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NASA NTRS2008

Guidance and Control Software Project Data - Volume 3: Verification Documents

The Guidance and Control Software (GCS) project was the last in a series of software reliability studies conducted at Langley Research Center between 1977 and 1994. The technical results of the GCS project were recorded after the experiment was completed. Some of the support documentation produced as part of the experiment, however, is serving an unexpected role far beyond its original project context. Some of the software used as part of the GCS project was developed to conform to the RTCA/DO-178B software standard, "Software Considerations in Airborne Systems and Equipment Certification," used in the civil aviation industry. That standard requires extensive documentation throughout the software development life cycle, including plans, software requirements, design and source code, verification cases and results, and configuration management and quality control data. The project documentation that includes this information is open for public scrutiny without the legal or safety implications associated with comparable data from an avionics manufacturer. This public availability has afforded an opportunity to use the GCS project documents for DO-178B training. This report provides a brief overview of the GCS project, describes the 4-volume set of documents and the role they are playing in training, and includes the verification documents from the GCS project. Volume 3 contains four appendices: A. Software Verification Cases and Procedures for the Guidance and Control Software Project; B. Software Verification Results for the Pluto Implementation of the Guidance and Control Software; C. Review Records for the Pluto Implementation of the Guidance and Control Software; and D. Test Results Logs for the Pluto Implementation of the Guidance and Control Software.

Hayhurst, Kelly J.↗
NASA NTRS2009

The Habitat Demonstration Unit Project

This paper will describe an overview of the NASA-led multi-center Habitat Demonstration Unit (HDU) Project. The HDU project is a technology-pull project that integrates technologies and innovations from numerous NASA centers. This project will be used to investigate and validate surface architectures, operations concepts, and requirements definition. The HDU project will be part of the 2010 Desert Research and Technologies Simulations (DRATS). The purpose of this project is to develop, integrate, test, and evaluate a HDU in the context of the mission architectures and surface operation concepts. This HDU is based on the Constellation Architecture Scenario 12.1 concept of a vertically oriented habitat module. A multi-center approach with be utilized to build, integrate, and test the HDU project through a shared collaborative effort of multiple NASA centers. This project is part of the strategic plan from the ESMD Directorate Integration Office (DIO) and the Lunar Surface Systems Project Office (LSSPO) to test surface elements in a surface analog environment which includes two Lunar Electric Rovers and the HDU during the 2010 analog field test. This paper will describe the overall objectives, its various configurations, strategic plan, and technology integration as it pertains to the 2010 and 2011 field analog tests.

Kennedy, Kriss J.↗
NASA NTRS2010

Project Management Using Modern Guidance, Navigation and Control Theory

The idea of control theory and its application to project management is not new, however literature on the topic and real-world applications is not as readily available and comprehensive in how all the principals of Guidance, Navigation and Control (GN&C) apply. This paper will address how the fundamental principals of modern GN&C Theory have been applied to NASA's Constellation Space Suit project and the results in the ability to manage the project within cost, schedule and budget. A s with physical systems, projects can be modeled and managed with the same guiding principles of GN&C as if it were a complex vehicle, system or software with time-varying processes, at times non-linear responses, multiple data inputs of varying accuracy and a range of operating points. With such systems the classic approach could be applied to small and well-defined projects; however with larger, multi-year projects involving multiple organizational structures, external influences and a multitude of diverse resources, then modern control theory is required to model and control the project. The fundamental principals of G N&C stated that a system is comprised of these basic core concepts: State, Behavior, Control system, Navigation system, Guidance and Planning Logic, Feedback systems. The state of a system is a definition of the aspects of the dynamics of the system that can change, such as position, velocity, acceleration, coordinate-based attitude, temperature, etc. The behavior of the system is more of what changes are possible rather than what can change, which is captured in the state of the system. The behavior of a system is captured in the system modeling and if properly done, will aid in accurate system performance prediction in the future. The Control system understands the state and behavior of the system and feedback systems to adjust the control inputs into the system. The Navigation system takes the multiple data inputs and based upon a priori knowledge of the input, will develop a statistical-based weighting of the input to determine where the system currently is located. Guidance and Planning logic of the system with the understanding of where it is (provided by the navigation system) will in turn determine where it needs to be and how to get there. Lastly, the system Feedback system is the right arm of the control system to allow it to affect change in the overall system and therefore it is critical to not only correctly identify the system feedback inputs but also the system response to the feedback inputs. And with any systems project it is critical that the objective of the system be clearly defined for not only planning but to be used to measure performance and to aid in the guidance of the system or project.

Hill, Terry↗
NASA NTRS2010

Project M: Scale Model of Lunar Landing Site of Apollo 17: Focus on Lighting Conditions and Analysis

This document captures the research and development of a scale model representation of the Apollo 17 landing site on the moon as part of the NASA INSPIRE program. Several key elements in this model were surface slope characteristics, crater sizes and locations, prominent rocks, and lighting conditions. This model supports development of Autonomous Landing and Hazard Avoidance Technology (ALHAT) and Project M for the GN&C Autonomous Flight Systems Branch. It will help project engineers visualize the landing site, and is housed in the building 16 Navigation Systems Technology Lab. The lead mentor was Dr. Timothy P. Crain. The purpose of this project was to develop an accurate scale representation of the Apollo 17 landing site on the moon. This was done on an 8'2.5"X10'1.375" reduced friction granite table, which can be restored to its previous condition if needed. The first step in this project was to research the best way to model and recreate the Apollo 17 landing site for the mockup. The project required a thorough plan, budget, and schedule, which was presented to the EG6 Branch for build approval. The final phase was to build the model. The project also required thorough research on the Apollo 17 landing site and the topography of the moon. This research was done on the internet and in person with Dean Eppler, a space scientist, from JSC KX. This data was used to analyze and calculate the scale of the mockup and the ratio of the sizes of the craters, ridges, etc. The final goal was to effectively communicate project status and demonstrate the multiple advantages of using our model. The conclusion of this project was that the mockup was completed as accurately as possible, and it successfully enables the Project M specialists to visualize and plan their goal on an accurate three dimensional surface representation.

Vanik, Christopher S.↗
NASA NTRS2011

Habitat Demonstration Unit Project Leadership and Management Strategies

This paper gives an overview of the National Aeronautics and Space Administration (NASA) led multi-center Habitat Demonstration Unit (HDU) project leadership and management strategies. The HDU project team constructed and tested an analog prototype lunar surface habitat/laboratory called the Pressurized Excursion Module (PEM) during 2010. The prototype unit subsystems were integrated in a short amount of time, utilizing a tiger team approach that brought together over 20 habitation-related technologies and innovations from a variety of NASA centers. This paper describes the leadership and management strategies as well as lessons learned pertaining to leading and managing a multi-center diverse team in a rapid prototype environment. The PEM configuration went from a paper design to an operational surface habitat demonstration unit in less than 12 months. The HDU project is part of the strategic plan from the Exploration Systems Mission Directorate (ESMD) Directorate Integration Office (DIO) and the Exploration Mission Systems Office (EMSO) to test destination elements in analog environments. The 2011 HDU-Deep Space Habitat (DSH) configuration will build upon the PEM work, and emphasize validity of crew operations (remote working and living), EVA operations, mission operations, logistics operations, and science operations that might be required in a deep space context for Near Earth Object (NEO) exploration mission architectures. The 2011 HDU-DSH will be field-tested during the 2011 Desert Research and Technologies Studies (DRaTS) field tests. The HDU project is a "technology-pull" project that integrates technologies and innovations from multiple NASA centers. This project will repurpose the HDU 2010 demo unit that was field tested in the 2010 DRaTS, adding habitation functionality to the prototype unit. This paper will describe the strategy of establishing a multi-center project management team that put in place the key multi-center leadership skills and disciplines to enable a successful tiger team approach. Advocacy was established with key stakeholders and NASA Headquarters (HQ) by defining a strategic vision, mission, goals and objectives for the project and team. As a technology-pull testbed capability the HDU project was able to collaborate and leverage the Exploration Technology Development Program (ETDP) and individual NASA center investments which capitalized on their respective center core competencies and skills. This approach enable the leveraging of over $7.5m of value to create an operational habitat demonstration unit 2010 PEM configuration.

Kennedy, Kriss J.↗
NASA NTRS2015

Improving Climate Projections Using "Intelligent" Ensembles

Recent changes in the climate system have led to growing concern, especially in communities which are highly vulnerable to resource shortages and weather extremes. There is an urgent need for better climate information to develop solutions and strategies for adapting to a changing climate. Climate models provide excellent tools for studying the current state of climate and making future projections. However, these models are subject to biases created by structural uncertainties. Performance metrics-or the systematic determination of model biases-succinctly quantify aspects of climate model behavior. Efforts to standardize climate model experiments and collect simulation data-such as the Coupled Model Intercomparison Project (CMIP)-provide the means to directly compare and assess model performance. Performance metrics have been used to show that some models reproduce present-day climate better than others. Simulation data from multiple models are often used to add value to projections by creating a consensus projection from the model ensemble, in which each model is given an equal weight. It has been shown that the ensemble mean generally outperforms any single model. It is possible to use unequal weights to produce ensemble means, in which models are weighted based on performance (called "intelligent" ensembles). Can performance metrics be used to improve climate projections? Previous work introduced a framework for comparing the utility of model performance metrics, showing that the best metrics are related to the variance of top-of-atmosphere outgoing longwave radiation. These metrics improve present-day climate simulations of Earth's energy budget using the "intelligent" ensemble method. The current project identifies several approaches for testing whether performance metrics can be applied to future simulations to create "intelligent" ensemble-mean climate projections. It is shown that certain performance metrics test key climate processes in the models, and that these metrics can be used to evaluate model quality in both current and future climate states. This information will be used to produce new consensus projections and provide communities with improved climate projections for urgent decision-making.

Baker, Noel C.↗
NASA NTRS2015

Improving Climate Projections Using "Intelligent" Ensembles

Recent changes in the climate system have led to growing concern, especially in communities which are highly vulnerable to resource shortages and weather extremes. There is an urgent need for better climate information to develop solutions and strategies for adapting to a changing climate. Climate models provide excellent tools for studying the current state of climate and making future projections. However, these models are subject to biases created by structural uncertainties. Performance metrics-or the systematic determination of model biases-succinctly quantify aspects of climate model behavior. Efforts to standardize climate model experiments and collect simulation data-such as the Coupled Model Intercomparison Project (CMIP)-provide the means to directly compare and assess model performance. Performance metrics have been used to show that some models reproduce present-day climate better than others. Simulation data from multiple models are often used to add value to projections by creating a consensus projection from the model ensemble, in which each model is given an equal weight. It has been shown that the ensemble mean generally outperforms any single model. It is possible to use unequal weights to produce ensemble means, in which models are weighted based on performance (called "intelligent" ensembles). Can performance metrics be used to improve climate projections? Previous work introduced a framework for comparing the utility of model performance metrics, showing that the best metrics are related to the variance of top-of-atmosphere outgoing longwave radiation. These metrics improve present-day climate simulations of Earth's energy budget using the "intelligent" ensemble method. The current project identifies several approaches for testing whether performance metrics can be applied to future simulations to create "intelligent" ensemble-mean climate projections. It is shown that certain performance metrics test key climate processes in the models, and that these metrics can be used to evaluate model quality in both current and future climate states. This information will be used to produce new consensus projections and provide communities with improved climate projections for urgent decision-making.

Baker, Noel C.↗
NASA NTRS2016

Advanced EVA Suit Camera System Development Project

The National Aeronautics and Space Administration (NASA) at the Johnson Space Center (JSC) is developing a new extra-vehicular activity (EVA) suit known as the Advanced EVA Z2 Suit. All of the improvements to the EVA Suit provide the opportunity to update the technology of the video imagery. My summer internship project involved improving the video streaming capabilities of the cameras that will be used on the Z2 Suit for data acquisition. To accomplish this, I familiarized myself with the architecture of the camera that is currently being tested to be able to make improvements on the design. Because there is a lot of benefit to saving space, power, and weight on the EVA suit, my job was to use Altium Design to start designing a much smaller and simplified interface board for the camera's microprocessor and external components. This involved checking datasheets of various components and checking signal connections to ensure that this architecture could be used for both the Z2 suit and potentially other future projects. The Orion spacecraft is a specific project that may benefit from this condensed camera interface design. The camera's physical placement on the suit also needed to be determined and tested so that image resolution can be maximized. Many of the options of the camera placement may be tested along with other future suit testing. There are multiple teams that work on different parts of the suit, so the camera's placement could directly affect their research or design. For this reason, a big part of my project was initiating contact with other branches and setting up multiple meetings to learn more about the pros and cons of the potential camera placements we are analyzing. Collaboration with the multiple teams working on the Advanced EVA Z2 Suit is absolutely necessary and these comparisons will be used as further progress is made for the overall suit design. This prototype will not be finished in time for the scheduled Z2 Suit testing, so my time was also spent creating a case for the original interface board that is already being used. This design is being done by use of Creo 2. Due to time constraints, I may not be able to complete the 3-D printing portion of this design, but I was able to use my knowledge of the interface board and Altium Design to help in the task. As a side project, I assisted another intern in selecting and programming a microprocessor to control linear actuators. These linear actuators will be used to move various increments of polyethylene for controlled radiation testing. For this, we began the software portion of the project using the Arduino's coding environment to control an Arduino Due and H-Bridge components. Along with the obvious learning of computer programs such as Altium Design and Creo 2, I also acquired more skills with networking and collaborating with others, being able to multi-task because of responsibilities to work on various projects, and how to set realistic goals in the work place. Like many internship projects, this project will be continued and improved, so I also had the chance to improve my organization and communication skills as I documented all of my meetings and research. As a result of my internship at JSC, I desire to continue a career with NASA, whether that be through another internship or possibly a co-op. I am excited to return to my university and continue my education in electrical engineering because of all of my experiences at JSC.

Mock, Kyla↗
NASA NTRS2018

Collaborative Systems Engineering in the Ascent Abort-2 Crew Module/Separation Ring Project

Generally speaking, systems engineering (SE) tool-sets face a dilemma balancing power and accessibility. High-powered SE tools (MagicDraw, Cradle, Core, etc.) tend to be specialized and are available only to highly trained Systems Engineers, and/or through the use of a 'back room' developer team making the output products available to the broader team. On the other hand, highly accessible tools (MS Word, Excel, etc.) do not have the power to implement SE in a rigorous manner. NASA has to test all aspects of the new human-rated Orion Multi-Purpose Crew Vehicle spacecraft prior to its first crewed mission. The test program includes uncrewed launch abort flight tests to demonstrate the capability to save the crew in the event that a launch failure occurs. Orion's second abort flight test will be a low-altitude flight test known as "Ascent Abort 2 (AA-2)." This test is currently scheduled to be carried out at Cape Canaveral Air Force Station's Space Launch Complex 46 (SLC-46) in Florida in 2019. NASA's in-house AA-2 Crew Module and Separation Ring (CSR) Team is producing the crew module and separation ring. Operating jointly as both an Advanced Exploration Systems (AES) Project and an Orion Project, the CSR project charter includes development of innovative, streamlined and generally more efficient practices for creation of flight hardware and software. One result of this tasking has been development of a collaborative and data-centric systems engineering environment within the team's shared web environment (Microsoft SharePoint). Through the use of built-in, 'out of the box capabilities' present in MS SharePoint, the CSR Systems Engineering team has created (with some limited developer support) a data-centric architecture for the project's SE implementation, including functional and interface analysis, requirements development and management, risk management, verification planning and management, test results, and end item management. Data elements are linked between data structures so as to define and control relationships between item types, link requirements to parents and children, and link tests to the requirements that they verify. The overall project team integration is increased by also linking SE content to project management content over the project life cycle, including team communication, action items, configuration management, decisional and meeting materials, and life cycle reviews. This presentation will provide an overview of the collaborative SE environment, showing how it provides the power for a number of SE tasks while still providing the accessibility and transparency to allow the full project team to collaborate and succeed. Given the project phase, we'll be able to present a nearly full lifecycle discussion, from concept through verification and approaching delivery.

Systems Engineering environments↗
NASA NTRS2016

Implementing Effective Mission Systems Engineering Practices During Early Project Formulation Phases

Developing and implementing a plan for a NASA space mission can be a complicated process. The needs, goals, and objectives of any proposed mission or technology must be assessed early in the Project Life Cycle. The key to successful development of a space mission or flight project is the inclusion of systems engineering in early project formulation, namely during Pre-phase A, Phase A, and Phase B of the NASA Project Life Cycle. When a space mission or new technology is in pre-development, or "pre-Formulation", feasibility must be determined based on cost, schedule, and risk. Inclusion of system engineering during project formulation is key because in addition to assessing feasibility, design concepts are developed and alternatives to design concepts are evaluated. Lack of systems engineering involvement early in the project formulation can result in increased risks later in the implementation and operations phases of the project. One proven method for effective systems engineering practice during the pre-Formulation Phase is the use of a mission conceptual design or technology development laboratory, such as the Mission Design Lab (MDL) at NASA's Goddard Space Flight Center (GSFC). This paper will review the engineering process practiced routinely in the MDL for successful mission or project development during the pre-Formulation Phase.

Processes↗
NASA NTRS1971

System Definition Phase and Acquisition Phase Project Plan for Small Astronomy Satellite SAS-D

This Project Plan for the Small Astronomy Satellite (SAS-D) is Goddard Space Flight Center's plan for accomplishing the project. It is issued in compliance with NASA Handbook NHB 7121.2 and NMI 7120.1, dated May 4, 1970, Subject: Approval and Implementation of Office of Space Science and Applications (OSSA) Research and Development (R&D) Projects. The Project Plan, as approved by GSFC executive management and NASA Headquarters, is the project manager's charter and defines his specific plan of action. System definition phase activities of the SAS-D Project will be a continuation of the analytical work that established the overall feasibility of the project. The system concept derived from that analytical work is defined in the Phase A (Mission Definition Phase) technical report. System definition phase activities will include detailed engineering analysis and preliminary breadboarding necessary to establish a single project approach from the feasible approaches. This document will be revised at the end of the system definition phase to provide greater detail on acquisition phase planning and to specify a specific system design.

Donald A Krueger↗
NASA NTRS1971

Modular space station Phase B extension preliminary performance specification. Volume 2: Project

The four systems of the modular space station project are described, and the interfaces between this project and the shuttle project, the tracking and data relay satellite project, and an arbitrarily defined experiment project are defined. The experiment project was synthesized from internal experiments, detached research and application modules, and attached research and application modules to derive a set of interface requirements which will support multiple combinations of these elements expected during the modular space station mission. The modular space station project element defines a 6-man orbital program capable of growth to a 12-man orbital program capability. The modular space station project element specification defines the modular space station system, the premission operations support system, the mission operations support system, and the cargo module system and their interfaces.

Source record↗
NASA NTRS1993

Design of components for the NASA OCEAN project

The goal of the Fall 1993 semester of the EGM 4000 class was to design, fabricate, and test components for the 'Ocean CELSS Experimental Analog NASA' Project (OCEAN Project) and to aid in the future development of NASA's Controlled Ecological Life Support System (CELSS). The OCEAN project's specific aims are to place a human, Mr. Dennis Chamberland from NASA's Life Science Division of Research, into an underwater habitat off the shore of Key Largo, FL for three months. During his stay, he will monitor the hydroponic growth of food crops and evaluate the conditions necessary to have a successful harvest of edible food. The specific designs chosen to contribute to the OCEAN project by the EGM 4000 class are in the areas of hydroponic habitat monitoring, human health monitoring, and production of blue/green algae. The hydroponic monitoring system focused on monitoring the environment of the plants. This included the continuous sensing of the atmospheric and hydroponic nutrient solution temperatures. Methods for monitoring the continuous flow of the hydroponic nutrient solution across the plants and the continuous supply of power for these sensing devices were also incorporated into the design system. The human health monitoring system concentrated on continuously monitoring various concerns of the occupant in the underwater living habitat of the OCEAN project. These concerns included monitoring the enclosed environment for dangerous levels of carbon monoxide and smoke, high temperatures from fire, and the ceasing of the continuous airflow into the habitat. The blue/green algae project emphasized both the production and harvest of a future source of food. This project did not interact with any part of the OCEAN project. Rather, it was used to show the possibility of growing this kind of algae as a supplemental food source inside a controlled ecological life support system.

Wright, Jenna↗
NASA NTRS1993

Support of an Active Science Project by a Large Information System: Lessons for the EOS Era

The ability of large information systems to support the changing data requirements of active science projects is being tested in a NASA collaborative study. This paper briefly profiles both the active science project and the large information system involved in this effort and offers some observations about the effectiveness of the project support. This is followed by lessons that are important for those participating in large information systems that need to support active science projects or that make available the valuable data produced by these projects. We learned in this work that it is difficult for a large information system focused on long term data management to satisfy the requirements of an on-going science project. For example, in order to provide the best service, it is important for all information system staff to keep focused on the needs and constraints of the scientists in the development of appropriate services. If the lessons learned in this and other science support experiences are not applied by those involved with large information systems of the EOS (Earth Observing System) era, then the final data products produced by future science projects may not be robust or of high quality, thereby making the conduct of the project science less efficacious and reducing the value of these unique suites of data for future research.

Angelici, Gary L.↗
NASA NTRS1998

Aeronautics and Aviation Science: Careers and Opportunities Project

The National Aeronautics and Space Administration funded project, Aeronautics and Aviation Science: Careers and Opportunities has been in operation since July, 1995. This project operated as a collaboration with Massachusetts Corporation for Educational Telecommunications, the Federal Aviation Administration, Bridgewater State College and four targeted "core sites" in the greater Boston area. In its first and second years, a video series on aeronautics and aviation science was developed and broadcast via "live, interactive" satellite feed. Accompanying teacher and student supplementary instructional materials for grades 6-9 were produced and disseminated by the Massachusetts Corporation for Educational Telecommunications (MCET). In the MCET grant application it states that project Take Off! in its initial phase would recruit and train teachers at "core" sites in the greater Boston area, as well as opening participation to other on-line users of MCET's satellite feeds. "Core site" classrooms would become equipped so that teachers and students might become engaged in an interactive format which aimed at not only involving the students during the "live" broadcast of the instructional video series, but which would encourage participation in electronic information gathering and sharing among participants. As a Take Off! project goal, four schools with a higher than average proportion of minority and underrepresented youth were invited to become involved with the project to give these students the opportunity to consider career exploration and development in the field of science aviation and aeronautics. The four sites chosen to participate in this project were: East Boston High School, Dorchester High School, Randolph Junior-Senior High School and Malden High School. In year 3 Dorchester was unable to continue to fully participate and exited out. Danvers was added to the "core site" list in year 3. In consideration of Goals 2000, the National Science Foundation standards for quality of teaching, and an educational agenda that promotes high standards for all students, Aeronautics and Aviation Science: Careers and Opportunities had as its aim to deliver products to schools, both in and outside the project sites, which attempt to incorporate multi-disciplined approaches in the presentation of a curriculum which would be appropriate in any classroom, while also aiming to appeal to young women and minorities. The curriculum was developed to provide students with fundamentals of aeronautics and aviation science. The curriculum also encouraged involving students and teachers in research projects, and further information gathering via electronic bulletin boards and internet capabilities. Though not entirely prescriptive, the curriculum was designed to guide teachers through recommended activities to supplement MCET's live telecast video presentations. Classroom teachers were encouraged to invite local pilots, meteorologists, and others from the field of aviation and aeronautics, particularly women and minorities to visit schools and to field questions from the students.

Texter, P. Cardie↗
NASA NTRS2003

Academy Sharing Knowledge (ASK). The NASA Source for Project Management Magazine, Volume 11, March 2003

APPL is a research-based organization that serves NASA program and project managers, as well as project teams, at every level of development. In 1997, APPL was created from an earlier program to underscore the importance that NASA places on project management and project teams through a wide variety of products and services, including knowledge sharing, classroom and online courses, career development guidance, performance support, university partnerships, and advanced technology tools. ASK Magazine grew out of APPL's Knowledge Sharing Initiative. The stories that appear in ASK are written by the 'best of the best' project managers, primarily from NASA, but also from other government agencies and industry. Contributors to this issue include: Teresa Bailey, a librarian at the Jet Propulsion Laboratory, Roy Malone, Deputy Director in the Safety and Mission Assurance (S&MA) Office at the NASA Marshall Space Flight Center (MSFC), W. Scott Cameron, Capital Systems Manager for the Food and Beverage Global Business Unit of Procter and Gamble, Ray Morgan, recent retiree as Vice President of AeroVironment, Inc., Marty Davis, Program Manager of the Geostationary Operational Environmental Satellite (GOES) at the NASA Goddard Space Flight Center (GSFC) in Greenbelt, Maryland, Todd Post, editor of ASK Magazine, and works for EduTech Ltd. in Silver Spring, Maryland, Dr. Owen Gadeken, professor of Engineering Management at the Defense Acquisition University, Ken Schwer, currently the Project Manager of Solar Dynamics Observatory, Dr. Edward Hoffmwan, Director of the NASA Academy of Program and Project Leadership, Frank Snow, a member of the NASA Explorer Program at Goddard Space Flight Center since 1992, Dr. Alexander Laufer, Editor-in-Chief of ASK Magazine and a member of the Advisory Board of the NASA Academy of Program and Project Leadership, Judy Stokley, presently Air Force Program Executive Officer for Weapons in Washington, D.C. and Terry Little, Director of the Kinetic Energy Boost Office of the Missile Defense Agency.

Source record↗
NASA NTRS1996

Differential central projections of vestibular afferents in pigeons

The question of whether a differential distribution of vestibular afferent information to central nuclear neurons is present in pigeons was studied using neural tracer compounds. Discrete tracing of afferent fibers innervating the individual semicircular canal and otolith organs was produced by sectioning individual branches of the vestibular nerve that innervate the different receptor organs and applying crystals of horseradish peroxidase, or a horseradish peroxidase/cholera toxin mixture, or a biocytin compound for neuronal uptake and transport. Afferent fibers and their terminal distributions within the brainstem and cerebellum were visualized subsequently. Discrete areas in the pigeon central nervous system that receive primary vestibular input include the superior, dorsal lateral, ventral lateral, medial, descending, and tangential vestibular nuclei; the A and B groups; the intermediate, medial, and lateral cerebellar nuclei; and the nodulus, the uvula, and the paraflocculus. Generally, the vertical canal afferents projected heavily to medial regions in the superior and descending vestibular nuclei as well as the A group. Vertical canal projections to the medial and lateral vestibular nuclei were observed but were less prominent. Horizontal canal projections to the superior and descending vestibular nuclei were much more centrally located than those of the vertical canals. A more substantial projection to the medial and lateral vestibular nuclei was seen with horizontal canal afferents compared to vertical canal fibers. Afferents innervating the utricle and saccule terminated generally in the lateral regions of all vestibular nuclei in areas that were separate from the projections of the semicircular canals. In addition, utricular fibers projected to regions in the vestibular nuclei that overlapped with the horizontal semicircular canal terminal fields, whereas saccular afferents projected to regions that received vertical canal fiber terminations. Lagenar afferents projected throughout the cochlear nuclei, to the dorsolateral regions of the cerebellar nuclei, and to lateral regions of the superior, lateral, medial, and descending vestibular nuclei.

NASA Discipline Neuroscience↗
NASA NTRS1995

Morphology and kainate-receptor immunoreactivity of identified neurons within the entorhinal cortex projecting to superior temporal sulcus in the cynomolgus monkey

Projections of the entorhinal cortex to the hippocampus are well known from the classical studies of Cajal (Ramon y Cajal, 1904) and Lorente de No (1933). Projections from the entorhinal cortex to neocortical areas are less well understood. Such connectivity is likely to underlie the consolidation of long-term declarative memory in neocortical sites. In the present study, a projection arising in layer V of the entorhinal cortex and terminating in a polymodal association area of the superior temporal gyrus has been identified with the use of retrograde tracing. The dendritic arbors of neurons giving rise to this projection were further investigated by cell filling and confocal microscopy with computer reconstruction. This analysis demonstrated that the dendritic arbor of identified projection neurons was largely confined to layer V, with the exception of a solitary, simple apical dendrite occasionally ascending to superficial laminae but often confined to the lamina dissecans (layer IV). Finally, immunoreactivity for glutamate-receptor subunit proteins GluR 5/6/7 of the dendritic arbor of identified entorhinal projection neurons was examined. The solitary apical dendrite of identified entorhinal projection neurons was prominently immunolabeled for GluR 5/6/7, as was the dendritic arbor of basilar dendrites of these neurons. The restriction of the large bulk of the dendritic arbor of identified entorhinal projection neurons to layer V implies that these neurons are likely to be heavily influenced by hippocampal output arriving in the deep layers of the entorhinal cortex. Immunoreactivity for GluR 5/6/7 throughout the dendritic arbor of such neurons indicates that this class of glutamate receptor is in a position to play a prominent role in mediating excitatory neurotransmission within hippocampal-entorhinal circuits.

NASA Discipline Neuroscience↗