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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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At least 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
NASA NTRS1948

Free-Spinning, Longitudinal-Trim, and Tumbling Characteristics of a 1/20-Scale Model of the Consolidated Vultke MX-813 (Prototype of XP-92) Airplane as Determined in the Langley 20-Foot Free-Spinning Tunnel

An investigation has been conducted in the Langley 20-foot free-spinning tunnel to evaluate the spin, longitudinal-trim, and tumbling characteristics of a 1/20-scale model of the Consolidated Vultee MX-813 airplane. The effects of control position were determined for the model ballasted to represent the airplane in its design gross weight loading. The model, in general, would not spin but demonstrated a tendency to trim at very high stalled angles of attack. Static tests substantiated the dynamic tests as regards the trim characteristics. Movement of the elevator, however, from up to slightly down was effective in pitching the model from stalled to normal trim attitudes. The model would not tumble.

Stone, Ralph W., Jr.↗
NASA NTRS2005

A Prototype Actuator Concept for Membrane Boundary Vibration Control

In conjunction with the research in ultra-lightweight deployable spacecraft and membrane structures is an underlying need for shape and vibration control. For thin film membrane structures, fundamental modes of vibration for the membrane can be excited through station keeping, attitude adjustments, orbital maneuvers, or contact with space junk or micrometeorites. In order to maintain structural integrity as well as surface shape contour, which may be essential for inflatable antennas, reflective surfaces, or solar sails; vibration damping is a necessary component. This paper discusses development of an actuator attached at the membrane boundary, containing two types of piezoelectric elements, which can be used to perform active control of vibration from the boundary of a membrane. The actuator is designed to control the membrane out-of-plane displacement and in-plane tension by varying the boundary conditions. Results from an initial experimental evaluation of the concept are presented with bench tests of the actuator alone, and with the actuator connected to a large membrane.

Solter, Micah J.↗
NASA NTRS2004

Prototype Training Materials for Acceptance Criteria of Maintenance ASAP Events Occurring Within Social Context

The aviation maintenance community is at a crossroads with respect to implementing the Aviation Safety Action Program (ASAP). While there is considerable interest, several key issues have emerged that cast doubt on how to assure a successful implementation, including buy-in from all levels of the company and training for key participants. There are two objectives for the present report. The first is to provide an examination of limits (or more properly, examples) of the degree of acceptability of more problematic events for risk-based decisions within the current ASAP guidelines. The second objective is to apply these limits of community standards to a set of further refined ASAP training scenarios.

ASAP (AVIATION SAFETY ACTION PROGRAM)↗
NASA NTRS2005

Rapid Prototyping of Biological Materials for In-Space Applications

The topics include: 1) Why is this technology needed? 2) In-Situ Fabrication and Repair (ISFR) and In-Situ Resource Utilization (ISRU); 3) Multi-Material Fabricator; 4) Medical Products; 5) Bioplotter; 6) Closing Remarks; and 7) Additional Information.

Frazier, Natalie↗
NASA NTRS2005

Ion Engine Plume Interaction Calculations for Prototypical Prometheus 1

Prometheus 1 is a conceptual mission to demonstrate the use of atomic energy for distant space missions. The hypothetical spacecraft design considered in this paper calls for multiple ion thrusters, each with considerably higher beam energy and beam current than have previously flown in space. The engineering challenges posed by such powerful thrusters relate not only to the thrusters themselves, but also to designing the spacecraft to avoid potentially deleterious effects of the thruster plumes. Accommodation of these thrusters requires good prediction of the highest angle portions of the main beam, as well as knowledge of clastically scattered and charge exchange ions, predictions for grid erosion and contamination of surfaces by eroded grid material, and effects of the plasma plume on radio transmissions. Nonlinear interactions of multiple thrusters are also of concern. In this paper we describe two- and three-dimensional calculations for plume structure and effects of conceptual Prometheus 1 ion engines. Many of the techniques used have been validated by application to ground test data for the NSTAR and NEXT ion engines. Predictions for plume structure and possible sputtering and contamination effects will be presented.

Mandell, Myron J.↗
NASA NTRS2000

Prototype Lithium-Ion Battery Developed for Mars 2001 Lander

In fiscal year 1997, NASA, the Jet Propulsion Laboratory, and the U.S. Air Force established a joint program to competitively develop high-power, rechargeable lithium-ion battery technology for aerospace applications. The goal was to address Department of Defense and NASA requirements not met by commercial battery developments. Under this program, contracts have been awarded to Yardney Technical Products, Eagle- Picher Technologies, LLC, BlueStar Advanced Technology Corporation, and SAFT America, Inc., to develop cylindrical and prismatic cell and battery systems for a variety of NASA and U.S. Air Force applications. The battery systems being developed range from low-capacity (7 to 20 A-hr) and low-voltage (14 to 28 V) systems for planetary landers and rovers to systems for aircraft that require up to 270 V and for Unmanned Aerial Vehicles that require capacities up to 200 A-hr. Low-Earth-orbit and geosynchronousorbit spacecraft pose additional challenges to system operation with long cycle life (>30,000 cycles) and long calendar life (>10 years), respectively.

Manzo, Michelle A.↗
NASA NTRS2005

Heat Pipe Reactor Dynamic Response Tests: SAFE-100 Reactor Core Prototype

The SAFE-I00a test article at the NASA Marshall Space Flight Center was used to simulate a variety of potential reactor transients; the SAFEl00a is a resistively heated, stainless-steel heat-pipe (HP)-reactor core segment, coupled to a gas-flow heat exchanger (HX). For these transients the core power was controlled by a point kinetics model with reactivity feedback based on core average temperature; the neutron generation time and the temperature feedback coefficient are provided as model inputs. This type of non-nuclear test is expected to provide reasonable approximation of reactor transient behavior because reactivity feedback is very simple in a compact fast reactor (simple, negative, and relatively monotonic temperature feedback, caused mostly by thermal expansion) and calculations show there are no significant reactivity effects associated with fluid in the HP (the worth of the entire inventory of Na in the core is .<el, so fluid movement and temperature changes will cause very minor effects). In previous SAFE-100 tests, the point kinetics model was based on core thermal expansion via deflection measurements. It was found that core deflection was a strung function of how the SAFE-100 modules were fabricated and assembled (in terms of straightness, gaps, and other tolerances). To remove the added variable of how this particular core expands as compared to a different concept, it was decided to use a temperature based feedback model (based on several thermocouples placed throughout the core).

Bragg-Sitton, Shannon M.↗
NASA NTRS2005

Prototype Cryospheric Experimental Synthetic Aperture Radiometer (CESAR)

Present satellite microwave radiometers typically have a coarse spatial resolution of several kilometers or more. This is only adequate only over homogenous areas. Significantly enhanced spatial resolution is critically important to reduce the uncertainty of estimated cryospheric parameters in heterogeneous and climatically-sensitive areas. Examples include: (1) dynamic sea ice areas with frequent lead and polynya developments and variable ice thicknesses, (2) mountainous areas that require improved retrieval of snow water equivalent, and (3) melting outlet glacier or ice shelf areas along the coast of Greenland and Antarctica. For these situations and many others, an Earth surface spot size of no more than 100 m is necessary to retrieve the information needed for significant new scientific progress, including the synthesis of field observations with satellite observations with high confidence.

Hilliard, Lawrence M.↗
NASA NTRS2005

Unsteady Flowfield Around Tandem Cylinders as Prototype for Component Interaction in Airframe Noise

Synergistic application of experiments and numerical simulations is crucial to understanding the underlying physics of airframe noise sources. The current effort is aimed at characterizing the details of the flow interaction between two cylinders in a tandem configuration. This setup is viewed to be representative of several component-level flow interactions that occur when air flows over the main landing gear of large civil transports. Interactions of this type are likely to have a significant impact on the noise radiation associated with the aircraft undercarriage. The paper is focused on two-dimensional, time-accurate flow simulations for the tandem cylinder configuration. Results of the unsteady Reynolds Averaged Navier-Stokes (URANS) computations with a two-equation turbulence model, at a Reynolds number of 0.166 million and a Mach number of 0.166, are presented. The experimental measurements of the same flow field are discussed in a separate paper by Jenkins, Khorrami, Choudhari, and McGinley (2005). Two distinct flow regimes of interest, associated with short and intermediate separation distances between the two cylinders, are considered. Emphasis is placed on understanding both time averaged and unsteady flow features between the two cylinders and in the wake of the rear cylinder. Predicted mean flow quantities and vortex shedding frequencies show reasonable agreement with the measured data for both cylinder spacings. Computations for short separation distance indicate decay of flow unsteadiness with time, which is not unphysical; however, the predicted sensitivity of mean lift coefficient to small angles of attack explains the asymmetric flowfield observed during the experiments.

Khorrami, Meldi R.↗
NASA NTRS2005

Compact, Engineered, 2-Micron Coherent Doppler Wind Lidar Prototype: A New NASA Instrument Incubator Program Project

A new project, selected in 2005 by NASA s Science Mission Directorate (SMD) under the Instrument Incubator Program (IIP), will be described. The 3-year effort is intended to design, fabricate, and demonstrate a packaged, rugged, compact, space-qualifiable coherent Doppler wind lidar (DWL) transceiver capable of future validation in an aircraft and/or Unmanned Aerial Vehicle (UAV). The packaged DWL will utilize the numerous advances in pulsed, solid-state, 2-micron laser technology at NASA s Langley Research Center (LaRC) in such areas as crystal composition, architecture, efficiency, cooling techniques, pulse energy, and beam quality. The extensive experience of Raytheon Space and Airborne Systems (RSAS) in coherent lidar systems, in spacebased sensors, and in packaging rugged lidar systems will be applied to this project. The packaged transceiver will be as close to an envisioned space-based DWL system as the resources and technology readiness allow. We will attempt to facilitate a future upgrade to a coherent lidar system capable of simultaneous wind and CO2 concentration profile measurements. Since aerosol and dust concentration is also available from the lidar signal, the potential for a triple measurement lidar system is attractive for both Earth and Mars remote sensing. A key follow on step after the IIP will be to add a telescope, scanner, and software for aircraft validation. This IIP should also put us in a position to begin a parallel formulation study in the 2006-2007 timeframe for a space-based DWL demonstration mission early next decade.

Kavaya, Michael J.↗
NASA NTRS2006

Precipitation links (PrecipLinks) - a prototype directory for precipitation information

This poster describes a web directory of research oriented precipitation links. In this era of sophisticated search engines and web agents, it might seem counterproductive to establish such a directory of links. However, entering precipitation into a search engine like google will yield over one million hits. To further exacerbate this situation many of the returned links are dead, duplicates of other links, incomplete, or only marginally related to research precipitation or even the broader precipitation area. Sometimes connecting the linked URL causes the browser to lose context and not be able to get back to the original page. Even using more sophisticated search engines query parameters or agents while reducing the overall return doesn't eliminate all of the other issues listed. As part of the development of the measurement-based Precipitation Processing System (PPS) that will support Tropical Rainfall Measuring Mission (TRMM) version 7 reprocessing and the Global Precipitation Measurement (GPM) mission a precipitation links (PrecipLinks) facility is being developed. PrecipLinks is intended to share locations of other sites that contain information or data pertaining to precipitation research. Potential contributors can log-on to the PrecipLinks website and register their site for inclusion in the directory. The price for inclusion is the requirement to place a link back to PrecipLinks on the webpage that is registered. This ensures that users will be able to easily get back to PrecipLinks regardless of any context issues that browsers might have. Perhaps more importantly users while visiting one site that they know can be referred to a location that has many others sites with which they might not be familiar. PrecipLinks is designed to have a very flat structure. This poster summarizes these categories (information, data, services) and the reasons for their selection. Providers may register multiple pages to which they wish to direct users. However, each page may be attached to only one of these categories. Each page to which they refer users will also have a return link to PrecipLinks. The poster describes the operation of the system both the automated and the human processes. It also provides images for the various steps in the registration and use.

Velanthapillia, Balendran↗
NASA NTRS2000

An Operations System for a Planetary Rover Prototype

A distributed operations system, the Web Interface for Telescience (WITS), is being developed for use in future planetary lander and rover mission operations.

Ground operations manipulator control Internet pla↗