating the possibility of the AMR as a replacement for the TR. During analysis of the two systems, it was noted that the AMR contained denitrifying organisms, supported by the removal of nitrogen and organic carbon (44.7% and 91.9%, respectively). The AMR was not originally designed to operate as a denitrifying reactor, but the data indicated the potential of the AMR operating as a combined carbon-nitrogen removal system. Following the analysis of this data, two more AMR's were built and are currently being evaluated at TTU.

Preliminary experiments for the Bio-Regenerative Environmental Air Treatment for Health (BREATHe) system have been conducted. The BREATHe system is part of a multicomponent life support system and is designed to treat contaminated liquid and gas waste streams simultaneously withing a closed life support system. Experiments focused on the BREATHe I system used for treatment of graywater and waste gas from a solids biological treatment process. In this first experimental phase, prototype benchtop reactors were constructed to evaluate surfactant removal. Surfactants, the major component of detergents, are the primary area of concern for graywater treatment. The recirculation rate was varied between 10 and 20 times the influent flow rate to determine the required recirculation rate for 90% COD removal from the influent wastestream. A recirculation rate of 20 times the inflow rate was required for 90% COD removal. Biological growth rate experiments were performed using two commercial laundry detergents (Tide and Cheer). Biological growth was observed in both cases and growth rates increased with increasing concentrations of Tide. Conversely, increases in Cheer concentrations resulted in lower biological growth rates, possibly due to toxicity.

A test was conducted to investigate the performance of a new type of gas trap for the International Space Station (ISS) Internal Thermal Control System (ITCS). The new gas trap holds entrained bubbles and allows them to dissolve into the flowstream. A test was performed using a prototypic gas trap to investigate the dissolution rate of trapped air bubbles. The test results are compared to the available theory, and a recommendation for the most accurate dissolution rate prediction is made.

Separate cation and anion ion exchange (IX), coupled with vacuum-assisted or gas-sweep desorbtion of dissolved carbon dioxide gas, is routinely utilized in terrestrial applications to increase IX bed life by reducing inorganic carbon loading. Successful application of this mature industrial process to spacecraft wastewater processing has the potential to significantly reduce IX bed volume when compared to current mixed-media IX beds. However, potential complications that could offset these benefits include production of free gas and low pH downstream of the cation exchange bed. The purpose of this work was to: (1) Determine the magnitude of these complications, (2) Measure the inorganic contaminant removal effectiveness of Amberjet UP1400 Strong Acid Cation (SAC) and UP4000 Strong Base Anion (SBA) exchange resins, and (3) Quantify the carbon dioxide removal effectiveness of a commercial off-the-shelf membrane contactor (MC) using vacuum-assist. Test results showed: (1) Amberjet UP1400 Strong Acid Cation (SAC) and UP4000 Strong Base Anion (SBA) ion exchange (IX) resins effectively removed all measured inorganic contaminants prior to bed breakthrough, (2) the configuration of a cation IX (CIX) bed followed by a membrane contactor (MC) for vacuum desorption of carbon dioxide removed an average of 91% of the inorganic carbon from the process stream, and (3) there was no measurable adverse effect on the materials of construction. These results indicate that the imposed design challenges are minimal, and that this process can be incorporated into spacecraft wastewater processing applications.

Using titanium dioxide (TiO₂) to photocatalytically degrade persistent and hazardous organic contaminants present in aqueous waste streams has been extensively examined and utilized for many applications. Typically these organic contaminants contain aromatic and/or halogenated functional groups. Their oxidative destruction to CO₂ or smaller polar organic molecules that are readily biodegradable, such as alcohols and ketones, is usually considered an effective treatment. However, in considering the use of TiO₂ photocatalytic degradation to treat water intended for human consumption, the reaction products and photodegradation kinetics of small polar organic compounds must be carefully considered. Such compounds are highly soluble and do not adsorb strongly to the TiO₂ surface and so they may therefore be fairly resistant to photodegradation. In this study, preliminary experiments examined the photodegradation of isopropanol, and its photodegradation product acetone, as a function of pH and with several different TiO₂ substrates, with the eventual goal of providing a suitable photocatalyst for the final processing step in NASA's Water Recovery System (WRS). Isopropanol and acetone were selected as test compounds since they were detected at several processing points in the NASA WRS. In the absence of TiO₂, using a 450 watt mercury lamp, direct photolysis of isopropanol (100 ppm) resulted in insignificant degradation over 3 hrs. However, in the presence of 2g/L TiO₂ at natural pH, isopropanol completely disappeared within 3 hrs, resulting in the nearly complete transformation into acetone. Subsequent photodegradation of acetone occurred at a much slower rate and was completely mineralized in approximately 8 hrs. Increasing the pH slightly decreased the photodegradation rate of isopropanol and lead to 25 ppm of acetone remained undegraded during the reaction period. This suggests that ^•OH radicals are being scavenged by carbonate ions that are produced by acetone mineralization. Conversely, the degradation rate of isopropanol and acetone was enhanced slightly by increasing the ionic strength. The presence of tetranitromethane decreased the isopropanol degradation significantly from 85 to 59% over 75 min. This result, combined with the minimal degree of adsorption of isopropanol and acetone onto the surface of the photocatalyst, suggests that the photodegradation pathway occur via free ^•OH radicals in bulk solution rather than on the catalyst surface.

Granular hard bed materials like activated alumina and magchem packed in cylindrical containers are used for removing volatile organic components from wastewater aboard the International Space Station. For proper packing in the microgravity environment and to keep the bed material in place, a spring mechanism is used at one end of the bed. Spring force is a critical factor in providing appropriate compaction to the entire length of the bed media throughout the course of operation. This paper presents results from an experimental study of a full-scale, 38.1 cm (15 inches) long and 3.7 cm (1.44 inches) diameter, activated alumina bed enclosed in a cylinder to determine its force-displacement (loading-unloading) behavior, friction mobilizing force, and normal stress distribution under various axial loads and levels of packing. It is observed that force-displacement behavior becomes more linear with decrease in void ratio (increase in compaction) of the bed media. Friction mobilizing force between the bed media and the wall of the encasing cylinder is found to be significant. Axial normal stress distribution along the length of the bed media is determined using a load sensor. It is seen that the axial stress decreased exponentially with increase in depth from the loading end of the granular media.

Limited numbers of experimental units are a pervasive constraint on experiments both in microgravity and for many ground-based experiments analogous to microgravity. An experiment to compare two methods of measuring hydraulic conductivity (K) in particulate plant growth media serves as a case study for experimental design and analysis for limited resources. This case study explores balanced, optimal cross-over designs, repeated measurements, orthogonal polynomials, imputation of missing data, assessment of distributional assumptions, and tests of equivalence.

We investigate the aerodynamic forces and moments exerted upon axisymmetric bodies rotating about their symmetry axis in a free-molecular flow. The velocity field consists of a mean flow at arbitrary orientation relative to the body superimposed upon a random thermal motion described by the Maxwell-Boltzman velocity distribution. The gas-surface interaction model is based upon a combination of specular and diffuse reflections as characterized by normal and tangential momentum accommodation coefficients. For the general case, expressions for the aerodynamic disturbances are given in the form of surface integrals. Analytical and numerical results are presented for the case of a spinning sphere.

Wind engineering formally emerged in the late 1960's, after Davenport developed analytical methods of modeling wind for loading applications, and Cermak developed means of modeling it physically in boundary-layer wind tunnels. Although this would lead eventually to solving problems as diverse as dispersion of atmospheric pollutants, ventilation of buildings, pedestrian comfort in urban environments, and distribution of snowdrifts around buildings and roadways, it was primarily developed as a tool for studying wind loads on tall buildings. Much of this development took place at Colorado State University (CSU), and later at Cermak Peterka Petersen, Inc. (CPP), in studying the dynamic response of launch vehicles to ground-wind loading. This paper describes the development of wind-tunnel tools for this purpose through case studies on a number of those projects.

Structural Health Monitoring (SHM) systems increase aerospace vehicle safety and reliability, while reducing vehicle operating and maintenance costs. While many advances have been made in terms of sensors, composite materials, and damage detection algorithms, much additional research needs to be focused on probabilistic modeling, probabilistic analysis and design, as well as on sensor placement optimization under uncertainty. This paper develops a methodology to integrate the advances in various individual disciplines for optimum design and layout of structural health monitoring systems under uncertainty.

The presence of rare metallurgical or manufacturing anomalies in aircraft turbine rotors/disks may contribute to uncontained engine failures. A probabilistic methodology has been developed to quantify the risk of fracture and the influence of periodic inspection on overall risk, supplementing the current safe life approach. This paper summarizes the methodology and computational implementation, including a brief description of a new method for defining surface damage-related crack growth using 3D finite element results. The results can be applied to risk assessment of aerospace structures where uncertainties associated with fatigue crack growth must be quantitatively addressed.

NASA witnessed several instances of damage to the forward skirt of the solid rocket booster (SRB) during splashdown in the Atlantic Ocean following shuttle launches in the 1990s. A reliability analysis of the splashdown sequence is conducted in this paper to provide insight into the random nature of the splashdown damage issue. Using the Dytran finite element model software, a rigid body model of the SRB is combined with a high-resolution stress model to predict the stresses produced in the forward skirt as a result of splashdown. A response surface is constructed to allow for a probabilistic analysis to be conducted. Random variables considered include the vertical and horizontal velocity of the SRB at impact, as well as the axial orientation of the SRB during rollover.

This paper presents a probabilistic optimization methodology for aerospace vehicle design under uncertainty. The inclusion of linkages between system-level and component-level design requirements leads to multidisciplinary optimization (MDO). The proposed methodology formulates and solves a probabilistic multidisciplinary optimization problem for the coupled design of a reusable launch vehicle (RLV) geometry and its liquid hydrogen fuel tank.

This paper describes the analysis of a 16-blade impeller geometry to investigate its response to structural mistuning including the impact on high cycle fatigue life. The analysis was performed using the ANSYS to determine the tuned structural response and REDUCE/TurboREDUCE to investigate the impact of structural mistuning on blade vibratory response for a rotor disc. The results to date showed a significant increase in response amplitude because of frequency mistuning of the impeller. A Cumulative Distribution Function and a Probability Density Function have been developed for a selected mistuning level.

This study presents the derivation and solution of nonlinear dynamic equations of a lamated composite plate under blast load. The plate has a rectangular planform and has clamped boundary conditions on its edges. The equations of plate motion are based on the von Karman large deflection theory of thin plates and are derived from the virtual work principle. An aproximate solution is assumed for the space domain and then the Galerkin Method is used to obtain the nonlinear differential equations in the time domain. The finite difference method is applied to solve the system of coupled nonlinear equations. The results of theoretical analysis are compared with the experimental results. A good agreement is found for the peak values and frequencies.

A 2.5 m long horizontal axis wind turbine rotor blade, which had been designed before, was redesigned and analyzed using different composite structures. The blade was linearly tapered and bi-linearly twisted. The different composite layout schedules that include foam core sandwich and laminated sandwich were performed to lower the weight and stiffen the structure with special consideration given to the minimization of manufacturing complexity and cost. Strain results and natural frequencies of the blade were obtained using finite element analysis by commercial FEM software HyperMesh, ABAQUS and ANSYS. It was seen that using laminated sandwich structures formed with fiberglass and foam core has benefits in minimizing the blade weight.

The structural performance of compressor composite blades of advanced engine concepts is assessed in the presence of uncertainties in the leading edge pressure, fabrication process variables, and material properties. The probabilistic evaluation is performed through the NASA Engine Structures Technology Benefit Estimator computer code [EST/BEST]. EST/BEST software system is multi-factor, multi-scale, and multi-disciplinary software system to analyze the engine structures. The effect of scatter in the primitive variables on the durability of the blade is quantified. The probabilistic analysis indicates that the high reliability fracture rotor speed is about 2.5 times the design speed. The results from the sensitivity analysis indicated that leading edge pressure uncertainty has significant effect on structural durability. The computational methodology that is presented in this paper is generic and can be applied to perform reliability and risk assessment of other types of structures.

An analytical model is presented to predict the nonlinear response of a double wall sandwich cylindrical shell system subjected to random excitation. Nonlinear spring-dashpot models are integrated into the system to characterize the behavior of the soft core, Donnell's thin shell theory is used to develop the governing nonlinear equations of motion. A Monte Carlo simulation of stationary random processes, multi-mode Galerkin-like approach, and numerical integration procedures are used to develop linear and nonlinear response solutions of simply-supported cylindrical shells. Numerical results include time domain response histories, root mean square values and response spectral densities.

Use of concrete-filled fiber-reinforced polymers (FRP) tubes (CFFT) for columns and piles has been studied extensively over the last decade. The focus, however, has been exclusively on the short-term monotonic or static behavior of such hybrid systems. The present study reviews the low and high cycle fatigue of CFFT members. A number of test parameters were considered as follows: characteristics of the FRP tube in terms of thickness and lay-up, type and level of cyclic loading, end restraints, and presence of internal steel reinforcement. The study compares the fatigue life as well as energy dissipation of the CFFT with conventional structural columns and piles. Test results revealed that fatigue behavior of CFFT is primarily dominated by the behavior of FRP. Matrix composition and fiber architecture have a greater effect on the fatigue life and performance of CFFT. Significant stiffness reduction was observed irrespective of the type of laminate considered in the present investigation. The study indicates that, with proper design of the FRP laminate architecture and even without any internal steel reinforcement, it is likely to achieve superior fatigue performance than their reinforced concrete counterparts. In addition, it is also possible to develop adequate ductility and dissipate considerable energy in CFFT members at levels quite comparable to their reinforced concrete companions.

Dynamic large deflection analysis of composite plates is considered. Galerkin method with the use of Newmark's scheme in association with Newton-Raphson method is applied to obtain the dynamic nonlinear response of the plates. The von Kámán plate theory is utilized and the governing differential equations are solved by choosing suitable polynomials as trial functions to approximate the plate displacement functions. The solutions are compared to that of finite strips. A very close agreement has been observed with this approximating method. In the solution process, analytical computation has been done wherever it is possible, and analytical-numerical type approach has been made for all problems.

In this study, the dynamic response of a laminated beam is investigated experimentally and numerically. The beam was constructed using a balsa core and glass/epoxy facings. The boundary conditions are fixed at the one end and free at the other end. The tests were performed dropping a spherical mass on the free end of the beam. The dynamic strains were measured at two points on the beam. The beam was also modelled using the finite element method. The Ansys/LSDyna was used for modelling and the analysis of the laminated beam. The experimental and numerical results are compared for the peak strain and frequency.

Among the time integration methods used in solid mechanics, Newmark family of algorithms (along with Galerkin finite element) has been most popular and gathered much attention over the years. Recently, time discontinuous Galerkin method (TDG) and discontinuous Galerkin method (DGM) are being investigated by the researchers due to their advantages in wave propagation. In this study TDG and DGM are combined to have space-time discontinuous Galerkin formulation.

WJM (Weigh-In-Motion) system is an important part in the traffic data collection and law enforcement. A WIM system based on multiple piezoelectric sensors has been built to acquire data of axle weight from a moving vehicle. In order to design a good WIM system, different kinds of WIM systems will be compared in this article. Algorithms have been developed to interpret the acquired data and compute the axle weight, then to estimate the gross weight of the vehicle. A model of piezoelectric sensor was used to simulate the performance for WIM system that was also applied for the design of the charge amplifier. Comparison between Peak and Area Integral Algorithms has been made. The new speed correction algorithm conducts the measurement more accurately. The multiple sensors based design improves the measurement accuracy by reducing the effect of the vehicle dynamics.

A review is presented for vibration suppression of smart civil structures with piezoelectric control actuation. Piezoceramics have been known as low-cost, lightweight, and easy-to-implement materials for active control of structural vibration. This paper first presents basics about piezoceramic materials, various actuation methods and types of piezoceramic actuators. Then this paper reviews researches in application of piezoceramic actuators in various civil structures such as beams, steel frames, trusses, and stay-cable bridges. This paper concludes with future trends in active vibration control using smart materials.

This paper discusses of the monitoring of the temperature distribution by an optical fiber Bragg grating sensor system. The sensors are embedded in a pipe underground. Ground-source heat pump system utilizes the thermal energy of the underground soil to heat or cool a building. Optical fiber Bragg grating sensors are used to measure the temperature distribution of the soil and the thermal difference of the circulating water system. The sensors were designed and packaged delicately to eliminate the influence of strain as well as to improve the thermal sensitivity. Three Bragg grating sensors were placed at intervals of five meters in a deep well with a length of 25 meters. Data were collected prior to the installation of the monitoring system and immediately after the installation of the water pipes using a commercial FBG interrogation system. The ultimate purposes of these tests are to measure the water temperature fluctuation along the pipe at the places where the sensors were installed during the operation of the ground source heat pump system, and evaluate the reliability of FBG sensor system for a long period.

Shape memory alloy (SMA) is a novel functional material and has found increasing applications in a variety of areas. Recently, research efforts have been extended to using SMA-based devices for smart civil structures. This paper presents a review of application of the SMA materials for both passive and active vibration controls of civil structures. First, an overview of the characteristics of SMA is presented. The shape memory effect (SME) and pseudoelasticity, two major properties of SMA associated with the thermal-induced or stress-induced reversible hysteretic phase transformation between austenite and martensite, are reviewed. Those unique properties enable SMA to be used as actuators, passive energy dissipaters and dampers for vibration control of civil structures. This paper then reviews current researches using SMA-based devices or members for vibration control of civil structures with representative examples. For passive vibration control, the pseudoelastic SMA is used to increase the structural damping and dissipate energy. In the literature, the structure isolation and energy dissipation systems with the SMA material are two main systems for passive vibration control purpose. The operation mechanism, design and experimental results of several developed vibration control systems with passive or active SMA-based devices are presented in the paper. This paper concludes with a comparison of SMA-based damping devices with others and future trend of SMA applications in civil structures.

The space environment has deleterious effects on materials. The mechanisms for such degradation (and possible enhancement of properties) are well known. Yet, experimental data on this subject is few and inconclusive. While space flight experiments have generated data for Low Earth Orbit flights, no space experiment has flown in Medium Earth Orbit. Hence, the prediction of material behavior has to be inferred from known mathematical models of space weather and ground based radiation data. This paper will present an overview of literature on this subject to draw some conclusions on the possible changes in the mechanical response of fiber reinforced polymer composites.

The introduction of micro-satellites has revolutionized the space missions. The mass of this small satellite is very critical to the mission. Any weight savings will benefit significantly towards the orbital lifetime or revenue-producing life of a communications satellite. One of the weight saving schemes is by using the solid propulsion fuel as load bearing material (structural components of the spacecraft). An experimental investigation was conducted on the elastic modulus of the Pulsed Plasma Thruster (PPT) fuel with various reinforcements. The PPT is used for guidance, navigation, and control in these satellites. PPT uses solid Teflon propellant. However, Teflon cannot be used alone since the material is very soft. Reinforcing the fuel with high modulus fibers will enhance the structural performance of the fuel. Therefore, an experimental program was carried out to study the structural properties of the reinforced fuel. In this paper, the result of the reinforced fuel with different materials will be presented. Different fabric contents were also investigated.

100% of the ISS windows are manufactured from glass. As a structural material, glass is a poor choice for use in pressure vessels when failure will result in the loss of life. Structural use of glass has several difficulties. First, glass is a brittle material and fails without indication of imminent overload. Additionally, minor flaws in the surface of glass can have significant impacts on the structural integrity (ultimate strength) of material. Finally, glass is susceptible static fatigue. This material property causes the loss of ultimate strength in the material over time when the glass is under load. The windows on the ISS are exposed to a hostile environment that includes bombardment from tiny micrometeoroids that damage the material surface. Additionally, since the material is employed as part of the pressure shell, it will be constantly loaded with one atmosphere of pressure for the 15 year life. With each of the unique material problems associated with glass, how does NASA ensure the structural integrity of the ISS windows? This paper describes how NASA technically mitigates the risks associated with engineering using this difficult material.

It is common that infrastructure facilities, especially those exposed to challenging environments, undergo premature deterioration. Although reinforced concrete structures are cost-efficient and generally durable, severe costs can be incurred by owners when these structures are exposed to aggressive corrosive environments, reducing the service life of the structure. Because corrosion of the steel reinforcement is a major cause of deterioration of reinforced concrete structures, engineers and designers are investigating various methods to improve the corrosion resistance performance of these structures. This paper focuses on investigating the performance of concrete structures reinforced with non-metallic reinforcing bars, specifically glass fiber-reinforced polymer (GFRP) reinforcing bars.

This paper describes an engineering process from analysis/design to construction for a high performance CFRP/GFRP composite trimaran. The objective of this project is to demonstrate that good engineering practice will overcome some of the limitations in the composite structural system such as stiffness, connections, and anisotropic material characteristics. The practical example presented in this paper involves a CFRP/GFRP vessel that must be light-weight, operated in a highly corrosive environment, and under a simultaneous wind load and hydrostatic pressure. The structural system is constantly subjected to a combination of torsion, bending, and axial loading conditions. The composite vessel is used as a racing sail boat and has established several record breaking speed and sailing times in the national and international competition. A uniquely designed vessel with tri-hull system will be presented in conjunction with design process, material selection, and construction method for the hybrid composite system. In addition, the technology transfer and historic experience from aerospace composite structures to civil composites will also be discussed, and a summary on how to avoid composite structural failure, and how to develop a safe and sound composite system will be concluded at the end of paper. The objective of this paper is to give the practicing engineer confidence in the use of polymer composite materials and to help overcome some of the bad publicity on the use of these materials.

The significant attention devoted to rehabilitation of civil infrastructure has presented a unique opportunity for development of combined fiber-reinforced plastic (FRP) and concrete materials, which can provide longer service-life and lower life- cycle costs than conventional materials. However, there is a concern with the long- term reliable performance and durability of the FRP-concrete interface bond, which is critical to the application of this technology. In this study, a work-of-fracture method using three-point bend beam (3PBB) specimen is adapted to evaluate the mode-I fracture and durability of FRP-concrete bonded interfaces. The effects of freeze-thaw and wet-dry cycles on the mode-I fracture of FRP-concrete bonded interfaces were studied, and the test results indicated that the fracture energy under freeze-thaw and wet-dry cycles both decreased as the number of cycles increased. The examination of interface fractured surfaces along the bond lines under various freeze-thaw and wet-dry cycles revealed that a transformation of failure mode occurred, from the cohesive fracture of concrete under no environmental exposure to adhesive interface failure at high cyclic conditioning. The deterioration of FRP- concrete interface under freeze-thaw and wet-dry cycles was founded relatively pronounced.

This study concerns the interfacial bond strength between FRP rebar and normal strength concrete (NSC). Three different types of rebars were tested using the beam specimens: carbon (CFRP); glass (GFRP), and steel. This involved a total of 26 beam specimens containing 10-, 16-, and 19-mm rebars. The test embedment lengths were 10, 15 and 20 times the rebar diameter (d_b). For each rebar tested, the results concern load deflection curves, bond stress-slip constitutive relationships and the mode of failure. For evaluation purposes, the test results from a previous study on pullout specimens by the authors are also included. Based on these results, a proposal for the average bond strength of straight FRP rebars under tension in NSC is made.

Due to increased traffic volumes and damaged bridge structures, there is a pressing need to develop a collision protection system for highway bridges against over-height truck impact. In this study, a linear elastic model for impact response of bottom face sheet-rigidly supported sandwich structures including shear-off effect is developed. The solutions of discrete model, concentrated and distributed loading cases for collision protection I-Lam system are obtained, of which the contact force history and maximum deflection are predicted. Compared to the LS-DYNA finite element analysis (FEA), the proposed analytical methods show their accuracy and simplicity in predicting the impact response. The discrete model shows a better correlation with FEA predictions; while the model with distributed forces overestimates the deflection of the top face sheet but under-evaluates the peak contact force. The relatively simple and accurate models developed can be used to approximate the impact response of rigidly supported sandwich structures.

Honeycomb Fiber-Reinforced Polymer (HFRP) sandwich panels with sinusoidal core geometry have shown to be successful both for new construction and rehabilitation of existing bridge decks. This study is concerned with the behavior of HFRP panels under out-of-plane shear considering skin effect. Two factors are addressed that contribute to the skin effect: shear warping and bending warping. Shear warping corresponds to assumed hinge connection between facesheet and core, and when warping is also considered, it corresponds to a rigid connection. A closed-form solution, based on proper description of displacement field at the interface, is derived considering shear warping. The accuracy of this method is verified by Finite Element (FE) results. The FE model is then applied to study bending warping effect. The stiffness and the stress distribution subject to skin effect are presented. Suggestions for future design considerations are given.

A composite material model has been developed in LS-DYNA as a user defined material model (UMAT) to characterize the nonlinear strain rate dependent behavior of a unidirectional polymer matrix composite under an arbitrary state of stress or strain. The composite model is implemented as a homogenized lamina based on micromechanical level analyses and is designed for shell elements in order to ensure computational efficiency. By defining the orientation and thickness of each through- thickness integration point of the shell, the UMAT model can be used to represent laminates of various fiber orientations and even textile composites. Experimental and numerical stress-strain curves are compared for a representative polymer matrix composite, with the numerical model predicting the experimental response reasonably well. Progressive damage models of different application strategy are discussed.

Based on the first-order shear deformable plate theory, an improved approach for fracture analysis of a crack at the interface of a bi-layer structure is developed to calculate the energy release rate and stress intensity factor. By modeling the uncracked region of the structure as two separate Reissner-Mindlin plates bonded perfectly along the interface, the present solution is able not only to take into account the shear deformation in the cracked region, but also to capture the shear deformation in the uncracked region of the structure. A closed form solution of energy release rate and mode decomposition at the interface crack is obtained for a general loading condition, and it indicates that the energy release rate and stress intensity factor are determined by two independent loading parameters. Compared to the approach based on the classical plate theory, the proposed method provides a more accurate prediction of energy release rate as well as mode decomposition. The improved solution developed can be effectively used to predict crack growth along the layered structures.

Many composite materials and structures are susceptible to defects, which may grow to failure of the structures. To avoid the catastrophic failure of structures, development of a reliable method of structural health monitoring is important in maintaining the integrity of the structures. Dynamic response-based damage detection offers a simple procedure as an alternative to the conventional nondestructive evaluation techniques. In this paper, experimental aspects of dynamic response-based damage detection technique on carbon/epoxy composites are addressed. Smart piezoelectric materials are used as sensors or actuators, and they are surface-bonded to the beams and used to acquire the curvature modes of the structures. Four types of damage detection algorithms are evaluated for several possible damage configurations. The quality of damage identification with different detection algorithms is discussed. The developed experimental damage identification technique using curvature modes and piezoelectric materials can be effectively used in damage detection and health monitoring of composite structures.

There is increasing interest in reducing the cost of maintenance and rehabilitation of civil infrastructure by using self-monitoring materials as part or total component in structures. Structure repair and rehabilitation are expensive and time-consuming processes, especially when damage is not discovered before crakes and deformations affect the integrity of the structures. On the other hand, methods used for regular structure health inspection again add to its service costs. Hence, there is interest in developing smart (self-monitoring) materials that provide the structural capability and responding to applied stresses and other flaws. In this study, the use of conductive filler in polymer composites was investigated to develop smart materials. The volumetric electrical resistivity was found to be stress/strain dependent (piezoresistive). The composite systems were optimized and the electromechanical responses were quantified.

In this overview of micropumps actuated by smart materials, we outline different smart materials actuating mechanisms and their fabrication, theoretical analyses and simulations. Suggestions are made for designs and future trends of micropumps actuated by smart materials.

The paper proposes a Linear Parameter Varying (LPV) approach to control nonlinear systems with hysteresis. An equivalent representation of the hysteretic system as a LPV system is proposed. The design approach is demonstrated using a two-mass-spring system with a hysteretic spring force. The LPV controller is scheduled based on real-time measurements of the spring stiffness. The results are compared to a robustH_∞ control design. It is shown that the LPV design provides superior performance and avoids the conservatism of the robust H_∞ design. Thus, LPV gain-scheduling is an effective approach to control hysteretic systems.

There are strong demands for health-monitoring techniques in civil engineering. Piezoelectric sensors and actuators provide a new promising approach to addressing these demands. Smart structure embedded with piezoelectric sensors and actuators has the advantage of structural simplicity, low cost, quick response and high reliability. This paper first reviews the basics of the piezoelectric materials, in particular the Lead Zirconate Titanate (PZT), and then presents various methods of structural health monitoring using piezoelectric materials. The most popular principle of health monitoring using PZT patches is to compare the dynamic response, impedance or modal parameters of the current structural status with those of the healthy state. In the implementation of this principle, the health monitoring methods using piezoelectric materials can be summed up as comparing the following parameters between the healthy structure and the damaged structure: modal parameters (modal shape, natural modal frequency, damping ratio, etc.), frequency response, time response, impedance response, transfer function, etc. In processing and analyzing the sensor signal, the artificial neural network, wavelet analysis etc. are useful to detect the nature, size and location of damage.

Perforating thin-walled steel studs in steel framed housing is an effective method of reducing heat loss and improving energy efficiency. Steel studs with perforation for energy efficiency are called thermal studs. This paper presents an experimental and numerical investigation of the thermal performance of lipped thermal studs in fire. Four tests were carried out in the fire-testing laboratory of the University of Manchester, Isowool 1000 was used as internal insulation in all tests. Gypsum boards were attached to both sides of the test sections. All tests were conducted under the standard fire condition and lasted for 2 hours. These test results were compared with those of an existing test using solid steel section. Test results show that perforation had significant influences on temperature distributions in thin-walled steel sections. Even with a very small perforation size. there is a large temperature difference across each perforation. Overall, the temperature difference between the exposed and unexposed sides for a perforated section is much greater than for a solid section, under the same fire condition. These tests were simulated using a general finite element package ABAQUS. The purposes of these numerical simulations are to check the capability of ABAQUS in simulating complex temperature fields, to select appropriate simulation strategy and to determine appropriate material properties.

An algorithm for optimizing the allowed drilling domain with allowance for the errors of measuring instruments has been developed to allow more reliable control of the positioning of Marine Floating Platforms. Minimum risk is used as the optimization criterion and the optimal limits of the feasible drilling area are found for different positioning systems.

Two approaches that should be important in designing space structures are discussed: active design in contrast to passive design, and consideration of nonlinear effects in contrast to being limited by linearity. It is stressed that use of these approaches will result in safer and lighter structures.

In the paper, the Poynting-Thomson (P-T) model and the Kelvin Hooke (K-H) model are, respectively, applied to the unsupported region and the supported region of the soft rock tunnel By utilizing Laplace transform and inverse Laplace transform, the stress expressions in the supported region and the unsupported region are obtained, respectively. Expanding the expression of displacement in the supported region into a Maclaurin series, and utilizing the accumulative displacement around rock obtained through observation, a theoretical model is set up. The model and its solution for rheology problem of anchor-grouting soft rock tunnel in the paper have been proved to be effective in the practical engineering.

This paper describes progress on the construction of the United States Antarctic Program's Modernized South Pole Station, managed by the National Science Foundation (NSF). This project, formally known as South Pole Safety and Environmental/Station Modernization (SPSE/SM), has entered the seventh year of a ten-year construction schedule, with a planned 2007 completion date. This paper addresses elements of the design, budget, logistics, construction schedule, resolution of construction and design conflicts, and construction progress to date.

The Ocean Technology Foundation (OTF), in conjunction with the University of Connecticut, has developed over the past eight years the concept of an outer continental shelf ecosystem study program termed OASIS (Ocean — Atmosphere — Seafloor Integration Study). The physical facility from which this study would be conducted is termed Ocean Base. Ocean Base One (OB1) will be a prototype/proof-of-concept national network of ocean bases that is proposed by OTF. OB1 will be an oil production type platform with a one-atmosphere observation habitat within it's structure at a depth of 61 meters (200 ft.) and a one- atmosphere/ambient pressure diver and submersible lock-out habitat attached to it's base at a depth of 165 meters (540 ft.). A bottom habitat design concept is envisioned for OB1. It will be positioned 80 nautical miles south of Nantucket Island (southern New England) at the head of Veatch Submarine Canyon.

Cambodia is now undergoing rapid urbanization, after decades of impeded progress due to the 1970–79 civil war and the subsequent socio-political instability. The rapid urbanization has led to chaos within the infrastructure systems, making them inadequate in responding to the challenging natural climate and in creating hospitable urban habitats for the people. The goal of this paper is to assess the infrastructure conditions in Cambodia in the context of its urbanization. The study will concentrate on informal settlements, whose explosive growth is a direct manifestation of rapid urbanization. It will focus on water infrastructure as one of the prime sectors responsible for the social, economic, and environmental security of the region. The study will also discuss ways in which the habitability of these informal settlements can be improved. Implementations of intermediate technologies that have been developed and supported with local means will be presented as case studies.

As the National Science Foundation's Arctic Logistics Contractor, VECO Polar Resources (VPR) has completed engineering, construction, and operations projects in environments ranging from the tundra of Alaska's North Slope to the summit of the Greenland Ice Cap. They have ranged from providing power and communications for remote instrumentation to building, maintaining, and operating 45-person field camps. The remoteness and extreme conditions found in these diverse terrains have offered a set of common challenges to the VPR team. The varied and extreme physical environments of the Arctic ensure that each project undertaken by VPR is unique. Tundra, permafrost, snow, ice all provide different engineering and construction challenges. A variety of extreme weather conditions require careful selection of materials for reliability and maintainability. High latitudes limit the length of construction seasons and accessibility to sites. Recruiting and retaining a quality workforce willing to work under such conditions can also be difficult. We will discuss how to strike a balance between meeting all of the unique requirements posed by the physical environment of the Arctic and maintaining an efficient and cost effective operation that meets the needs of our customer. The remoteness of many of VPR's field sites poses another set of challenges. Materials and equipment must often be transported to the sites via small aircraft. Communications and power infrastructure are typically nonexistent. Remoteness also contributes to staff recruiting/retention issues. We will address how to effectively undertake construction and operations in remote sites where little or no infrastructure is available. Field sites built and operated by VPR are the platforms for cutting edge scientific research, much of it environmental. Therefore we must operate with minimal impact on the fragile environment of the Arctic. We will discuss strategies we are pursuing for reducing emissions, incorporating concepts of sustainable design, and for delivering our products and services while remaining good environmental stewards.

NEEMO is the NASA Extreme Environment Mission Operations, a cooperative project between NASA and the National Oceanic and Atmospheric Administration (NOAA). NEEMO was created and is managed by the Mission Operations Directorate at the Johnson Space Center in Houston, Texas. On the NOAA side, the National Undersea Research Center (NURC) in Key Largo, FL, with the help of the University of North Carolina at Wilmington, manages and operates the Aquarius Program. NEEMO was developed by astronaut training specialists to utilize an undersea research habitat, as a multi-objective mission analog for long-duration space flight. Each mission was designed to expose astronauts to extreme environments for training purposes and to research crew behavior, habitability, and space analog life sciences. All of this was done much in the model of a space mission utilizing specific crew procedures, mission rules and timelines. Objectives of the missions were very diverse and contained many of the typical space mission type activities such as EVAs (also known as extra vehicular activities), in-habitat science and research, and educational, public outreach, and media events. Five missions, dubbed NEEMO 1–5, were conducted between October 2001 and July 2003, the longest of which (NEEMO 5) lasted 14 days.

The 9-meter full motion antenna developed by VertexRSI was installed at the South Pole in 2001 as part of the National Science Foundation's (NSF) Amundsen Scott Pole Station. The maximum wind specification for this antenna is 80 mph, and the worst case temperature is –110° F (–79° C) The antenna structure consists of two major components: The reflector and the pedestal. The reflector is the parabolic dish and is 9 meters in diameter. The pedestal is the structure that the reflector is mounted on. The structure also consists of a steel platform assembly and structural connections. Extreme cold temperatures required special considerations with regards to material selection. Appropriate materials that address cold temperature and brittle fracture concerns were selected carefully to account for the extreme weather conditions that the 9-meter antenna experiences at the South Pole. Structural integrity, cost, time, and workability were used to develop a final design. Stress levels in all components are kept within allowable stress limits specified by the American Institute of Steel Construction (AISC) Manual of Steel Construction, Allowable Stress Design for steel components and the Aluminum Design Manual for aluminum components. Since stress levels influence the likelihood of brittle failure, further improvements in structural integrity were implemented by increasing the margin over allowable stress requirements to 2 in steel components where possible.

Large areas of the artic landscape consist of tundra with deep deposits of highly compressible organic soil (peat), which makes construction of roads and structures very challenging and expensive. To design engineering works founded on peat, engineers must find mathematical models, used with measured soil parameters, which will represent how the peat will behave under loading. This article presents the results of plate loading tests conducted on a site with thick deposits of peat in the region of Belarus and compares the test results with two mathematical models in an effort to determine which model best predicts behavior of peat soil.

The International Space Station (ISS) is an essential step in the ongoing evolution of spacecraft design. Building on lessons learned from shuttle/Mir and forging new ground, the ISS sets a new standard in the international integration of large-scale spacecraft on-orbit. There are lessons learned in this endeavor that have much utility for the next programs of manned exploration and large-scale integration. It is the purpose of this paper to highlight some of the mechanisms developed and lessons learned that hold much promise for future human space exploration.

Reduced and artificially induced gravity levels relative to the Earth's have major influences upon human operations, health and safety that must be carefully considered throughout all habitat planning and design processes. These considerations include influences upon astronaut/cosmonaut mobility, task performance, bone and muscle deterioration, fluid loss, psychological and spatial adaptation, and in the case of artificially induced gravity, impacts of Coriolis forces and cross-coupled accelerations. This paper will explore the various facets of spacecraft architecture and human factors design of space facilities for different gravity conditions, most particularly during long-term space flights. Included: (1) Partial gravity (Lunar and Mars); (2) Microgravity (Low Earth Orbit and Phobos/Deimos); and (3) Artificial gravity (centripetally induced). In designing for different gravity environments, architects must address both physical and psychological adaptation and operational problems for humans who exist beyond their natural environment. Included are complex adjustment problems such as those which will occur during transfers from one level of gravity to another. The main purpose is to create safe, comfortable facilities that optimize health, performance and morale.

The purpose of this discussion on human factors is to understand and predict the crew's needs during a mission to Mars, while on the surface of Mars, and during Earth return. Using a VaSIMR propulsion system our crew will spend three months en route to Mars and three months returning from Mars, after they have spent a year on the surface of Mars. This discusses how the vehicles and systems can be best designed to fit the crew's needs and limitations. It also discusses the physical and psychological challenges for the crew. The medical risks of this mission are outlined and the types of medical equipment needed to treat those medical problems are discussed.

This paper discusses some considerations and concepts for the development of a design for an inflatable living concept. One of the aims of space programs is to create an habitat in which crew can live and work efficiently for longer and continuous periods. Even though astronauts are favourite in living a unique experience, they are forced to stay in an environment that deeply change their behaviour, their habits and their psycophysical balance. To improve this situation it is necessary to create an habitat possibly more comfortable than present modules, and that wouldn't turn upside down in every way the habits that man has acquired living on Earth. Present rigid modules are mainly designed for machines and equipment and only in later man is considered for their use. This fact leads designers to create excessively rational spaces that are of inferior quality and sacrificed in their volume. Nowadays this attitude is changing in favour of a larger sensibility for human needs. The project `Astrophytum' is a practical attempt to give an improvement in the way of living in space. The `Astrophytum' is an inflatable module with a rigid core that is meant to consider man as the center of all, as the beginning and as the end of designing. The starting point is that man has innumerable needs, physical and psycological, that we must satisfy with our project. Therefore we want to offer in our project more comfort, countermeasures for micro-g, collective and personal spaces. In other words, we want to offer an habitat that can be a `house' and that can offer an acceptable way of living to people that are not accustomed to living in hardship. In the same way we want to answer to the new need of placing in rigid modules space- tourists as well, becouse the module `Astrophytum' is only concieved as habitation.

This paper discusses considerations and concepts for the design of a personal centrifuge for artificial gravity that is contained in an inflatable space module. Its primary purpose would be to serve as a countermeasure to the adverse effects of longterm exposure of the human body to microgravity. Several recent studies have concluded that it is possible for human crews to adapt to disorientation caused by Coriolis forces in a short radius facility. Based on this premise, this projects proposes to incorporate a 24 feet diameter centrifuge within an inflatable module to accommodate Shuttle launch constraints.

The goal of this project was to design a space vehicle prototype for a broad range of long-duration human missions in which gravity is a necessary condition. The concept features a tethered vehicle capable of providing rotationally induced gravity. An elliptical rather than a circular cross section was chosen for the habitable modules to optimize usable floor area for a gravity environment. The design of the pressurized modules focuses on the interior layout and ergonomics for a rotationally induced gravity environment. Other emphases include concepts for the module structure, tether retraction and dynamics, launch configuration, vehicle assembly, and the propulsion system.

Flight and research experience to date indicates that teams of robots and humans will provide significantly greater productivity and capabilities than either system working alone. This paper details research developments in the University of Maryland Space Systems Laboratory on three different approaches to human/robotic interaction in the space environment. In each of these, the human performing EVA is brought into closer interaction with the robotic system, with the ultimate conceptual goal being a symbiotic relationship between the human and the robot. In the first, a robotic actuator was integrated into a space suit glove, enabling hitherto unavailable dexterity without a penalty in crew fatigue. This "power glove" project paves the way for advanced robotic suit augmentation, including fully powered suits. In the second, advanced dexterous robot manipulators were integrated into the shuttle manipulator foot restraints, providing direct robotic capabilities for worksite preparation and closeout, and assisting the EVA crew during human operations. Results indicate productivity enhancements ranging from 60% to 400%, depending on the details of the tasks performed. In the last, a single-person , spacecraft was designed for space operations, incorporating both robotic manipulators and space suit arms. The system is capable of zero-prebreathe EVA and extended mission operations, while providing greater protection for the crew and reducing the number of crew necessary to conduct safe external operations.

We consider here the production of methane from the lunar regolith, for use as rocket propellant. Eagle Engineering described a process for producing hydrogen and oxygen from the lunar regolith; however, the amount of regolith needed to be processed and the energy needed for the processing were quite high. Methane, if it can be produced, has advantages with respect to the use of lunar hydrogen in that it is more easily stored and should be less easily lost from the production process, although it provides lower performance in rocket engines than hydrogen. It is well known that the carbon concentration of the lunar regolith is low, but at 100 ppm, there is about as much useful carbon as there is hydrogen, which has an average abundance of 50 ppm. Our study shows that significantly less regolith needs to be processed if methane is produced instead of hydrogen.

This paper aims to introduce the space architecture education at Bilkent University in Turkey. Architecture and engineering have common interests in Earth infrastructure development; as the space, considered as a new and challenging environment can help the students to undertake difficult tasks in developing space stations and various space structures for habitation purposes.

This paper discusses three architectures for the production of propellants on the Moon. Each architecture includes mining and processing equipment, a thermal reactor to extract the propellant, a means of liquefying gaseous propellant, and the power supply for running the system. Each system is sized to produce 1,000 kg of O₂ per month and, in the last two architectures, 167 kg of H₂, in order to obtain a mixture ratio H₂/O₂ = 1/6. The architectures are characterized in terms of input feedstock, output propellant, mass and power requirements, and necessary equipment for operations. The production plants have been designed using the approach of EEI (1988, 1991), with some of their assumptions for system efficiencies upgraded with more recent technologies.

Spaceports of the future will probably look like airports today, having similar infrastructure and design, but serve different markets: sub-orbital, orbital, and even inter-planetary transportation. The ideal state for any transportation system is to have efficient, safe, and low cost operations. In order to bring space transportation from its adolescence today into adulthood tomorrow, a paradigm shift must drive towards the definition and implementation of ground infrastructure standards for space transportation that will ultimately influence the design of the flight hardware. In order for spaceports of tomorrow to operate as efficiently as other transportation systems today, standardization is paramount.

American space launch is in crisis. One factor is the outdated launch infrastructure which is often decades old. This outdated infrastructure has played a key role in the decline of the American launch industry and efforts at space commercialization. A new agency is needed to modernize America's launch infrastructure to ensure American space commerce leadership in the future.

The vast quantities of solar energy available above the Earth, converted into useable electric power, will be increasingly needed to power the machines that so greatly amplify mankind's physical and mental activities throughout worldwide civilization. The construction and maintenance preparation of many huge Solar Satellite Power Stations in GEO awaits a transportation system adequate to the task, itself electrically powered and thus not subject to the fate of inevitable loss of major access to space due to inadequate fossil fuel energy sources needed for producing launch vehicle fuel. One way to eliminate the extremely inefficient need to lift massive fuel for the trip to space, is by lifting the spacecraft by electro-magnetically dragging against a continuous stream of upward-moving high velocity electric motor armature segments circulating within an enclosed hard vacuum in an OTT ellipse around the Earth from ground to GEO. This distributes the lift energy source all the way from ground to GEO, and the OTT-constrained-path armature mass stream generates centrifugal force at above OTV enough to balance the weight of the structure with its live loads. Unlike conventional structures, the flow of energy, here from the Sun to the resultant lift of payload from the ground to GEO, is of uniquely primary concern in such kinetic structures, since the internally stored energy supplies distributed lift energy for spacecraft everywhere along the transportation system, as well as providing the primary weight support of the structure, and powering position servo in response to wind and vehicular live loads, enabling vast access to space power.

The purpose of this paper is to present the basis of applying advanced mirror technology to aerospace applications with meter-class or larger apertures. The basic trend in advanced mirror technology away from traditional glass materials is leading to materials and manufacturing methods with the promise of reduced fabrication time and cost for large apertures. Derivations and discussions motivate a set of metrics for mirror performance and technology development, and scaling laws are generated for understanding the relationship between geometry and performance for a given technology.

NASA and the Air Force are looking to improve space borne telescopes by reducing areal density. One proposed alteration to make this reduction possible is to fabricate carbon fiber reinforced polymer (CFRP) mirrors using a mirror replication fabrication technique. This proposed alteration has proven to be a difficult and technical problem. The ability to successfully fabricate CFRP mirrors is limited by surface roughness and surface figure error. Two factors currently dominate the existence of both problems: fiber print through and unmatched shrinkage and expansion of fiber and matrix respectively, with changes in temperature. The purpose of this research is to isolate and quantify the dominating causes of surface roughness. With this, a cause- effect relation between materials, processes, and surface roughness can be established. In order to understand and quantify the problems involved with the mirror replication technique, reflection spectroscopy and microscopy methods are employed. Scatterometry measurements aid in the examining of common surface roughness parameters such as fiber print through, micro cracking, and anisotropy. Optical microscopy provides for the investigation of fiber/matrix interaction near the surface of the mirror replication samples. By observing this interaction a more detailed understanding of fiber print through is obtained as a function of the changes in fabrication processes. With the addition of resin film to the surface of the mirror, the effect of fiber print through is mitigated and any necessary surface correction is made possible. Comparing the results of mirror replication samples that were fabricated using various pressures and resin thickness describes how the curing process affects fiber print through and surface roughness.

The development of large-scale ultra lightweight mirrors has included research and development in the area of thin-film polymer membranes. Milestones have been achieved in the optical quality of polymers of interest cast into thin films as far as surface finish and thickness uniformity making them ideal for use as first surface mirrors. The next step is to develop a method of deployment and global figure control to maintain a correctable optical quality mirror. The use of Shape Memory Alloys (SMA), in particular Nitinol, is currently being researched as a means to provide energy to return a cast membrane mirror to a previously determined shape. Integration processes have been developed to integrate polymers of interest with SMA material that maintain good overall shape memory effect while retaining the high optical properties of the polymer. While the SMA is primarily used as a deployment method, additional non-contact actuation methods are also being investigated to properly correct and maintain the membrane mirror shape.

A Phase I & II Small Business Innovative Research contract awarded to Think Composites by the Air Force Research Laboratory undertook the task of analyzing and optimizing flywheel rotor designs, and obtaining spin test data for model verification and design improvement. Several designs were explored, manufactured, and tested with the "soft-core" flywheel rotor concept showing great promise. This paper gives an overview of the flywheel energy storage system, additionally soft core composite rotor design, rotor analysis, rotor fabrication, spin testing, and durability analysis (life prediction) is discussed.

The Air Force Research Laboratory, Space Vehicles Directorate, is currently investigating several composite design configurations for all composite bolted connection flanges. These efforts have been directed toward adapter connections for the Evolved Expendable Launch Vehicle (EELV). Designs were investigated and tested for the EELV Secondary Payload Adapter (ESPA) and for EELV 4 and 5-meter conic payload adapter variations with a 1780 mm forward connection diameter. These adapters support the payload(s) on the launch vehicle and must be carried to orbit with the payload. The original ESPA adapter design was conceived and developed as an aluminum ring structure to support a main payload and a cluster of six smaller payloads (each weighing a few hundred kilograms). Specimens with composite connections were designed fabricated by ATK and tested by AFRL. These were compared to the response of an ESPA equivalent aluminum substructure. Acceptable structure response was identified for several or these composite design alternatives. The 1780 mm payload adapter is being designed by Boeing (Huntington Beach) and built by ATK (Salt Lake City, UT and Iuka, MS) to provide improved adaptability to a variety of future commercial Delta IV and EELV missions. The design forces introduce high interlaminar tension stress at the bend of the flange. The resulting design makes limited use of composite Z-pinning to reinforce critical sections. Substructures were fabricated by ATK and designed and tested by Boeing. Additionally a complete conic substructure of the forward 50 cm of the adapter containing the composite forward flange has been built by ATK in Iuka, MS. AFRL tested this structure and the test results confirm that this composite flange can be used for a final design of the adapter shell.

The United States Air Force is developing a responsive Reusable Launch Vehicle (RLV) capability to accomplish military missions. This concept is referred to as the Military Spaceplane (MSP). The MSP requires both expendable and reusable upper stages to effectively achieve operational mission requirements. Both of these upper stage concepts are considering high-concentration hydrogen peroxide as their oxidizer, due to its responsiveness and operability. This paper will focus on the Air Force Research Laboratory's (AFRL) Upper Stage Flight Experiment (USFE) integral structure development effort. The integral structure refers to the stage skirt with an integral composite tank. Design and fabrication risk for the operational system has been mitigated via this program. The USFE tank is the world's first composite integral structure designed to be Class 1 compatible with high concentrations of hydrogen peroxide. Lightweight hydrogen peroxide compatible tankage development is of interest to the international aerospace community because it provides considerable benefits. Hydrogen peroxide and hydrocarbon fuel (H₂O₂/RP) can be stored unpressurized and are relatively non-toxic, which makes it safer to handle and store compared to bipropellants such as Nitrogen Tetraoxide and Monomethyl Hydrazine (NTO/MMH). In addition to being a viable bipropellant oxidizer, hydrogen peroxide can also serve as a monopropellant for an Attitude Control System (ACS).

As more powerful space systems emerge, radiator technology is challenged to dissipate the waste heat at minimum weight. Through the integration of thin aluminum sheet or low mass carbon fiber composites and high conductivity annealed pyrolytic graphite, the development of a new class of high performance weight efficient radiators is feasible. A radiator concept based on k Technology Corporation's (kTC) high conductivity encapsulated annealed pyrolytic graphic materials (k-Core) has demonstrated this concept. APG is a highly crystalline material with a room temperature thermal conductivity of 1700 W/mK and density of 2.26 g/cm³. This design concept can manage high thermal flux systems, have small thermal distortions and be highly survivable. kTC's k-Core radiator concept outperformed a baseline aluminum/heat pipe design by a factor of five. The k-Core concept with 8 inch spaced heat pipes outperformed the baseline aluminum design with 4 inch heat pipe spacing by nearly a factor of three. This paper will present the completed work including the measured performance of these k-Core radiators.

A recent advancement in technology for deployable spacecraft structures has been the development of elastic memory composite (EMC) materials that exhibit high-strain-capacity and shape memory characteristics. EMC materials can be folded to very high induced strain and "frozen" in this folded state through a very specific thermo-mechanical cycle. Subsequently, the "frozen" strains can be recovered by re-heating the part. The ability to internally contain strain energy provides an advantage over traditional high-strain materials (e.g., S2-glass/epoxy). The present paper will focus on a program to develop carbon-fiber-reinforced EMC coilable longerons for the CoilABLE^TM boom. Specifically, the present paper will include: (1) a description of the baseline design corresponding to the CoilABLE ground test article, (2) a discussion on the mechanics of inducing high strain into EMC materials, (3) development of the EMC longerons, and (4) results from the assembly and testing of the final test article.

This paper presents an overview of research related to automated production of high performance composite space structures conducted at KaZaK Composites Incorporated (KCI) using funding from a variety of government and commercial sources. The performance of composite materials is dependent in nearly equal parts upon composition and processing, and pultrusion processing offers a unique combination of performance and economy. This unique capability can enable mission applications that are otherwise impractical Pultrusion is a highly automated manufacturing technology that produces finished composite parts as a continuous stream, much like metal extrusion. In its most familiar commercial applications, pultrusion is used to make commodity hardware such as ladder rails and tool handles. In this paper, KCI will demonstrate that pultrusion can be adapted to produce flight hardware that is both lower in cost and of higher performance than similar products made by other manufacturing technologies. Indeed pultrusion is sometimes the only viable manufacturing approach for important classes of flight hardware. Five "case studies" will be presented as a means of illustrating the wide range of materials and structures for which pultrusion is the key enabling technology.

Currently on orbit deployment of large structural components is accomplished via heavy, high part count mechanisms, which have unfavorable frequency response characteristics. These existing deployment mechanisms may, in the future, be replaced by shape memory or Elastic Memory Composite (EMC) components. Many of these deployable components require precise control of their deployed position. However, there is concern that prior to launch, during transport and staging, these structural components may experience thermal cycles due to repeated exposure to direct sunlight, which may result in reduced deployment accuracy. An experimental effort was conducted at the Air Force Research Laboratory, Space Vehicles Directorate, at Kirtland AFB, NM., to determine whether or not this degradation actually occurs in this material.

The use of telescopic rigidizable inflatably-deployed booms for the space deployment and support of membrane optics for space shows great promise because of their light weight and small packaged volume. The telescopic boom deployment mechanism is extremely simple with almost zero parasitic mass for deployment control. We have shown on a subscale level that they possess excellent deployment reliability, package in a minimum launch volume, and cost approximately an order of magnitude less than equivalent mechanical deployable structures. The two major issues in the use of telescopically-deployed membrane optics systems are (a) rigidization scheme and (b) deployment control. The rigidization method chosen is the Sub-Tg: in the Sub-Tg method, rigidization is achieved by letting the Sub-Tg resin impregnated boom passively cool below the resin glass-transition temperature (Tg). The Tg is tailorable and the choice depends on the mission thermal environment. The controlled deployment is achieved by using a unique concentric packaging arrangement about the boom axis, similar to that of a telescoping tube. Controlled deployment of subscale rigidizable telescopic conical booms has been demonstrated in the laboratory for booms up to 7m long. In the present paper, we present the use of the telescopic conical boom concept with the Sub-Tg method of rigidization as applied to a membrane optics system with an optical error-correction system.

The S.P.A. EGS (Moscow) is specialized in design and manufacture of large deployable antennae (LDA) for the communication satellites whose life-in-service comprises no less then 15 years. For the purpose of installation on geostationary satellites, the S.P.A. EGS designed a series of parabolic antennae with mesh reflectors differing by their dimensions and means of their supporting, stowing, deploying and prestressing. The large space antennae projects are based on application of a closed polygonal pantograph truss used for transforming, deploying and prestressing the reflector structure. Their reflecting surfaces represent a flexible mesh fabric. Two means of the surface maintaining are discussed. The first technique is associated with employment of forces of the gravity field gradient. The second one is based on the use of a flexible carcass prestressed by internal forces applied to the pantograph. The reflectors of the second kind have rather complicated mechanical structure depending on the way of their attachment to a carrier. Provisions are made for supporting the reflector by an articulated arm linked with its central interface and through the use of tube beams, supporting the reflector periphery structures. During the design of the reflectors special attention was payed to the problems of their structural simulations at the stages of their launching, deployment and orbital motion. The considered deployable antennae can be enabling elements of many space missions ranging from communications to many other satellite systems, including radar, remote sensing, interferometry, wireless power transmission etc. They exhibit enhanced stiffness of the structure, required for the digit tele- and radio-communication and navigation, which makes it possible to diminish the ray scattering, to rise the power of the accepted signals and to prevent the frequency losses.

Touchstone Research Laboratory, Ltd., was recently awarded Phase I and II Small Business Technology Transfer (STTR) grants by the Missile Defense Agency (MDA). The primary objective of the Phase I effort was to demonstrate feasibility of carbon foam technologies (CFOAM®) on future MDA structural and thermal protection systems (TPS). Other space agencies may benefit from carbon foam technology as well due to the potential increase in TPS durability and cost savings. The space shuttle orbiter routinely requires considerable time and facilities for maintenance between flights. The two most expensive maintenance systems for the orbiter are the engines and the TPS. The TPS alone is estimated to require about 40,000 hours of maintenance between flights. Carbon foam technology is anticipated to provide selective thermally insulating and conductive zones, respectively, for thermal management. CFOAM thermophysical properties such as thermal conductivity, thermal expansion, and density are presented with Finite Element Model (FEM) analysis results. Phase I efforts ended in May 2003, and future Phase II work is briefly described.

A new family of fiber reinforced, sinter resistant, IR opacified silica aerogel composites developed and commercialized by Aspen Aerogels Inc. is described. The materials are the best existing thermal insulators for continuous use applications between room temperature and 650°C. Experimental aerogel composites for short-term high heat load applications with the temperatures up to 1200°C are reported. The factors affecting the performance of the high temperature aerogel composites are discussed.

Lightweight aerogel composites developed at Aspen Aerogels, Inc. have been evaluated as potential replacement of Multi-Layer Insulation (MLI) in space based platforms. The thermal performance of aerogel in vacuum (from cryogenic temperatures to 160°C) and its outgassing rates at 10^– torr and ambient temperature was tested. With a density of 0.03g/cc and thermal conductivity below 1mW/mK at 5 x 10^– torr, the nanoporous flexible aerogel can give excellent thermal and micrometeorite protection at launch and in LEO. The composites are easier to install than MLI and have more consistent thermal performance irrespective of inadvertent compression during installation on complex shaped structures. The extremely fast outgassing rates and low residuals make aerogel composites desirable for space use and hold great promise for efficient thermal management of cryogenic subsystems and optics on space platforms.

The solar sail is one of the NASA's high priority advanced space transportation systems. Solar sailing provides a practical way for space exploration missions. Solar sails do not need to carry an active main propulsion system. Through the continuously low thrust propulsion from the solar radiation pressure, the interplanetary transportation for space exploration missions in solar system would be realized. In this paper, dynamic behavior of a square sail under direct solar radiation pressure is investigated. A finite element model of a square sail consisting of four triangular shaped membranes and four pre-stressed tubular booms is developed. Results are presented for different loading cases in order to study effects of straight edge cords and uniform thermal distribution across the sail. It is seen that structural response of the membrane is relatively small in comparison with the sail dimension. Results showed that straight edge cord does not have much effect on the sail structural performance. However, a uniform temperature change across the structure in the structure increases significantly the lateral deformation of the membrane due to the considerable difference between membrane and booms.

The Aurora Programme of the European Space Agency is dedicated to the robotic and human exploration of the Solar System bodies holding promises of traces of life, In this frame the programme is also preparing Europe for a participation in a possible human mission to Mars, expected to become a reality by the years around 2030. In order to reach this goal a series of robotic Mars missions are planned. The acquisition of knowledge related to the existence of traces of past or present life on Mars is considered a prerequisite for future human missions. ExoMars, the first major mission of the Aurora programme, planned to be launched in 2009, foresees a Mars surface rover equipped with an "exobiology" or "astrobiology" payload package to examine several samples of mars soil and collect scientific data.

The Martian Radiation Environment Experiment (MARIE) instrument is currently orbiting Mars aboard the Mars Odyssey spacecraft. During its cruise to Mars, it returned radiation environment data from interplanetary space, and now in Mars orbit, it continues to measure the radiation dose contributions of both Galactic Cosmic Rays (GCR) and Solar Proton Events (SPE). Data accumulated over almost the full year of Odyssey science operations compares unshielded integrated radiation dose equivalent in Mars orbit to internal detectors aboard the International Space Station. The findings show that the integrated radiation dose (combining GCR and SPE) is consistently higher in Odyssey's 400 km polar orbit than in ISS' 400 km Low Earth Orbit (LEO), on average about a factor or 2.5. MARIE measured 450mSv integrated annual dose equivalent as compared to the 170mSv/year measured aboard the ISS. This confirms expected results, since there is reduced solid angle shielding due to Mars' size as well as the absence of Earth's magnetosphere. No surface radiation measurements exist to accompany the Mars orbital data. Surface measurements have been identified as the highest priority in the National Research Council's "Safe on Mars" report, and coincident surface and orbital measurements are necessary to model the shielding effect of the Martian atmosphere. It is assumed that dose equivalent on the surface will be reduced a factor of 2 simply by geometry, and an additional reduction will come from shielding by the atmosphere. This paper examines how using the measured radiation doses and comparing them to Low Earth Orbit dose equivalent guidelines, the total radiation dose expected for a 3-year human Mars mission is within current limits for astronauts. It also discussed how the GCR and SPE mix in interplanetary space is significantly different than for LEO, and how further biological research is needed to assess the biological effects of long-term exposure to GCR. MARIE data indicates that approximately 15% of the integrated dose contribution comes from SPE sources. Until further biological research is performed, and surface radiation measurements made, determination of absolute dose a human crew would experience, the effect of high GCR interplanetary doses, and the relationship to our LEO experience will remain estimates.

In previous studies of centripetally induced artificial gravity for use in orbital habitats and other long-duration space facilities, large diameter rotating habitats are shown to provide suitable living and working quarters for long-term missions in space. One of the important practical issues typically missing from these discussions is the need for a central, non-rotating hub for docking resupply and crew-exchange vehicles. The issue is how to move equipment, supplies, and personnel between the crew quarters and facilities on the habitat's revolving rim and the docking and loading platforms in the stationary core. This presentation proposes a solution to this issue.

The establishment of long-term space habitats our outposts represent a new frontier for manufacturing. Benefits of space-based industrial process include zero- or micro-gravity, a high-quality vacuum, an infinite heat sink (and high temperature gradients) and a limitless supply of high-energy particles. Previous experiments in U.S. and Russian missions involved in easy-manufacturing experiments, as the future can be opened for further industrial exploration relying on the availability of resources and location of markets. This paper discusses industrial processes in space manufacturing and necessary technologies to develop a space-based manufacturing business reviewing the design process of Japanese asteroid sample return mission (MUSES-C) and possible future space-oriented markets connected with Near-Earth Object retrieval concepts.

Hypersonic air breathing vehicle will be one of the largest technological challenges in the aeronautical community during the twenty first century. The key to this type of transportation is the technological mastery of the propulsion system. The design of the curve shaped fore body of the vehicle leads to the role of compression ramp that reduces the flow speed ahead of the air inlet to increase the propulsive efficiency. The study of curve shaped fore body and flat shaped fore body conducted in MIT Low speed wind tunnel and the experimental data's are collected. This analysis also carried out in Computational Fluid Dynamics (CFD) package STAR CD. Out of this research the curve shaped fore body increases the lift of the whole hypersonic body, which leads to horizontal take off and landing of hypersonic vehicle. The results found out from the computational as well as experimental leads to give the aerodynamic database for further research in hypersonic research vehicles.