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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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NASA NTRS1996

Transmembrane transport of peptide type compounds: prospects for oral delivery

Synthesis and delivery of potential therapeutic peptides and peptidomimetic compounds has been the focus of intense research over the last 10 years. While it is widely recognized that numerous limitations apply to oral delivery of peptides, some of the limiting factors have been addressed and their mechanisms elucidated, which has lead to promising strategies. This article will briefly summarize the challenges, results and current approaches of oral peptide delivery and give some insight on future strategies. The barriers determining peptide bioavailability after oral administration are intestinal membrane permability, size limitations, intestinal and hepatic metabolism and in some cases solubility limitations. Poor membrane permeabilities of hydrophilic peptides might be overcome by structurally modifying the compounds, thus increasing their membrane partition characteristics and/or their affinity to carrier proteins. Another approach is the site-specific delivery of the peptide to the most permeable parts of the intestine. The current view on size limitation for oral drug delivery has neglected partition considerations. Recent studies suggest that compounds with a molecular weight up to 4000 might be significantly absorbed, assuming appropriate partition behavior and stability. Metabolism, probably the most significant factor in the absorption fate of peptides, might be controlled by coadministration of competitive enzyme inhibitors, structural modifications and administration of the compound as a well absorbed prodrug that is converted into the therapeutically active agent after its absorption. For some peptides poor solubility might present a limitation to oral absorption, an issue that has been addressed by mechanistically defining and therefore improving formulation parameters. Effective oral peptide delivery requires further development in understanding these complex mechanisms in order to maximize the therapeutic potential of this class of compounds.

NASA Discipline Regulatory Physiology↗
NASA NTRS1999

Development and Implementation of a Load-Controlled Friction Stir Welder

Lockheed Martin Michoud Space Systems, under contract to NASA/MSFC, has developed and implemented a friction stir weld tool that uses the magnitude of the spindle axial load to control the weld process. This tool was used during the process development phase and the assembly of a full-scale External Tank barrel section. Both position and load transducers are incorporated into the welder. The control algorithm allows either the position or load transducer to provide the command variable in a closed loop system. Initially, the position transducer was used to actively control the weld process and the axial load on the spindle was monitored and collected via data acquisition hardware. As part of the process development, the axial load was implemented as the command variable in the closed loop. The spindle position is monitored and used to set limits on spindle travel. A zero set point algorithm has also been developed for establishing the spindle position at the start of the weld process. In its current state, the welder operates in a dual mode in which the position control is used to plunge the pin tool to a specified depth at the initiation of the weld. The load control is then used to control the weld process. This control algorithm has been used to assemble a 27.5-ft diameter, 2195-T8 barrel using hardware designed for NASA's Space Transportation System External Tank.

Loftus, Z.↗
NASA NTRS2010

26th Space Simulation Conference Proceedings. Environmental Testing: The Path Forward

Topics covered include: A Multifunctional Space Environment Simulation Facility for Accelerated Spacecraft Materials Testing; Exposure of Spacecraft Surface Coatings in a Simulated GEO Radiation Environment; Gravity-Offloading System for Large-Displacement Ground Testing of Spacecraft Mechanisms; Microscopic Shutters Controlled by cRIO in Sounding Rocket; Application of a Physics-Based Stabilization Criterion to Flight System Thermal Testing; Upgrade of a Thermal Vacuum Chamber for 20 Kelvin Operations; A New Approach to Improve the Uniformity of Solar Simulator; A Perfect Space Simulation Storm; A Planetary Environmental Simulator/Test Facility; Collimation Mirror Segment Refurbishment inside ESA s Large Space; Space Simulation of the CBERS 3 and 4 Satellite Thermal Model in the New Brazilian 6x8m Thermal Vacuum Chamber; The Certification of Environmental Chambers for Testing Flight Hardware; Space Systems Environmental Test Facility Database (SSETFD), Website Development Status; Wallops Flight Facility: Current and Future Test Capabilities for Suborbital and Orbital Projects; Force Limited Vibration Testing of JWST NIRSpec Instrument Using Strain Gages; Investigation of Acoustic Field Uniformity in Direct Field Acoustic Testing; Recent Developments in Direct Field Acoustic Testing; Assembly, Integration and Test Centre in Malaysia: Integration between Building Construction Works and Equipment Installation; Complex Ground Support Equipment for Satellite Thermal Vacuum Test; Effect of Charging Electron Exposure on 1064nm Transmission through Bare Sapphire Optics and SiO2 over HfO2 AR-Coated Sapphire Optics; Environmental Testing Activities and Capabilities for Turkish Space Industry; Integrated Circuit Reliability Simulation in Space Environments; Micrometeoroid Impacts and Optical Scatter in Space Environment; Overcoming Unintended Consequences of Ambient Pressure Thermal Cycling Environmental Tests; Performance and Functionality Improvements to Next Generation Thermal Vacuum Control System; Robotic Lunar Lander Development Project: Three-Dimensional Dynamic Stability Testing and Analysis; Thermal Physical Properties of Thermal Coatings for Spacecraft in Wide Range of Environmental Conditions: Experimental and Theoretical Study; Molecular Contamination Generated in Thermal Vacuum Chambers; Preventing Cross Contamination of Hardware in Thermal Vacuum Chambers; Towards Validation of Particulate Transport Code; Updated Trends in Materials' Outgassing Technology; Electrical Power and Data Acquisition Setup for the CBER 3 and 4 Satellite TBT; Method of Obtaining High Resolution Intrinsic Wire Boom Damping Parameters for Multi-Body Dynamics Simulations; and Thermal Vacuum Testing with Scalable Software Developed In-House.

Packard, Edward A.↗
NASA NTRS1973

Teleoperators and EVA for Shuttle missions

Review of the methods currently being contemplated for enabling the Space Shuttle to perform the Shuttle and payload support missions. Two general approaches to carrying out such activity are discussed - namely, the use of teleoperators and astronaut extravehicular activity (EVA). Detailed descriptions are given of an attached manipulator system (AMS) and a free-flying teleoperator (FFTO), noting the applications, capabilities, and limitations of each. The primary technology development areas for the AMS are in the areas of stabilization, structure, and manual control, while the technology areas of primary concern in the case of the FFTO include the manipulator-grappler system, the control system, the video system, and the mobility system. Four modes of EVA that are possible for the Shuttle are cited, noting the unlikelihood of direct applicability of EVA to payload deployment and retrieval and its feasibility for payload servicing and experiment support.

Malone, T. B.↗
NASA NTRS1977

Toward large space systems

The design of the Space Transportation System, consisting of the Space Shuttle, Spacelab, and upper stages, provides experience for the development of more advanced space systems. The next stage will involve space stations in low earth orbit with limited self-sufficiency, characterized by closed ecological environments, space-generated power, and perhaps the first use of space materials. The third phase would include manned geosynchronous space-station activity and a return to lunar operations. Easier access to space will encourage the use of more complex, maintenance-requiring satellites than those currently used. More advanced space systems could perform a wide range of public services such as electronic mail, personal and police communication, disaster control, earthquake detection/prediction, water availability indication, vehicle speed control, and burglar alarm/intrusion detection. Certain products, including integrated-circuit chips and some enzymes, can be processed to a higher degree of purity in space and might eventually be manufactured there. Hardware including dishes, booms, and planar surfaces necessary for advanced space systems and their development are discussed.

Daros, C. J.↗
NASA NTRS2014

A Computational Model for Simulating Spaceflight Induced Bone Remodeling

An overview of an initial development of a model of bone loss due to skeletal unloading in weight bearing sites is presented. The skeletal site chosen for the initial application of the model is the femoral neck region because hip fractures can be debilitating to the overall performance health of astronauts. The paper begins with the motivation for developing such a model of the time course of change in bone in order to understand the mechanism of bone demineralization experienced by astronauts in microgravity, to quantify the health risk, and to establish countermeasures. Following this, a general description of a mathematical formulation of the process of bone remodeling is discussed. Equations governing the rate of change of mineralized bone volume fraction and active osteoclast and osteoblast are illustrated. Some of the physiology of bone remodeling, the theory of how imbalance in remodeling can cause bone loss, and how the model attempts to capture this is discussed. The results of a preliminary validation analysis that was carried out are presented. The analysis compares a set of simulation results against bone loss data from control subjects who participated in two different bed rest studies. Finally, the paper concludes with outlining the current limitations and caveats of the model, and planned future work to enhance the state of the model.

Pennline, James A.↗
NASA NTRS2017

NASA Ames Institutional Scientific Collection (ISC)

NASA's current human space flight research is directed towards enabling human space exploration beyond Low Earth Orbit (LEO). The Space Flight Payload Projects; Rodent Research, Cell Science, and Microbial Labs, flown on the International Space Station (ISS), benefit both the global life sciences and commercial space communities. Verified data sets, science results, peer-reviewed publications, and returned biospecimens, collected and analyzed for flight and ground investigations, are all part of the knowledge base within NASA’s Human Exploration and Operations Mission Directorate’s Space Life and Physical Sciences Research and Applications (SLPSRA) Division, specifically the Human Research and Space Biology Programs. These data and biospecimens are made available through the public LSDA website. The Ames Institutional Scientific Collection (ISC), or ARC Biobank, stores flight and ground biospecimens from Space Shuttle and ISS programs. These specimens are curated and managed by the Ames Life Sciences Data Archive (ALSDA), an internal node of NASA's Life Sciences Data Archive (LSDA). The ARC Biolbank stores over 15,000 specimens from experiments dating from 1984 to present. Currently available specimens include tissues from the circulatory, digestive, endocrine, excretory, integumentary, muscular, neurosensory, reproductive, respiratory and skeletal systems. The most recent contributions include RNA, DNA and protein extracts from Rodent Research 1 and tissues from Rodent Research 4. NASA's biospecimen collection represents a unique and limited resource. The use of these biospecimens maximizes utilization and scientific return from these unique spaceflight payload and ground control research subjects. These biospecimens are harvested following complex, costly NASA research activities to meet primary scientific objectives. Once the primary scientific objectives have been met, the remaining specimens are made available to provide secondary opportunities for complementary studies or new investigations to broaden research without large expenditures of time or resources. Innovative ways of sharing this information ultimately advances the frontiers of human space exploration as well as scientific understanding of the effects of gravity on life on earth.

French, Alison J.↗
NASA NTRS2008

Current Issues in Human Spacecraft Thermal Control Technology

Efficient thermal management of Earth-orbiting human spacecraft, lunar transit spacecraft and landers, as well as a lunar habitat will require advanced thermal technology. These future spacecraft will require more sophisticated thermal control systems that can dissipate or reject greater heat loads at higher input heat fluxes while using fewer of the limited spacecraft mass, volume and power resources. The thermal control designs also must accommodate the harsh environments associated with these missions including dust and high sink temperatures. The lunar environment presents several challenges to the design and operation of active thermal control systems. During the Apollo program, landings were located and timed to occur at lunar twilight, resulting in a benign thermal environment. The long duration polar lunar bases that are foreseen in 15 years will see extremely cold thermal environments. Long sojourns remote from low-Earth orbit will require lightweight, but robust and reliable systems. Innovative thermal management components and systems are needed to accomplish the rejection of heat from lunar bases. Advances are required in the general areas of radiators, thermal control loops and equipment. Radiators on the Moon's poles must operate and survive in very cold environments. Also, the dusty environment of an active lunar base may require dust mitigation and removal techniques to maintain radiator performance over the long term.

Ungar, Eugene K.↗
NASA NTRS1997

Geotail Measurements Compared with the Motions of High-Latitude Auroral Boundaries during Two Substorms

Geotail plasma and field measurements at -95 R(sub E) are compared with extensive ground-based, near-Earth, and geosynchronous measurements to study relationships between auroral activity and magnetotail dynamics during the expansion phases of two substorms. The studied intervals are representative of intermittent, moderate activity. The behavior of the aurora and the observed effects at Geotail for both events are harmonized by the concept of the activation of near-Earth X lines (NEXL) after substorm onsets, with subsequent discharges of one or more plasmoids down the magnetotail. The plasmoids must be viewed as three-dimensional structures which are spatially limited in the dawn-dusk direction. Also, reconnection at the NEXL must proceed at variable rates on closed magnetic field lines for significant times before beginning to reconnect lobe flux. This implies that the plasma sheet in the near-Earth magnetotail is relatively thick in comparison with an embedded current sheet and that both the NEXL and distant X line can be active simultaneously. Until reconnection at the NEXL engages lobe flux, the distant X line maintains control of the poleward auroral boundary. If the NEXL remains active after reaching the lobe, the auroral boundary can move poleward explosively. The dynamics of high-latitude aurora in the midnight region thus provides a means for monitoring these processes and indicating when significant lobe flux reconnects at the NEXL.

Maynard, N. C.↗
NASA NTRS1996

Analysis of the access patterns at GSFC distributed active archive center

The Goddard Space Flight Center (GSFC) Distributed Active Archive Center (DAAC) has been operational for more than two years. Its mission is to support existing and pre Earth Observing System (EOS) Earth science datasets, facilitate the scientific research, and test Earth Observing System Data and Information System (EOSDIS) concepts. Over 550,000 files and documents have been archived, and more than six Terabytes have been distributed to the scientific community. Information about user request and file access patterns, and their impact on system loading, is needed to optimize current operations and to plan for future archives. To facilitate the management of daily activities, the GSFC DAAC has developed a data base system to track correspondence, requests, ingestion and distribution. In addition, several log files which record transactions on Unitree are maintained and periodically examined. This study identifies some of the users' requests and file access patterns at the GSFC DAAC during 1995. The analysis is limited to the subset of orders for which the data files are under the control of the Hierarchical Storage Management (HSM) Unitree. The results show that most of the data volume ordered was for two data products. The volume was also mostly made up of level 3 and 4 data and most of the volume was distributed on 8 mm and 4 mm tapes. In addition, most of the volume ordered was for deliveries in North America although there was a significant world-wide use. There was a wide range of request sizes in terms of volume and number of files ordered. On an average 78.6 files were ordered per request. Using the data managed by Unitree, several caching algorithms have been evaluated for both hit rate and the overhead ('cost') associated with the movement of data from near-line devices to disks. The algorithm called LRU/2 bin was found to be the best for this workload, but the STbin algorithm also worked well.

Johnson, Theodore↗
NASA NTRS1992

Automation and robotics considerations for a lunar base

An envisioned lunar outpost shares with other NASA missions many of the same criteria that have prompted the development of intelligent automation techniques with NASA. Because of increased radiation hazards, crew surface activities will probably be even more restricted than current extravehicular activity in low Earth orbit. Crew availability for routine and repetitive tasks will be at least as limited as that envisioned for the space station, particularly in the early phases of lunar development. Certain tasks are better suited to the untiring watchfulness of computers, such as the monitoring and diagnosis of multiple complex systems, and the perception and analysis of slowly developing faults in such systems. In addition, mounting costs and constrained budgets require that human resource requirements for ground control be minimized. This paper provides a glimpse of certain lunar base tasks as seen through the lens of automation and robotic (A&R) considerations. This can allow a more efficient focusing of research and development not only in A&R, but also in those technologies that will depend on A&R in the lunar environment.

Sliwa, Nancy E.↗
NASA NTRS2020

Control Demonstration of Multiple Doubly Fed Induction Motors for Hybrid Electric Propulsion

The Convergent Aeronautics Solutions (CAS) High Voltage Hybrid Electric Propulsion (HVHEP) activity was formulated to support the move into future hybrid-electric aircraft. The goal of this high-voltage activity is to develop a new alternating current (AC) power architecture to support the needs of higher efficiency and lower emissions aircraft. This proposed architecture will adopt the use of the doubly fed induction machine (DFIM) for propulsor drive motor application. The DFIMs are attractive for several reasons, including but not limited to, the ability to self-start, the ability to operate subsynchronously and supersynchronously, and the requirement for power converters rated at a fraction of those required in a corresponding direct current system, dependent on the range of operation. The focus of this report is based specifically on the presentation and analysis of a novel strategy, which allows for independent operation of multiple doubly fed induction motors from a common AC bus

David J Sadey↗
NASA NTRS1999

An Experimental and Numerical Study of Icing Effects on the Performance and Controllability of a Twin Engine Aircraft

In September 1997 the National Transportation Safety Board (NTSB) requested assistance from the NASA Lewis Research Center (LeRC) Icing Branch in the investigation of an aircraft accident that was suspected of being caused by ice contamination. In response to the request NASA agreed to perform an experimental and computational study. The main activities that NASA performed were LERC Icing Research Tunnel (IRT) testing to define ice shapes and 2-D Navier-Stokes analysis to determine the performance degradation that those ice shapes would have caused. An IRT test was conducted in January 1998. Most conditions for the test were based upon raw and derived data from the Flight Data Recorder (FDR) recovered from the accident and upon the current understanding of the Meteorological conditions near the accident. Using a two-dimensional Navier-Stokes code, the flow field and resultant lift and drag were calculated for the wing section with various ice shapes accreted in the IRT test. Before the final calculations could be performed extensive examinations of geometry smoothing and turbulence were conducted. The most significant finding of this effort is that several of the five-minute ice accretions generated in the IRT were found by the Navier-Stokes analysis to produce severe lift and drag degradation. The information generated by this study suggests a possible scenario for the kind of control upset recorded in the accident. Secondary findings were that the ice shapes accreted in the IRT were mostly limited to the protected pneumatic boot region of the wing and that during testing, activation of the pneumatic boots cleared most of the ice.

Reehorst, A.↗
NASA NTRS2006

Development and Testing of a Radial Halbach Magnetic Bearing

The NASA John H. Glenn Research Center has developed and tested a revolutionary Radial Halbach Magnetic Bearing. The objective of this work is to develop a viable non-contact magnetic bearing utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help reduce harmful emissions, reduce the Nation s dependence on fossil fuels and mitigate many of the concerns and limitations encountered in conventional axial bearings such as bearing wear, leaks, seals and friction loss. The Radial Halbach Magnetic Bearing is inherently stable and requires no active feedback control system or superconductivity as required in many magnetic bearing designs. The Radial Halbach Magnetic Bearing is useful for very high speed applications including turbines, instrumentation, medical applications, manufacturing equipment, and space power systems such as flywheels. Magnetic fields suspend and support a rotor assembly within a stator. Advanced technologies developed for particle accelerators, and currently under development for maglev trains and rocket launchers, served as the basis for this application. Experimental hardware was successfully designed and developed to validate the basic principles and analyses. The report concludes that the implementation of Radial Halbach Magnetic Bearings can provide significant improvements in rotational system performance and reliability.

Eichenberg, Dennis J.↗
NASA NTRS2006

Development and Testing of an Axial Halbach Magnetic Bearing

The NASA Glenn Research Center has developed and tested a revolutionary Axial Halbach Magnetic Bearing. The objective of this work is to develop a viable non-contact magnetic thrust bearing utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help to reduce harmful emissions, reduce the Nation s dependence on fossil fuels and mitigate many of the concerns and limitations encountered in conventional axial bearings such as bearing wear, leaks, seals and friction loss. The Axial Halbach Magnetic Bearing is inherently stable and requires no active feedback control system or superconductivity as required in many magnetic bearing designs. The Axial Halbach Magnetic Bearing is useful for very high speed applications including turbines, instrumentation, medical systems, computer memory systems, and space power systems such as flywheels. Magnetic fields suspend and support a rotor assembly within a stator. Advanced technologies developed for particle accelerators, and currently under development for maglev trains and rocket launchers, served as the basis for this application. Experimental hardware was successfully designed and developed to validate the basic principles and analyses. The report concludes that the implementation of Axial Halbach Magnetic Bearings can provide significant improvements in rotational system performance and reliability.

Eichenberg, Dennis J.↗
NASA NTRS2008

A Self Contained Method for Safe and Precise Lunar Landing

The return of humans to the Moon will require increased capability beyond that of the previous Apollo missions. Longer stay times and a greater flexibility with regards to landing locations are among the many improvements planned. A descent and landing system that can land the vehicle more accurately than Apollo with a greater ability to detect and avoid hazards is essential to the development of a Lunar Outpost, and also for increasing the number of potentially reachable Lunar Sortie locations. This descent and landing system should allow landings in more challenging terrain and provide more flexibility with regards to mission timing and lighting considerations, while maintaining safety as the top priority. The lunar landing system under development by the ALHAT (Autonomous precision Landing and Hazard detection Avoidance Technology) project is addressing this by providing terrain-relative navigation measurements to enhance global-scale precision, an onboard hazard-detection system to select safe landing locations, and an Autonomous GNC (Guidance, Navigation, and Control) capability to process these measurements and safely direct the vehicle to this landing location. This ALHAT landing system will enable safe and precise lunar landings without requiring lunar infrastructure in the form of navigation aids or a priori identified hazard-free landing locations. The safe landing capability provided by ALHAT uses onboard active sensing to detect hazards that are large enough to be a danger to the vehicle but too small to be detected from orbit, given currently planned orbital terrain resolution limits. Algorithms to interpret raw active sensor terrain data and generate hazard maps as well as identify safe sites and recalculate new trajectories to those sites are included as part of the ALHAT System. These improvements to descent and landing will help contribute to repeated safe and precise landings for a wide variety of terrain on the Moon.

Paschall, Stephen C., II↗
NASA NTRS1979

Problems and potentialities of cultured plant cells in retrospect and prospect

The past, present and expected future accomplishments and limitations of plant cell and tissue culture are reviewed. Consideration is given to the pioneering insights of Haberlandt in 1902, the development of culture techniques, and past work on cell division, cell and tissue growth and development, somatic embryogenesis, and metabolism and respiration. Current activity in culture media and technique development for plant regions, organs, tissues, cells, protoplasts, organelles and embryos, totipotency, somatic embryogenesis and clonal propagation under normal and space conditions, biochemical potentialities, and genetic engineering is surveyed. Prospects for the investigation of the induced control of somatic cell division, the division of isolated protoplasts, the improvement of haploid cell cultures, liquid cultures for somatic embryogenesis, and the genetic control of development are outlined.

Steward, F. C.↗
NASA NTRS1989

Neural networks in support of manned space

Many lobbyists in Washington have argued that artificial intelligence (AI) is an alternative to manned space activity. In actuality, this is the opposite of the truth, especially as regards artificial neural networks (ANNs), that form of AI which has the greatest hope of mimicking human abilities in learning, ability to interface with sensors and actuators, flexibility and balanced judgement. ANNs and their relation to expert systems (the more traditional form of AI), and the limitations of both technologies are briefly reviewed. A Few highlights of recent work on ANNs, including an NSF-sponsored workshop on ANNs for control applications are given. Current thinking on ANNs for use in certain key areas (the National Aerospace Plane, teleoperation, the control of large structures, fault diagnostics, and docking) which may be crucial to the long term future of man in space is discussed.

Werbos, Paul J.↗