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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 NTRSDate not supplied

NTAC Augmented Nuclear and Advanced Propulsion

Currently, there are two types of nuclear propulsion: Nuclear Thermal Propulsion (NTP) and Nuclear Electric Propulsion (NEP). Common to both types, a nuclear reactor generates heat energy to raise the temperature of propellant, or the generated heat energy is converted into electric power. The electricity generated powers propulsion systems, such as a Hall thruster, magnetoplasma dynamic (MPD) thruster, or variable specific impulse magnetoplasma rocket (VASIMR). Customarily, only the thermal energy output from nuclear reaction is considered for NTP and NEP systems. However, the nuclear fission reaction can also generate ~7 MeV of prompt gamma rays. Therefore, most designers of NTP and NEP systems incorporate safety features to shield against this radiation. An optimized design approach would be to integrate a Nuclear Thermionic Avalanche Cell (NTAC) within the NTP or NEP structure for converting this radiation energy into additional electric power, while also shielding gamma rays. Consequently, this study addresses several combinations of NTP and NEP structures with NTAC devices in order to achieve that goal.

NTAC↗
NASA NTRS1979

Planetary mission requirements, technology and design considerations for a solar electric propulsion stage

High energy planetary missions such as comet rendezvous, Saturn orbiter and asteroid rendezvous require development of a Solar Electric Propulsion Stage (SEPS) for augmentation of the Shuttle-IUS. Performance and functional requirements placed on the SEPS are presented. These requirements will be used in evolution of the SEPS design, which must be highly interactive with both the spacecraft and the mission design. Previous design studies have identified critical SEPS technology areas and some specific design solutions which are also presented in the paper.

Cork, M. J.↗
NASA NTRS1981

Space platforms - A cost effective evolution of Spacelab operation

The capabilities added to the Shuttle/Spacelab configuration by the addition of the Power Extension Package (PEP), the Power System (PS), and the Science and Applications Space Platforms (SASP) are reviewed with an emphasis on SASP. SASP are intended for placement in orbit by the Shuttle to test new instruments and systems, for clustering of instrumentation, and for servicing, refurbishment, repair, or augmentation by the Shuttle. The PEP permits extended stays in orbit (30 days), and the PS is an orbital solar array and energy storage system acting as a free flying spacecraft. The Shuttle can deliver payloads to the PS or attach to it for extension of the Spacelab operations. Applications of SASP for long term space-based biological experiments are outlined, and the fact that SASP do not increase the required Shuttle in-orbit time is stressed.

Stofan, A. J.↗
NASA NTRS1990

Two dimensional tethered satellite attitude dynamics

This paper discusses a simplified dynamical model of two-dimensional tethered satellite attitude motion (coning). The tether is assumed massless, inextensible, and long relative to the satellite dimension, and has no flexural rigidity. The satellite is assumed rigid, is constrained to planar motion, and the model includes a tension augmentation thruster. Problem formulation results in one second order differential equation which has one integral of motion that is not the system energy. Results of the analysis include methods of changing satellite rotational energy, the effects of changing the tether tension, and frequency/amplitude information.

Humble, Ronald W.↗
NASA NTRS1940

The Torsion of Box Beams with One Side Lacking

The torsion of box beams of rectangular section, the edges of which are strengthened by flanges, and of which one side is lacking, is analyzed by the energy method. The torsional stresses are generally taken up by the bending of the two parallel walls, the rigidity of which is augmented by the third wall. The result was checked experimentally on duralumin and plywood boxes. The torsion recorded was 10 to 30 percent less than that given by the calculation, owing to self-stiffening.

Cambilargiu, E↗
NASA NTRS2019

The Seismic Experiment for Interior Structure (SEIS): Experiment Data Distribution

The six sensors of SEIS (The Seismic Experiment for Interior Structure) [- one of three primary instruments on NASA's Mars Lander Insight] cover a broad range of the seismic bandwidth, from 0.01 hertz to 50 hertz, with possible extension to longer periods. Data are transmitted in the form of three continuous VBB (Very Broad-Band) components at 2 samples per second (sps), an estimation of the short period (SP) energy content from the SP at 1 sps, and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams are augmented by requested event data with sample rates from 20 to 100 sps. SEIS data products are downlinked from the spacecraft in raw CCSDS (Consultative Committee for Space Data Systems) packets and converted to both the Standard for the Exchange of Earthquake Data (SEED) format files and ASCII tables (GeoCSV) for analysis and archiving. Metadata are available in dataless SEED and StionXML. Time series data (waveforms) are available in miniseed and GeoCSV. Data are distributed according to FDSN (Federation of Digital Seismograph Networks - http://www.fdsn.org) formats and interfaces. Wind, pressure and temperature data from the Auxiliary Payload Sensor Suite (APSS) will also be available in SEED format, and can be used for decorrelation and diagnostic purposes on SEIS.

Pardo, Constanza↗
NASA NTRS2011

Real-Time CME Forecasting Using HMI Active-Region Magnetograms and Flare History

We have recently developed a method of predicting an active region s probability of producing a CME, an X-class Flare, an M-class Flare, or a Solar Energetic Particle Event from a free-energy proxy measured from SOHO/MDI line-of-sight magnetograms. This year we have added three major improvements to our forecast tool: 1) Transition from MDI magnetogram to SDO/HMI magnetogram allowing us near-real-time forecasts, 2) Automation of acquisition and measurement of HMI magnetograms giving us near-real-time forecasts (no older than 2 hours), and 3) Determination of how to improve forecast by using the active region s previous flare history in combination with its free-energy proxy. HMI was turned on in May 2010 and MDI was turned off in April 2011. Using the overlap period, we have calibrated HMI to yield what MDI would measure. This is important since the value of the free-energy proxy used for our forecast is resolution dependent, and the forecasts are made from results of a 1996-2004 database of MDI observations. With near-real-time magnetograms from HMI, near-real-time forecasts are now possible. We have augmented the code so that it continually acquires and measures new magnetograms as they become available online, and updates the whole-sun forecast from the coming day. The next planned improvement is to use an active region s previous flare history, in conjunction with its free-energy proxy, to forecast the active region s event rate. It has long been known that active regions that have produced flares in the past are likely to produce flares in the future, and that active regions that are nonpotential (have large free-energy) are more likely to produce flares in the future. This year we have determined that persistence of flaring is not just a reflection of an active region s free energy. In other words, after controlling for free energy, we have found that active regions that have flared recently are more likely to flare in the future.

Falconer, David↗
NASA NTRS1974

Turbulence flight director analysis and preliminary simulation

A control column and trottle flight director display system is synthesized for use during flight through severe turbulence. The column system is designed to minimize airspeed excursions without overdriving attitude. The throttle system is designed to augment the airspeed regulation and provide an indication of the trim thrust required for any desired flight path angle. Together they form an energy management system to provide harmonious display indications of current aircraft motions and required corrective action, minimize gust upset tendencies, minimize unsafe aircraft excursions, and maintain satisfactory ride qualities. A preliminary fixed-base piloted simulation verified the analysis and provided a shakedown for a more sophisticated moving-base simulation to be accomplished next. This preliminary simulation utilized a flight scenario concept combining piloting tasks, random turbulence, and discrete gusts to create a high but realistic pilot workload conducive to pilot error and potential upset. The turbulence director (energy management) system significantly reduced pilot workload and minimized unsafe aircraft excursions.

Johnson, D. E.↗
NASA NTRS1980

Modeling and Analysis of Power Processing Systems (MAPPS). Volume 1: Technical report

Computer aided design and analysis techniques were applied to power processing equipment. Topics covered include: (1) discrete time domain analysis of switching regulators for performance analysis; (2) design optimization of power converters using augmented Lagrangian penalty function technique; (3) investigation of current-injected multiloop controlled switching regulators; and (4) application of optimization for Navy VSTOL energy power system. The generation of the mathematical models and the development and application of computer aided design techniques to solve the different mathematical models are discussed. Recommendations are made for future work that would enhance the application of the computer aided design techniques for power processing systems.

Lee, F. C.↗
NASA NTRS2007

Polar Lunar Regions: Exploiting Natural and Augmented Thermal Environments

In polar regions of the Moon, some areas within craters are permanently shadowed from solar illumination and can reach temperatures of 100 K or less. These regions could serve as cold traps, capturing ice and other volatile compounds. These potential ice stores have many applications for lunar exploration. Within double-shaded craters, even colder regions exist, with temperatures never exceeding 50 K in many cases. Observed temperatures suggest that these regions could enable equivalent liquid nitrogen cryogenic functions. These permanently shaded polar craters also offer unprecedented high-vacuum cryogenic environments, which in their current state could support cryogenic applications. Besides ice stores, the unique conditions at the lunar poles harbor an environment that provides an opportunity to reduce the power, weight, and total mass that needs to be carried from the Earth to the Moon for lunar exploration and research. Reducing the heat flux of geothermal, black body radiation can have significant impacts on the achievable temperature. With a few manmade augmentations, permanently shaded craters located near the lunar poles achieve temperatures even lower than those that naturally exist. Our analysis reveals that lightweight thermal shielding within shaded craters could create an environment several Kelvin above absolute zero. The temperature ranges of both naturally shaded and thermally augmented craters could enable the long-term storage of most gases, low-temperature superconductors for large magnetic fields, devices and advanced high-speed computing instruments. Augmenting thermal conditions in these craters could then be used as a basis for the development of an advanced thermal management architecture that would support a wide variety of cryogenically based applications. Lunar exploration and habitation capabilities would significantly benefit if permanently shaded craters, augmented with thermal shielding, were used to facilitate the operation of near absolute zero instruments, including a wide variety of cryogenically based propulsion, energy, communication, sensing, and computing devices. The required burden of carrying massive life-supporting components from the Earth to the Moon for lunar exploration and research potentially could be reduced.

Ryan, Robert E.↗
NASA NTRSDate not supplied

Delay Tolerant, Radio Frequency Identification (RFID )-enabled Sensing

Radio Frequency Identification (RFID) technology offers a completely passive method to transmit fixed data sequences from an RFID tag, which typically doesn’t have its own power supply, to an interrogator. Radio frequency (RF) energy harvested from the interrogator is rectified by the tag and used to charge an integrated circuit (IC). The IC then modulates the received signal with the data stored on the tag and reflects the energy back to the interrogator. RFID has seen great proliferation in terrestrial inventory management applications, and it has recently made the jump to spaceflight applications onboard the International Space Station, augmenting an existing optical bar‐code infrastructure for tracking supplies. A number of advanced automated logistics management (ALM) concepts employing RFID are currently being developed and evaluated, including so‐called “smart” shelves, cubbies, and trash receptacles using low‐power, embeddable RFID interrogators. An infrastructure where both crew members and robotic assistants, such as autonomous free flyers, are similarly equipped with small RFID interrogators seems likely. It therefore behooves us to consider extending this infrastructure beyond ALM to applications such as low power, embedded sensing. Typically, data on an RFID tag can only be written by an RFID interrogator, using interrogator energy. In recent years, however, a few efforts have focused on using that energy to drive data acquisition from the tag IC, allowing the tag to modify its stored data sequence with sensor data before replying to an interrogator. In this way, the tag can act as a completely passive sensing device. One problem exists with this approach, however: the tag cannot gather data when an interrogator is not present. Thus, strictly passive RFID sensing tags cannot gather data at regular intervals, in the manner of a typical wireless sensor network, without careful, and impractical, planning of mobile interrogator movements. To address this shortcoming, we look to a recent advance in RFID technology which allows an external microprocessor to power the tag IC and write directly into its RFID memory using a wired serial interface. In this paradigm, data gathering is driven by a small, on‐board power supply (using batteries or harvested energy), and data transfer is provided passively through the RFID interrogation service. Since communication typically consumes the lion’s share of power in WSNs, such a technique has the potential to enable extremely long‐lived, embedded wireless sensing when used with extremely low‐current microcontrollers. Since the communication channel is only open when an interrogator is present and actively interrogating the RFID sensing tag, transport of periodically‐sampled sensor data presents itself as a delay/disruption‐tolerant networking (DTN) problem. In this paper, we present the design of a DTN‐like overlay on the common EPC Global, Class 1, Generation 2 RFID standard. This overlay allows seamless, guaranteed data transfer using the EPC Global protocol, supporting extremely low‐power, embedded sensing using an infrastructure likely to be already in place for ALM applications. We evaluate a prototype implementation of a complete end‐to‐end system using a robotic RFID interrogation agent, and we present future directions for the development of this sensing technique.

Raymond S. Wagner↗
NASA NTRS1991

Experimental investigation of a unique airbreathing pulsed laser propulsion concept

Investigations were conducted into unique methods of converting pulsed laser energy into propulsive thrust across a flat impulse surface under atmospheric conditions. The propulsion experiments were performed with a 1-micron neodymium-glass laser at the Space Plasma Branch of the Naval Research Laboratory. Laser-induced impulse was measured dynamically by ballistic pendulums and statically using piezoelectric pressure transducers on a stationary impulse surface. The principal goal was to explore methods for increasing the impulse coupling performance of airbreathing laser-propulsion engines. A magnetohydrodynamic thrust augmentation effect was discovered when a tesla-level magnetic field was applied perpendicular to the impulse surface. The impulse coupling coefficient performance doubled and continued to improve with increasing laser-pulse energies. The resultant performance of 180 to 200 N-s/MJ was found to be comparable to that of the earliest afterburning turbojets.

Myrabo, L. N.↗
NASA NTRS1972

Natural variations in the geomagnetically trapped electron population

Temporal variations in the trapped natural electron flux intensities and energy spectra are discussed and demonstrated using recent satellite data. These data are intended to acquaint the space systems engineer with the types of natural variations that may be encountered during a mission and to augment the models of the electron environment currently being used in space system design and orbit selection. An understanding of the temporal variations which may be encountered should prove helpful. Some of the variations demonstrated here which are not widely known include: (1) addition of very energetic electrons to the outer zone during moderate magnetic storms: (2) addition of energetic electrons to the inner zone during major magnetic storms; (3) inversions in the outer zone electron energy spectrum during the decay phase of a storm injection event and (4) occasional formation of multiple maxima in the flux vs altitude profile of moderately energetic electrons.

Vampola, A. L.↗
NASA NTRS1981

Dish stirling solar receiver combustor test program

The operational and energy transfer characteristics of the Dish Stirling Solar Receiver (DSSR) combustor/heat exchanger system was evaluated. The DSSR is designed to operate with fossil fuel augmentation utilizing a swirl combustor and cross flow heat exchanger consisting of a single row of 4 closely spaced tubes that are curved into a conical shape. The performance of the combustor/heat exchanger system without a Stirling engine was studied over a range of operating conditions and output levels using water as the working fluid. Results show that the combustor may be started under cold conditions, controlled safety, and operated at a constant air/fuel ratio (10 percent excess air) over the required range of firing rates. Furthermore, nondimensional heat transfer coefficients based on total heat transfer are plotted versus Reynolds number and compared with literature data taken for single rows of closely spaced tubes perpendicular to cross flow. The data show enhanced heat transfer for the present geometry and test conditions. Analysis of the results shows that the present system meets specified thermal requirements, thus verifying the feasibility of the DSSR combustor design for final prototype fabrication.

Bankston, C. P.↗
NASA NTRS1989

Experimental studies of adaptive structures for precision performance

An experimental study was made of the adaptive structure concept. Experimental data were obtained for a three-longeron, thirteen-bay truss-type test structure. This test structure can be softly suspended as well as rigidly clamped at the central bay. The load-carrying active member consists of a stack of concentric piezoelectric wafers, an eddy current displacement sensor, and a strain gage force sensor. A bridge (or compound) feedback technique developed in communication engineering is applied to the problem of active damping augmentation in adaptive structures. Using collocated force and velocity feedback around the active member, a desired output mechanical impedance can be implemented to maximize energy absorption by the active members. In addition, large gains can be implemented to linearize the active member's nonlinear behavior. Good agreements with linear finite element analysis was found for both static and dynamic structural responses. An 11 percent damping in the first bending mode was demonstrated in the closed-loop damping experiment.

Chen, G.-S.↗
NASA NTRS2000

Recent Results From The Nasa Earth Science Terra Mission and Future Possibilities

The NASA Earth Sciences Enterprise has made some remarkable strides in recent times in using developing, implementing, and utilizing spaceborne observations to better understand how the Earth works as a coupled, interactive system of the land, ocean, and atmosphere. Notable examples include the Upper Atmosphere Research (UARS) Satellite, the Topology Ocean Experiment (TOPEX) mission, Landsat-7, SeaWiFS, the Tropical Rainfall Monitoring Mission (TRMM), Quickscatt, the Shuttle Radar Topography Mission (SRTM), and, quite recently, the Terra'/Earth Observing System-1 mission. The Terra mission, for example, represents a major step forward in providing sensors that offer considerable advantages and progress over heritage instruments. The Moderate Resolution Imaging Spectrometer (MODIS), the Multi-angle Imaging SpectroRadiometer (MISR), the Measurements of Pollution in the Troposphere (MOPITT), the Advanced Spaceborne Thermal Emissions and Reflections (ASTER) radiometer, and the Clouds and Earth's Radiant Energy System (CERES) radiometer are the instruments involved. Early indications in March indicate that each of these instruments are working well and will be augmenting data bases from heritage instruments as well as producing new, unprecedented observations of land, ocean, and atmosphere features. Several missions will follow the Terra mission as the Earth Observing mission systems complete development and go into operation. These missions include EOS PM-1/'Aqua', Icesat, Vegetation Canopy Lidar (VCL), Jason/TOPEX Follow-on, the Chemistry mission, etc. As the Earth Observing systems completes its first phase in about 2004 a wealth of data enabling better understanding of the Earth and the management of its resources will have been provided. Considerable thought is beginning to be placed on what advances in technology can be implemented that will enable further advances in the early part of the 21st century; e.g., in the time from of 2020. Concepts such as 'constellation' missions or 'formation flying' with 'sensorcraft', 'sensor webs', autonomous operation of satellites, more on-board processing and delivery to individual users, data synthesis and analysis in real-time, etc. are being considered. With the data now having been and soon to be received plus the very real possibilities of further advances in use and applicability of data the potential for very significant gains in knowledge for Earth studies and applications looks quite high in the next decade or two.

Salomonson, Vincent V.↗
NASA NTRS1973

Advantages of the diffuser-augmented wind turbine

Performance optimization for a wind turbine is realized by using a shrouded diffuser to produce up to twice the power of unshrouded turbines of the same diameter. The diffuser converts the kinetic energy of the flow downstream of the rotor into a pressure rise and thus makes it possible for the rotor to capture airflow from a free stream tube area that is greater than that from the rotor itself. The flow velocity through the shrouded rotor is 20 to 60 percent greater than the free wind velocity as opposed to 67 percent less for the unshrouded case. The diffuser also makes it possible to accommodate very high wind speeds without the need of variable pitch in the rotor blades.

Oman, R. A.↗
NASA NTRS1980

Prediction and measurement of turbulent aerodynamic trailing edge flows

A viscous-inviscid interaction algorithm is developed for prediction of two-dimensional mean and fluctuating velocity distributions in the wake immediately downstream of an airfoil trailing edge. A composite pressure field is defined, and a Poisson equation solved for transverse pressure variations. A parabolized form of the time-averaged steady Navier-Stokes equations are solved in conjunction with a viscous-augmented two-dimensional inviscid potential flow analysis. A tensor constitutive equation is employed to predict Reynolds stress distributions from solutions of a turbulence kinetic energy two equation closure model. Numerical predictions compared favorably with detailed experimental data for mean and fluctuating velocities, and Reynolds shear stress distributions, in the trailing edge region of a NACA 63-012 airfoil.

Baker, A. J.↗