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At least 1,621 records · Page 90
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NASA NTRS2006

SACD's Support of the Hyper-X Program

NASA s highly successful Hyper-X program demonstrated numerous hypersonic air-breathing vehicle related technologies including scramjet performance, advanced materials and hot structures, GN&C, and integrated vehicle performance resulting in, for the first time ever, acceleration of a vehicle powered by a scramjet engine. The Systems Analysis and Concepts Directorate (SACD) at NASA s Langley Research Center played a major role in the integrated team providing critical support, analysis, and leadership to the Hyper-X Program throughout the program s entire life and were key to its ultimate success. Engineers in SACD s Vehicle Analysis Branch (VAB) were involved in all stages and aspects of the program, from conceptual design prior to contract award, through preliminary design and hardware development, and in to, during, and after each of the three flights. Working closely with other engineers at Langley and Dryden, as well as industry partners, roughly 20 members of SACD were involved throughout the evolution of the Hyper-X program in nearly all disciplines, including lead roles in several areas. Engineers from VAB led the aerodynamic database development, the propulsion database development, and the stage separation analysis and database development effort. Others played major roles in structures, aerothermal, GN&C, trajectory analysis and flight simulation, as well as providing CFD support for aerodynamic, propulsion, and aerothermal analysis.

Robinson, Jeffrey S.↗
NASA NTRS2007

Model Checking Abstract PLEXIL Programs with SMART

We describe a method to automatically generate discrete-state models of abstract Plan Execution Interchange Language (PLEXIL) programs that can be analyzed using model checking tools. Starting from a high-level description of a PLEXIL program or a family of programs with common characteristics, the generator lays the framework that models the principles of program execution. The concrete parts of the program are not automatically generated, but require the modeler to introduce them by hand. As a case study, we generate models to verify properties of the PLEXIL macro constructs that are introduced as shorthand notation. After an exhaustive analysis, we conclude that the macro definitions obey the intended semantics and behave as expected, but contingently on a few specific requirements on the timing semantics of micro-steps in the concrete executive implementation.

Siminiceanu, Radu I.↗
NASA NTRS1978

Computer Programs (Turbomachinery)

NASA computer programs are extensively used in design of industrial equipment. Available from the Computer Software Management and Information Center (COSMIC) at the University of Georgia, these programs are employed as analysis tools in design, test and development processes, providing savings in time and money. For example, two NASA computer programs are used daily in the design of turbomachinery by Delaval Turbine Division, Trenton, New Jersey. The company uses the NASA splint interpolation routine for analysis of turbine blade vibration and the performance of compressors and condensers. A second program, the NASA print plot routine, analyzes turbine rotor response and produces graphs for project reports. The photos show examples of Delaval test operations in which the computer programs play a part. In the large photo below, a 24-inch turbine blade is undergoing test; in the smaller photo, a steam turbine rotor is being prepared for stress measurements under actual operating conditions; the "spaghetti" is wiring for test instrumentation

Source record↗
NASA NTRS2008

Verification and Planning Based on Coinductive Logic Programming

Coinduction is a powerful technique for reasoning about unfounded sets, unbounded structures, infinite automata, and interactive computations [6]. Where induction corresponds to least fixed point's semantics, coinduction corresponds to greatest fixed point semantics. Recently coinduction has been incorporated into logic programming and an elegant operational semantics developed for it [11, 12]. This operational semantics is the greatest fix point counterpart of SLD resolution (SLD resolution imparts operational semantics to least fix point based computations) and is termed co- SLD resolution. In co-SLD resolution, a predicate goal p( t) succeeds if it unifies with one of its ancestor calls. In addition, rational infinite terms are allowed as arguments of predicates. Infinite terms are represented as solutions to unification equations and the occurs check is omitted during the unification process. Coinductive Logic Programming (Co-LP) and Co-SLD resolution can be used to elegantly perform model checking and planning. A combined SLD and Co-SLD resolution based LP system forms the common basis for planning, scheduling, verification, model checking, and constraint solving [9, 4]. This is achieved by amalgamating SLD resolution, co-SLD resolution, and constraint logic programming [13] in a single logic programming system. Given that parallelism in logic programs can be implicitly exploited [8], complex, compute-intensive applications (planning, scheduling, model checking, etc.) can be executed in parallel on multi-core machines. Parallel execution can result in speed-ups as well as in larger instances of the problems being solved. In the remainder we elaborate on (i) how planning can be elegantly and efficiently performed under real-time constraints, (ii) how real-time systems can be elegantly and efficiently model- checked, as well as (iii) how hybrid systems can be verified in a combined system with both co-SLD and SLD resolution. Implementations of co-SLD resolution as well as preliminary implementations of the planning and verification applications have been developed [4]. Co-LP and Model Checking: The vast majority of properties that are to be verified can be classified into safety properties and liveness properties. It is well known within model checking that safety properties can be verified by reachability analysis, i.e, if a counter-example to the property exists, it can be finitely determined by enumerating all the reachable states of the Kripke structure.

Bansal, Ajay↗
NASA NTRS2006

New Directions for NASA's Advanced Life Support Program

Advanced Life Support (ALS), an element of Human Systems Research and Technology s (HSRT) Life Support and Habitation Program (LSH), has been NASA s primary sponsor of life support research and technology development for the agency. Over its history, ALS sponsored tasks across a diverse set of institutions, including field centers, colleges and universities, industry, and governmental laboratories, resulting in numerous publications and scientific articles, patents and new technologies, as well as education and training for primary, secondary and graduate students, including minority serving institutions. Prior to the Vision for Space Exploration (VSE) announced on January 14th, 2004 by the President, ALS had been focused on research and technology development for long duration exploration missions, emphasizing closed-loop regenerative systems, including both biological and physicochemical. Taking a robust and flexible approach, ALS focused on capabilities to enable visits to multiple potential destinations beyond low Earth orbit. ALS developed requirements, reference missions, and assumptions upon which to structure and focus its development program. The VSE gave NASA a plan for steady human and robotic space exploration based on specific, achievable goals. Recently, the Exploration Systems Architecture Study (ESAS) was chartered by NASA s Administrator to determine the best exploration architecture and strategy to implement the Vision. The study identified key technologies required to enable and significantly enhance the reference exploration missions and to prioritize near-term and far-term technology investments. This technology assessment resulted in a revised Exploration Systems Mission Directorate (ESMD) technology investment plan. A set of new technology development projects were initiated as part of the plan s implementation, replacing tasks previously initiated under HSRT and its sister program, Exploration Systems Research and Technology (ESRT). The Exploration Life Support (ELS) Project, under the Exploration Technology Development Program, has recently been initiated to perform directed life support technology development in support of Constellation and the Crew Exploration Vehicle (CEV). ELS) has replaced ALS, with several major differences. Thermal Control Systems have been separated into a new stand alone project (Thermal Systems for Exploration Missions). Tasks in Advanced Food Technology have been relocated to the Human Research Program. Tasks in a new discipline area, Habitation Engineering, have been added. Research and technology development for capabilities required for longer duration stays on the Moon and Mars, including bioregenerative system, have been deferred.

Barta, Daniel J.↗
NASA NTRS2007

Implementing an Applied Science Program

The work implied in the NASA Applied Science Program requires a delicate balancing act for the those doing it. At the implementation level there are multiple tensions intrinsic to the program. For example each application of an existing product to a decision support process requires deep knowledge about the data and deep knowledge about the decision making process. It is highly probable no one person has this range of knowledge. Otherwise the decision making process would already be using the data. Therefore, a team is required. But building a team usually requires time, especially across agencies. Yet the program mandates efforts of relatively short duration. Further, those who know the data are scientists, which makes them essential to the program. But scientists are evaluated on their publication record. Anything which diverts a scientist from the research for his next publication is an anathema to him and potential death to their career. Trying to get another agency to use NASA data does not strike most scientists as material inherently suitable for publication. Also, NASA wishes to rapidly implement often substantial changes to another agency's process. For many reasons, such as budget and program constraints, speed is important. But the owner of a decision making process is tightly constrained, usually by law, regulation, organization and custom. Changes when made are slow, cautious, even hesitant, and always done according a process specific to the situation. To manage this work MSFC must balance these and other tensions. Some things we have relatively little control over, such as budget. These we try to handle by structural techniques. For example by insisting all of our people work on multiple projects simultaneously we inherently have diversification of funding for all of our people. In many cases we explicitly use some elements of tension to be productive. For example the need for the scientists to constantly publish is motivation to keep tasks short and to the immediate point. As another example, the DSS agency and it personnel are treated as integral to the effort at every step. Thus, their ways of doing things, their problems and their assets become part of the solution. MSFC also manages the Applied Science work' within a strategic framework.' First, the scientists are necessarily at the core of all of this work as well as all of the work within the larger' organization. We therefore strive to keep a roughly 50-50 balance between the work done on tasks funded directly by the research side of NASA's Science Mission Directorate and funding from the applied side. Done at both the organization level and the level of the individual, this keeps the scientist both happy and productive over the long term. We also try diligently to remove as much burden from the scientist as practical by employing people such as the authors and others to do tasks not requiring; scientific knowledge. We also have designed our effort to take full use of external partners. We actively seek and support, including fund, people from multiple organizations to join us as committed collaborators. In this we use today's money and today's problem to help us diversify and strengthen for tomorrow. MSFC also considers the Applied Science work holistically. Each element is viewed as a step in a larger process. At a management level we can chose to emphasize or encourage certain areas which service long term goals. Thus, if we think work in a particular area should be developed, we can start with the smaller, less costly elements and grow.

Rickman, Doug↗
NASA NTRS2009

PrimeSupplier Cross-Program Impact Analysis and Supplier Stability Indicator Simulation Model

PrimeSupplier, a supplier cross-program and element-impact simulation model, with supplier solvency indicator (SSI), has been developed so that the shuttle program can see early indicators of supplier and product line stability, while identifying the various elements and/or programs that have a particular supplier or product designed into the system. The model calculates two categories of benchmarks to determine the SSI, with one category focusing on agency programmatic data and the other focusing on a supplier's financial liquidity. PrimeSupplier was developed to help NASA smoothly transition design, manufacturing, and repair operations from the Shuttle program to the Constellation program, without disruption in the industrial supply base.

Calluzzi, Michael↗
NASA NTRS2009

The New Weather Radar for America's Space Program in Florida: A Temperature Profile Adaptive Scan Strategy

A new weather radar is being acquired for use in support of America s space program at Cape Canaveral Air Force Station, NASA Kennedy Space Center, and Patrick AFB on the east coast of central Florida. This new radar replaces the modified WSR-74C at Patrick AFB that has been in use since 1984. The new radar is a Radtec TDR 43-250, which has Doppler and dual polarization capability. A new fixed scan strategy was designed to best support the space program. The fixed scan strategy represents a complex compromise between many competing factors and relies on climatological heights of various temperatures that are important for improved lightning forecasting and evaluation of Lightning Launch Commit Criteria (LCC), which are the weather rules to avoid lightning strikes to in-flight rockets. The 0 C to -20 C layer is vital since most generation of electric charge occurs within it and so it is critical in evaluating Lightning LCC and in forecasting lightning. These are two of the most important duties of 45 WS. While the fixed scan strategy that covers most of the climatological variation of the 0 C to -20 C levels with high resolution ensures that these critical temperatures are well covered most of the time, it also means that on any particular day the radar is spending precious time scanning at angles covering less important heights. The goal of this project is to develop a user-friendly, Interactive Data Language (IDL) computer program that will automatically generate optimized radar scan strategies that adapt to user input of the temperature profile and other important parameters. By using only the required scan angles output by the temperature profile adaptive scan strategy program, faster update times for volume scans and/or collection of more samples per gate for better data quality is possible, while maintaining high resolution at the critical temperature levels. The temperature profile adaptive technique will also take into account earth curvature and refraction when geo-locating the radar beam (i.e., beam height and arc distance), including non-standard refraction based on the user-input temperature profile. In addition to temperature profile adaptivity, this paper will also summarize the other requirements for this scan strategy program such as detection of low-level boundaries, detection of anvil clouds, reducing the Cone Of Silence, and allowing for times when deep convective clouds will not occur. The adaptive technique will be carefully compared to and benchmarked against the new fixed scan strategy. Specific environmental scenarios in which the adaptive scan strategy is able to optimize and improve coverage and resolution at critical heights, scan time, and/or sample numbers relative to the fixed scan strategy will be presented.

Carey, L. D.↗
NASA NTRS2006

Infrastructure for Rapid Development of Java GUI Programs

The Java Application Shell (JAS) is a software framework that accelerates the development of Java graphical-user-interface (GUI) application programs by enabling the reuse of common, proven GUI elements, as distinguished from writing custom code for GUI elements. JAS is a software infrastructure upon which Java interactive application programs and graphical user interfaces (GUIs) for those programs can be built as sets of plug-ins. JAS provides an application- programming interface that is extensible by application-specific plugins that describe and encapsulate both specifications of a GUI and application-specific functionality tied to the specified GUI elements. The desired GUI elements are specified in Extensible Markup Language (XML) descriptions instead of in compiled code. JAS reads and interprets these descriptions, then creates and configures a corresponding GUI from a standard set of generic, reusable GUI elements. These elements are then attached (again, according to the XML descriptions) to application-specific compiled code and scripts. An application program constructed by use of JAS as its core can be extended by writing new plug-ins and replacing existing plug-ins. Thus, JAS solves many problems that Java programmers generally solve anew for each project, thereby reducing development and testing time.

Jones, Jeremy↗
NASA NTRS2010

Innovative Partnerships Program Accomplishments: 2009-2010 at NASA's Kennedy Space Center

This document reports on the accomplishments of the Innovative Partnerships Program during the two years of 2009 and 2010. The mission of the Innovative Partnerships Program is to provide leveraged technology alternatives for mission directorates, programs, and projects through joint partnerships with industry, academia, government agencies, and national laboratories. As outlined in this accomplishments summary, the IPP at NASA's Kennedy Space Center achieves this mission via two interdependent goals: (1) Infusion: Bringing external technologies and expertise into Kennedy to benefit NASA missions, programs, and projects (2) Technology Transfer: Spinning out space program technologies to increase the benefits for the nation's economy and humanity

Makufka, David↗
NASA NTRS2010

Human Research Program Exploration Medical Capability

NASA s Human Research Program (HRP) conducts and coordinates research projects that provide human health and performance countermeasures, knowledge, technologies, and tools to enable safe, reliable, and productive human space exploration. The Program is divided into 6 major elements, which a) Provide the Program s knowledge and capabilities to conduct research, addressing the human health and performance risks. b) Advance the readiness levels of technology and countermeasures to the point of transfer to the customer programs and organizations. The National Space Biomedical Research Institute (NSBRI) is a partner with the HRP in developing a successful research program. 3

Barsten, Kristina↗
NASA NTRS2011

Spacecraft Testing Programs: Adding Value to the Systems Engineering Process

Testing has long been recognized as a critical component of spacecraft development activities - yet many major systems failures may have been prevented with more rigorous testing programs. The question is why is more testing not being conducted? Given unlimited resources, more testing would likely be included in a spacecraft development program. Striking the right balance between too much testing and not enough has been a long-term challenge for many industries. The objective of this paper is to discuss some of the barriers, enablers, and best practices for developing and sustaining a strong test program and testing team. This paper will also explore the testing decision factors used by managers; the varying attitudes toward testing; methods to develop strong test engineers; and the influence of behavior, culture and processes on testing programs. KEY WORDS: Risk, Integration and Test, Validation, Verification, Test Program Development

Britton, Keith J.↗
NASA NTRS2006

Program Predicts Performance of Optical Parametric Oscillators

A computer program predicts the performances of solid-state lasers that operate at wavelengths from ultraviolet through mid-infrared and that comprise various combinations of stable and unstable resonators, optical parametric oscillators (OPOs), and sum-frequency generators (SFGs), including second-harmonic generators (SHGs). The input to the program describes the signal, idler, and pump beams; the SFG and OPO crystals; and the laser geometry. The program calculates the electric fields of the idler, pump, and output beams at three locations (inside the laser resonator, just outside the input mirror, and just outside the output mirror) as functions of time for the duration of the pump beam. For each beam, the electric field is used to calculate the fluence at the output mirror, plus summary parameters that include the centroid location, the radius of curvature of the wavefront leaving through the output mirror, the location and size of the beam waist, and a quantity known, variously, as a propagation constant or beam-quality factor. The program provides a typical Windows interface for entering data and selecting files. The program can include as many as six plot windows, each containing four graphs.

Cross, Patricia L.↗
NASA NTRS2011

Constellation Program Lessons Learned: Detailed Lessons Learned - Volume 2

These lessons learned are part of a suite of hardware, software, test results, designs, knowledge base, and documentation that comprises the legacy of the Constellation Program. The context, summary information, and lessons learned are presented in a factual format, as known and described at the time. While our opinions might be discernable in the context, we have avoided all but factually sustainable statements. Statements should not be viewed as being either positive or negative; their value lies in what we did and what we learned that is worthy of passing on. The lessons include both "dos" and "don ts." In many cases, one person s "do" can be viewed as another person s "don t"; therefore, we have attempted to capture both perspectives when applicable and useful. While Volume I summarizes the views of those who managed the program, this Volume II encompasses the views at the working level, describing how the program challenges manifested in day-to-day activities. Here we see themes that were perhaps hinted at, but not completely addressed, in Volume I: unintended consequences of policies that worked well at higher levels but lacked proper implementation at the working level; long-term effects of the "generation gap" in human space flight development, the need to demonstrate early successes at the expense of thorough planning, and the consequences of problems and challenges not yet addressed because other problems and challenges were more immediate or manifest. Not all lessons learned have the benefit of being operationally vetted, since the program was cancelled shortly after Preliminary Design Review. We avoid making statements about operational consequences (with the exception of testing and test flights that did occur), but we do attempt to provide insight into how operational thinking influenced design and testing. The lessons have been formatted with a description, along with supporting information, a succinct statement of the lesson learned, and recommendations for future programs and projects that may be placed in similar circumstances.

Jennifer Rhatigan↗
NASA NTRS2011

The Creation of a CPU Timer for High Fidelity Programs

Using C and C++ programming languages, a tool was developed that measures the efficiency of a program by recording the amount of CPU time that various functions consume. By inserting the tool between lines of code in the program, one can receive a detailed report of the absolute and relative time consumption associated with each section. After adapting the generic tool for a high-fidelity launch vehicle simulation program called MAVERIC, the components of a frequently used function called "derivatives ( )" were measured. Out of the 34 sub-functions in "derivatives ( )", it was found that the top 8 sub-functions made up 83.1% of the total time spent. In order to decrease the overall run time of MAVERIC, a launch vehicle simulation program, a change was implemented in the sub-function "Event_Controller ( )". Reformatting "Event_Controller ( )" led to a 36.9% decrease in the total CPU time spent by that sub-function, and a 3.2% decrease in the total CPU time spent by the overarching function "derivatives ( )".

Dick, Aidan A.↗
NASA NTRS2005

Program Facilitates CMMI Appraisals

A computer program has been written to facilitate appraisals according to the methodology of Capability Maturity Model Integration (CMMI). [CMMI is a government/industry standard, maintained by the Software Engineering Institute at Carnegie Mellon University, for objectively assessing the engineering capability and maturity of an organization (especially, an organization that produces software)]. The program assists in preparation for a CMMI appraisal by providing drop-down lists suggesting required artifacts or evidence. It identifies process areas for which similar evidence is required and includes a copy feature that reduces or eliminates repetitive data entry. It generates reports to show the entire framework for reference, the appraisal artifacts to determine readiness for an appraisal, and lists of interviewees and questions to ask them during the appraisal. During an appraisal, the program provides screens for entering observations and ratings, and reviewing evidence provided thus far. Findings concerning strengths and weaknesses can be exported for use in a report or a graphical presentation. The program generates a chart showing capability level ratings of the organization. A context-sensitive Windows help system enables a novice to use the program and learn about the CMMI appraisal process.

Sweetser, Wesley↗
NASA NTRS2011

Final Report: Fire Prevention, Detection, and Suppression Project, Exploration Technology Development Program

The Fire Prevention, Detection, and Suppression (FPDS) project is a technology development effort within the Exploration Technology Development Program of the Exploration System Missions Directorate (ESMD) that addresses all aspects of fire safety aboard manned exploration systems. The overarching goal for work in the FPDS area is to develop technologies that will ensure crew health and safety on exploration missions by reducing the likelihood of a fire, or, if one does occur, minimizing the risk to the crew, mission, or system. This is accomplished by addressing the areas of (1) fire prevention and material flammability, (2) fire signatures and detection, and (3) fire suppression and response. This report describes the outcomes of this project from the formation of the Exploration Technology Development Program (ETDP) in October 2005 to September 31, 2010 when the Exploration Technology Development Program was replaced by the Enabling Technology Development and Demonstration Program. NASA s fire safety work will continue under this new program and will build upon the accomplishments described herein.

Ruff, Gary A.↗
NASA NTRS2011

NASA Water Resources Program

With increasing population pressure and water usage coupled with climate variability and change, water issues are being reported by numerous groups as the most critical environmental problems facing us in the 21st century. Competitive uses and the prevalence of river basins and aquifers that extend across boundaries engender political tensions between communities, stakeholders and countries. In addition to the numerous water availability issues, water quality related problems are seriously affecting human health and our environment. The potential crises and conflicts especially arise when water is competed among multiple uses. For example, urban areas, environmental and recreational uses, agriculture, and energy production compete for scarce resources, not only in the Western U.S. but throughout much of the U.S. and also in numerous parts of the world. Mitigating these conflicts and meeting water demands and needs requires using existing water resources more efficiently. The NASA Water Resources Program Element works to use NASA products and technology to address these critical water issues. The primary goal of the Water Resources is to facilitate application of NASA Earth science products as a routine use in integrated water resources management for the sustainable use of water. This also includes the extreme events of drought and floods and the adaptation to the impacts from climate change. NASA satellite and Earth system observations of water and related data provide a huge volume of valuable data in both near-real-time and extended back nearly 50 years about the Earth's land surface conditions such as precipitation, snow, soil moisture, water levels, land cover type, vegetation type, and health. NASA Water Resources Program works closely to use NASA and Earth science data with other U.S. government agencies, universities, and non-profit and private sector organizations both domestically and internationally. The NASA Water Resources Program organizes its projects under five functional themes. I) Streamflow and Flood Forecasting 2) Water Supply and Irrigation (includes evapotranspiration) 3) Drought 4) Water Quality 5) Climate and Water Resources. To maximize this activity NASA Water Resources Program works closely with other government agencies (e.g., the National Oceanic and Atmospheric Administration (NOAA); the U.S. Department of Agriculture (USDA); the U.S. Geological Survey (USGS); the Environmental Protection Agency (EPA), USAID, the Air Force Weather Agency (AFWA)), universities, non-profit national and international organizations, and the private sector. The NASA Water Resources program currently is funding 21 active projects under the functional themes (http://wmp.gsfc.nasa.gov & http://science.nasa.gov/earth-science/applied-sciences/).

Toll, David L.↗