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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

A new dynamical atmospheric ionizing radiation (AIR) model for epidemiological studies

A new Atmospheric Ionizing Radiation (AIR) model is currently being developed for use in radiation dose evaluation in epidemiological studies targeted to atmospheric flight personnel such as civilian airlines crewmembers. The model will allow computing values for biologically relevant parameters, e.g. dose equivalent and effective dose, for individual flights from 1945. Each flight is described by its actual three dimensional flight profile, i.e. geographic coordinates and altitudes varying with time. Solar modulated primary particles are filtered with a new analytical fully angular dependent geomagnetic cut off rigidity model, as a function of latitude, longitude, arrival direction, altitude and time. The particle transport results have been obtained with a technique based on the three-dimensional Monte Carlo transport code FLUKA, with a special procedure to deal with HZE particles. Particle fluxes are transformed into dose-related quantities and then integrated all along the flight path to obtain the overall flight dose. Preliminary validations of the particle transport technique using data from the AIR Project ER-2 flight campaign of measurements are encouraging. Future efforts will deal with modeling of the effects of the aircraft structure as well as inclusion of solar particle events. Published by Elsevier Ltd on behalf of COSPAR.

Aviation↗
NASA NTRSDate not supplied

Use of an Uninhabited Aircraft System (UAS) for Atmospheric Observations During an Acoustic Flight Test

A jet noise test was performed at Niagara Falls International Airport using a Calspan Learjet 25 by acoustics researchers at NASA Glenn Research Center in partnership with Calspan personnel and Uninhabited Aircraft Systems (UAS) pilots and sensor operators from NASA Langley Research Center. To account for atmospheric attenuation in the de-propagation of jet noise from a ground-based microphone array to the source for comparison with model data collected in a facility at NASA GRC, a vertical profile of atmospheric conditions was required. To that end, a sUAS was flown with a weather sensor package measuring atmospheric pressure, humidity, and temperature in a range of altitudes from ground level to 304.8 m (1,000 ft) above ground level (AGL). The sUAS flights were performed concurrently with and adjacent to the Learjet flight path. Data from these UAS flights are presented herein; additionally, comparisons with conventional balloon-borne instrumentation are made with a particular focus on the quality and capability of UAS-based observations for acoustic flight test applications. Furthermore, a ground-based light detection and ranging (LiDAR) system was deployed for collecting wind magnitude and direction for discrete altitudes up to 304.8 m (1,000 ft) AGL. Data from the LiDAR unit will be presented and discussed in the context of aircraft acoustic flight testing. This effort was supported by NASA’s Commercial Supersonic Technology project.

UAS↗
NASA NTRS1981

Airborne method to minimize fuel with fixed time-of-arrival constraints

A method for generating a minimum-fuel, fixed-range, fixed-time-of-arrival flight path in an on-board flight management system computer for commercial aircraft is described. It is shown that up to 6% of the fuel otherwise used can be saved by means of this capability, despite time-of-arrival delays of up to 30 min, by a medium-range, tri-jet transport aircraft.

Sorensen, J. A.↗
NASA NTRS1993

Multiple-camera/motion stereoscopy for range estimation in helicopter flight

Aiding the pilot to improve safety and reduce pilot workload by detecting obstacles and planning obstacle-free flight paths during low-altitude helicopter flight is desirable. Computer vision techniques provide an attractive method of obstacle detection and range estimation for objects within a large field of view ahead of the helicopter. Previous research has had considerable success by using an image sequence from a single moving camera to solving this problem. The major limitations of single camera approaches are that no range information can be obtained near the instantaneous direction of motion or in the absence of motion. These limitations can be overcome through the use of multiple cameras. This paper presents a hybrid motion/stereo algorithm which allows range refinement through recursive range estimation while avoiding loss of range information in the direction of travel. A feature-based approach is used to track objects between image frames. An extended Kalman filter combines knowledge of the camera motion and measurements of a feature's image location to recursively estimate the feature's range and to predict its location in future images. Performance of the algorithm will be illustrated using an image sequence, motion information, and independent range measurements from a low-altitude helicopter flight experiment.

Smith, Phillip N.↗
NASA NTRS1993

The effect of scene content on speed, time, and distance perception

Helicopter flights performed at low-levels place high demands on pilots; they must simultaneously control the vehicle, avoid obstacles, and navigate. Therefore, pilots must correlate cues viewed in the external scene with information on map in order to maintain their geographical orientation. This is a particularly difficult task when helicopter pilots fly through visually unfamiliar terrain without highly detailed maps. As a result, pilots must often use estimates of elapsed time, distance traveled, and/or average speed in order to maintain a flight path indicated on a map during flight segments when these cues are absent. Therefore, the current study is concerned with the perception of speed, time, and distance, which we assume underlies the ability to orient oneself during these types of flight segments.

Awe, Cynthia A.↗
NASA NTRS2008

Synthetic Vision Displays for Planetary and Lunar Lander Vehicles

Aviation research has demonstrated that Synthetic Vision (SV) technology can substantially enhance situation awareness, reduce pilot workload, improve aviation safety, and promote flight path control precision. SV, and related flight deck technologies are currently being extended for application in planetary exploration vehicles. SV, in particular, holds significant potential for many planetary missions since the SV presentation provides a computer-generated view for the flight crew of the terrain and other significant environmental characteristics independent of the outside visibility conditions, window locations, or vehicle attributes. SV allows unconstrained control of the computer-generated scene lighting, terrain coloring, and virtual camera angles which may provide invaluable visual cues to pilots/astronauts, not available from other vision technologies. In addition, important vehicle state information may be conformally displayed on the view such as forward and down velocities, altitude, and fuel remaining to enhance trajectory control and vehicle system status. The paper accompanies a conference demonstration that introduced a prototype NASA Synthetic Vision system for lunar lander spacecraft. The paper will describe technical challenges and potential solutions to SV applications for the lunar landing mission, including the requirements for high-resolution lunar terrain maps, accurate positioning and orientation, and lunar cockpit display concepts to support projected mission challenges.

Arthur, Jarvis J., III↗
NASA NTRS1976

A technique for generating arbitrarily shaped curved approach paths

A technique for creating and using arbitrarily curved flight paths is described, in conjunction with either automatic or manual guidance. Operating techniques for VTOL aircraft in the terminal area environment are investigated. Straight lines and elliptical segments to connect a series of data points into a continous approach path were developed. Software was created to allow the generation of arbitrarily shaped altitude and speed profiles in conjunction with the lateral curved paths.

Mcconnell, W. J., Jr.↗
NASA NTRS1984

The flight planning - flight management connection

Airborne flight management systems are currently being implemented to minimize direct operating costs when flying over a fixed route between a given city pair. Inherent in the design of these systems is that the horizontal flight path and wind and temperature models be defined and input into the airborne computer before flight. The wind/temperature model and horizontal path are products of the flight planning process. Flight planning consists of generating 3-D reference trajectories through a forecast wind field subject to certain ATC and transport operator constraints. The interrelationships between flight management and flight planning are reviewed, and the steps taken during the flight planning process are summarized.

Sorensen, J. A.↗
NASA NTRS1962

Dyna-Soar Bioastronautics

Dyna-Soar is a manned boost-orbit-glide vehicle. Conventional booster and guidance systems will place the glider on a course at the proper altitude and velocity with the resultant energy to accomplish the planned mission. After boost termination, the pilot verifies the course during orbit and controls the flight path during reentry, approach, and landing. The flight profiles and over-all flight regime for the Dyna-Soar's single-orbit mission will impose no new or extreme environmental hazards on the pilot. '!he environmental parameters of a normal space flight will not expose the pilot to stress magnitudes as great as pilots have experienced in the Mercury flights. Under presently planned flights, the pilot should be in an environment that is well within known human tolerances. We will present the calculated environmental stress to be imposed on the pilot in both normal and emergency conditions and the design techniques .developed to provide a cockpit that will keep the pilot well within his tolerance limits. The various primary environmental parameters will be discussed separately. The solution for each parameter will be discussed in a concurrent manner. No significance is attached to the order in which the specific parameters of the environment are considered.

Spacecraft↗
NASA NTRS1976

Flight of a UV spectrophotometer aboard Galileo 2, the NASA Convair 990 aircraft

An ultraviolet interference-filter spectrophotometer (UVS) fabricated for aircraft-borne use on the DOT Climatic Impact Assessment Program (CIAP) has been successfully tested in a series of flights on the NASA Convair 990, Galileo II. UV flux data and the calculated total ozone above the flight path are reported for several of the flights. Good agreement is obtained with the total ozone as deducted by integration of an ozone sonde vertical profile obtained at Wallops Island, Virginia near the time of a CV-990 underpass. Possible advantages of use of the UVS in the NASA Global Atmospheric Sampling Program are discussed.

Sellers, B.↗
NASA NTRS1987

Path discrepancies between great circle and rhumb line

A simulation of a mathematical model to compute path discrepancies between great circle and rhumb line flight paths is presented. The model illustrates that the path errors depend on the latitude, the bearing, and the trip length of the flight.

Kaul, Rajan↗
NASA NTRS1987

Meteorological context for fall experiments including distributions of water vapor, ozone, and carbon monoxide

Meteorological contexts for the NASA GTE/CITE 1 fall 1983 flight series are presented and discussed. The large-scale wind, cold cloud, and moisture patterns are illustrated by composite diagrams based on the National Oceanic and Atmospheric Administration 700-, 500-, and 250-mbar analyses and the GOES-West broadband and 6.7-micron (water vapor) infrared photographs. Detailed flight path diagrams are included for seven maritime flights and one continental flight in the free troposphere and boundary layer. For three flights from Hickam Field, in Honolulu, HI, to the Intertropical Convergence Zone, vertical profiles of temperature, dew/frost point departures, wind velocity, and ozone, and carbon monoxide mixing ratios are also presented and discussed. Excellent agreement is demonstrated between the in situ and remote measurements. In particular, the predictive and diagnostic value of the 6.7-micron water vapor photographs is demonstrated.

Danielsen, Edwin F.↗
NASA NTRS1988

In-situ measurements of total reactive nitrogen, total water vapor, and aerosols in polar stratospheric clouds in the Antarctic stratosphere

Measurements of total reactive nitrogen, NOy, total water vapor, and aerosols were made as part of the Airborne Antarctic Ozone Experiment. The measurements were made using instruments located onboard the NASA ER-2 aircrafts which conducted twelve flights over the Antarctic continent reaching altitudes of 18 km at 72 S latitude. Each instrument utilized an ambient air sample and provided a measurement up to 1 Hz or every 200 m of flight path. The data presented focus on the flights of Aug. 17th and 18th during which Polar Stratospheric Clouds (PSCs) were encountered containing concentrations of 0.5 to 1.0 micron diameter aerosols greater than 1 cm/cu. The temperature pressure during these events ranged as low as 184 K near 75 mb pressure, with water values near 3.5 ppm by volume (ppmv). With the exception of two short periods, the PSC activity was observed at temperatures above the frost point of water over ice. The data gathered during these flights are analyzed and presented.

Fahey, D. W.↗