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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Current Trends. Spacecraft Miniaturization (while maintaining reliability), Rapid, Low Cost Implementation, Low Cost Mission Operations, Less Dependence on Nuclear Fuel, Technology Commercialization.
Since beginning operations in 1999, the MODIS Adaptive Processing System (MODAPS) has evolved to take advantage of trends in information technology, such as the falling cost of computing cycles and disk storage and the availability of high quality open-source software (Linux, Apache and Perl), to achieve substantial gains in processing and distribution capacity and throughput while driving down the cost of system operations.
A phased-array system comprised of custom-made and commercially available microelectromechanical system (MEMS) silicon microphones and custom ancillary hardware has been developed for use in aeroacoustic testing in hard-walled and acoustically treated wind tunnels. Recent advances in the areas of multi-channel signal processing and beam forming have driven the construction of phased arrays containing ever-greater numbers of microphones. Traditional obstacles to this trend have been posed by (1) the high costs of conventional condenser microphones, associated cabling, and support electronics and (2) the difficulty of mounting conventional microphones in the precise locations required for high-density arrays. The present development overcomes these obstacles. One of the hallmarks of the new system is a series of fabricated platforms on which multiple microphones can be mounted. These mounting platforms, consisting of flexible polyimide circuit-board material (see left side of figure), include all the necessary microphone power and signal interconnects. A single bus line connects all microphones to a common power supply, while the signal lines terminate in one or more data buses on the sides of the circuit board. To minimize cross talk between array channels, ground lines are interposed as shields between all the data bus signal lines. The MEMS microphones are electrically connected to the boards via solder pads that are built into the printed wiring. These flexible circuit boards share many characteristics with their traditional rigid counterparts, but can be manufactured much thinner, as small as 0.1 millimeter, and much lighter with boards weighing as much as 75 percent less than traditional rigid ones. For a typical hard-walled wind-tunnel installation, the flexible printed-circuit board is bonded to the tunnel wall and covered with a face sheet that contains precise cutouts for the microphones. Once the face sheet is mounted, a smooth surface is established over the entire array due to the flush mounting of all microphones (see right side of figure). The face sheet is made from a continuous glass-woven-fabric base impregnated with an epoxy resin binder. This material offers a combination of high mechanical strength and low dielectric loss, making it suitable for withstanding the harsh test section environment present in many wind tunnels, while at the same time protecting the underlying polyimide board. Customized signal-conditioning hardware consisting of line drivers and antialiasing filters are coupled with the array. The line drivers are constructed using low-supply-current, high-gain-bandwidth operational amplifiers designed to transmit the microphone signals several dozen feet from the array to external acquisition hardware. The anti-alias filters consist of individual Chebyshev low-pass filters (one for each microphone channel) housed on small printed-circuit boards mounted on one or more motherboards. The mother/daughter board design results in a modular system, which is easy to debug and service and which enables the filter characteristics to be changed by swapping daughter boards with ones containing different filter parameters. The filter outputs are passed to commercially- available acquisition hardware to digitize and store the conditioned microphone signals. Wind-tunnel testing of the new MEMS microphone polyimide mounting system shows that the array performance is comparable to that of traditional arrays, but with significantly less cost of construction.
There is a trend of compromising verification testing to address the cost and schedule constraints, which poses a high-risk posture for programs/projects. Current and emerging aerospace scientific and/or human exploration programs continue to pose new technological challenges. These technological challenges combined with finite budgets and truncated schedules are forcing designers, scientists, engineers, and managers to push technologies to their physical limits. In addition, budget and schedule pressures challenge how those technologies/missions are verified. A clear understanding of the different verification processes is needed to ensure the proper verification of the technology within the mission (i.e., capabilities, advantages, and limitations). The goal of verification is to prove through test, analysis, inspection, and/or demonstration that a product provides its required function while meeting the performance requirements. It is important that verification yield understanding of representative performance under worst-case conditions so that margins to failure can be evaluated for proposed applications. The capabilities, advantages, and limitations of the testing and inspection performed at each level are different, and the risk incurred by omitting a verification step depends on the level of integration as well as Mission, Environment, Application and Lifetime (MEAL). This paper focuses on verification processes. The goal of the verification process is to ensure the given avionics technology could be safely implemented on the given MEAL consistent with the program/project risk posture.
Cost, performance and functionality concerns are driving a trend towards use of self-sufficient autonomous systems in place of human-controlled mechanisms.
The trend in the design of advanced transonic fans for aircraft engines has been toward the use of complex high-aspect-ratio blade geometries with a larger number of blades and higher loading. In addition, integrally bladed disks or blisks are being considered in fan designs for their potential to reduce manufacturing costs, weight, and complexity by eliminating attachments. With such design trends, there is an increased possibility within the operating region of part-speed stall flutter (self-excited vibrations) that is exacerbated by the reduced structural damping of blisk fans. To verify the aeroelastic soundness of the design, the NASA Glenn Research Center is developing and validating an accurate aeroelastic prediction and analysis capability. Recently, this capability was enhanced significantly as described here.
Reasonable evolutionary trends in federal outlays for aerospace research and development predict a continuing decline in real resources (1970 dollars) until the mid eighties, and a growth thereafter to the 1970 level by 2000, still well below the 1966 peak. Employment levels will parallel this trend with no shortage of available personnel foreseen. These trends characterize a maturing industry. Shifts in outlook toward the economic use of resources, rather than minimum risk at any cost, and toward missions aligned with societal needs and broad national goals will accompany these trends. These shifts in outlook will arise in part in academia, and will, in turn, influence engineering education. By 2000, space technology will have achieved major advances in the management of information, in space transportation, in space structures, and in energy. The economics of space systems must be the primary consideration if the space program foreseen for the 21st century is to become an actuality.
There has been significant improvement in the performance of VLSI devices, in terms of size, power consumption, and speed, in recent years and this trend may also continue for some near future. However, it is a well known fact that there are major obstacles, i.e., physical limitation of feature size reduction and ever increasing cost of foundry, that would prevent the long term continuation of this trend. This has motivated the exploration of some fundamentally new technologies that are not dependent on the conventional feature size approach. Such technologies are expected to enable scaling to continue to the ultimate level, i.e., molecular and atomistic size. Quantum computing, quantum dot-based computing, DNA based computing, biologically inspired computing, etc., are examples of such new technologies. In particular, quantum-dots based computing by using Quantum-dot Cellular Automata (QCA) has recently been intensely investigated as a promising new technology capable of offering significant improvement over conventional VLSI in terms of reduction of feature size (and hence increase in integration level), reduction of power consumption, and increase of switching speed. Quantum dot-based computing and memory in general and QCA specifically, are intriguing to NASA due to their high packing density (10(exp 11) - 10(exp 12) per square cm ) and low power consumption (no transfer of current) and potentially higher radiation tolerant. Under Revolutionary Computing Technology (RTC) Program at the NASA/JPL Center for Integrated Space Microelectronics (CISM), we have been investigating the potential applications of QCA for the space program. To this end, exploiting the intrinsic features of QCA, we have designed novel QCA-based circuits for co-planner (i.e., single layer) and compact implementation of a class of data permutation matrices, a class of interconnection networks, and a bit-serial processor. Building upon these circuits, we have developed novel algorithms and QCA-based architectures for highly parallel and systolic computation of signal/image processing applications, such as FFT and Wavelet and Wlash-Hadamard Transforms.
The purpose of this text is to provide the reader with the background, understanding, and computational tools needed to master the practical aspects of photovoltaic (PV) technology, application, and cost. The focus is on stand-alone, silicon solar cell, flat-plate systems in the range of 1 to 25 kWh/day output. Technology topics covered include operation and performance of each of the major system components (e.g., modules, array, battery, regulators, controls, and instrumentation), safety, installation, operation and maintenance, and electrical loads. Application experience and trends are presented. Indices of electrical service performance - reliability, availability, and voltage control - are discussed, and the known service performance of central station electric grid, diesel-generator, and PV stand-alone systems are compared. PV system sizing methods are reviewed and compared, and a procedure for rapid sizing is described and illustrated by the use of several sample cases. The rapid sizing procedure yields an array and battery size that corresponds to a minimum cost system for a given load requirement, insulation condition, and desired level of service performance. PV system capital cost and levelized energy cost are derived as functions of service performance and insulation. Estimates of future trends in PV system costs are made.
A brief historical review of time transfer techniques used during the last twenty years is presented. Methods currently used are discussed in terms of cost effectiveness as a function of accuracy achievable. Future trends are also discussed in terms of projected timekeeping capabilities.
Program Management Summary; Organizational structure is established. Roles and responsibilities are well defined: a) All major contracts are in place. b) All foreign partners are in place, operating under signed Memoranda of Understanding (MOUs). c) Partners include GSFC, NGST, Ball, ITT, ATK, STScI, ESA, CSA, UAz, LM, JPL, MSFC, ARC, JSC, etc. All enabling technologies are at Technical Readiness Level-6. Earned Value Management is being applied to all major contracts consistent with Agency guidance. Schedules are baselined and the project critical path is understood/managed. Budget with reserves established. Liens and threats system in use. Formal Configuration Management (CM) processes are in place. Project-level schedules are maintained within the CM system. Formal Risk Management processes are in place. Requirements are stable and flowed down. Project metrics are established and tracked monthly: a) Includes technical as well as cost and schedule metrics. b) Changes as well as trends are reported each month.
This paper presents the approach and results for the Aeronautics Test Program (ATP) FY11 Facility Assessment Project. ATP commissioned assessments in FY07 and FY11 to aid in the understanding of the current condition and reliability of its facilities and their ability to meet current and future (five year horizon) test requirements. The principle output of the assessment was a database of facility unique, prioritized investments projects with budgetary cost estimates. This database was also used to identify trends for the condition of facility systems.
Some basic trends in fighters are traced from the post World II era. Beginning with the first operational jet fighter, the P-80, the characteristics of subsequent fighter aircraft are examined for performance, mission capability, effectiveness, and cost. Characteristics presented include: power loading, wing loading, maximum speed, rate of climb, turn rate, weight and weight distribution, cost and cost distribution. The characteristics of some USSR aircraft are included for comparison. The trends indicate some of the rationale for certain fighter designs and some likely characteristics to be sought in future fighter aircraft designs.
The integration of payload instruments into the Command and Data Management Subsystem (CDMS) of the Space Shuttle Spacelab is discussed. Specific emphasis is on the distributed (self-contained processor) vs centralized (Spacelab Computer) approach to science payload utilization of these control and data handling capabilities. An overview of the Spacelab CDMS is first given. A synopsis of the integration process for Spacelab Missions 1, 2, and 3 is discussed. Three different hardware approaches to payload command and data handling are then categorized from which Spacelab implementations to date are derived. The different types of Spacelab Mission 3 payload CDMS hardware and software being used are discussed, including examples of microprocessors and data acquisition systems. Preliminary costs for Spacelab application software vs other flight software approaches are compared. A standard RAU interface that would permit a range of ECOS services to be provided, yet be implemented as a mass-produceable unit for incorporation into payloads, is proposed, in keeping with the trend toward simplifying the integration effort, standardizing CDMS interfaces, and ultimately lowering cost.
We have applied a future mission architecture, the Autonomous Nano-Technology Swarm (ANTS), to a proposed mission for in situ survey, or prospecting, of the asteroid belt, the Prospecting Asteroid Mission (PAM) as part of a NASA 2003 Revolutionary Aerospace Concept (RASC) study. ANTS architecture builds on and advances recent trends in robotics, artificial intelligence, and materials processing to minimize costs and maximize effectiveness of space operations. PAM and other applications have been proposed for the survey of inaccessible, high surface area populations of great interest from the standpoint of resources and/or solar system origin. The ANTS architecture is inspired by the success of social insect colonies, a success based on the division of labor within the colonies in two key ways: 1) within their specialties, individual specialists generally outperform generalists, and 2) with sufficiently efficient social interaction and coordination, the group of specialists generally outperforms the group of generalists. Thus systems designed as ANTS are built from potentially very large numbers of highly autonomous, yet socially interactive, elements. The architecture is self-similar in that elements and sub-elements of the system may also be recursively structured as ANTS on scales ranging from microscopic to interplanetary distances. Here, we analyze requirements for the mission application at the low gravity target end of the spectrum, the Prospecting Asteroid Mission (PAM), and for specialized autonomous operations which would support this mission. ANTS as applied to PAM involves the activities of hundreds of individual specialist 'sciencecraft'. Most of them, called Workers, carry and operate eight to nine different scientific instruments, as listed in the table, including spectrometers, ranging and radio science devices, and imagers. The remaining specialists, Messenger/Rulers, provide communication and coordination functions among specialists operating autonomously as individuals, team members, and subswarms.
Human Systems Integration principles and methods can be used to help integrate people, technology, and organizations in an effective and efficient manner. Over the past decade, a wide range of tools, techniques, and technologies have been developed by federal agencies to achieve significant cost and performance benefits. In this discussion, we will explore trends in military human systems integration and learn about the critical role being played by human performance and effectiveness research. We will also examine case studies on the planning and design of future human space flight vehicles, the national air space system and the first nuclear reactors to be built in the United States in over 30 years. And with an eye toward sustaining the discipline s principles and methods, we ll take a look at educating and training the next generation of human systems integration practitioners.
Weight has been used as the primary input variable for cost estimating almost as long as there have been parametric cost models. While there are good reasons for using weight, serious limitations exist. These limitations have been addressed by multi-variable equations and trend analysis in models such as NAFCOM, PRICE, and SEER; however, these models have not be able to address the significant time lags that can occur between the development of similar space flight hardware systems. These time lags make the cost analyst's job difficult because insufficient data exists to perform trend analysis, and the current set of parametric models are not well suited to accommodating process improvements in space flight hardware design, development, build and test. As a result, people of good faith can have serious disagreement over the cost for new systems. To address these shortcomings, new cost modeling approaches are needed. The most promising approach is process based (sometimes called activity) costing. Developing process based models will require a detailed understanding of the functions required to produce space flight hardware combined with innovative approaches to estimating the necessary resources. Particularly challenging will be the lack of data at the process level. One method for developing a model is to combine notional algorithms with a discrete event simulation and model changes to the total cost as perturbations to the program are introduced. Despite these challenges, the potential benefits are such that efforts should be focused on developing process based cost models.
Some basic trends in fighter aircraft are traced from the post World War II era. Beginning with the first operational jet fighter, the P-80, the characteristics of subsequent fighter aircraft are examined in terms of performance, mission capability, effectiveness, and cost. Characteristics presented include such items as power loading, wing loading, maximum speed, rate of climb, turn rate, weight and weight distribution, cost and cost distribution. In some cases, the characteristics of U.S.S.R. aircraft are included for comparison. The trends indicate some of the rationale for certain fighter designs and indicate some likely characteristics to be sought in future fighter aircraft designs.