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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 NTRS2004

Proposing an International Collaboration on Lightweight Autonomous Vehicles to Conduct Scientific Traverses and Surveys over Antarctica and the Surrounding Sea Ice

We have continued to develop a concept for use of autonomous rovers, originally developed for use in planetary exploration, in polar science on Earth; the concept was the subject of a workshop, and this report summarizes and extends that workshop. The workshop on Antarctic Autonomous Scientific Vehicles and Traverses met at the National Geographic Society on February 14 and 15, 2001 to discuss scientific objectives and benefits of the use of autonomous rovers. The participants enthusiastically viewed rovers as being uniquely valuable for such tasks as data taking on tedious or repetitive routes, traverses in polar night, difficult or hazardous routes, extremely remote regions, routes requiring only simple instrumentation, traverses that must be conducted at low speed, augments of manned traverses, and scientific procedures not compatible with human presence or combustion engines. The workshop has concluded that instrumented autonomous vehicles, of the type being developed for planetary exploration, have the potential to contribute significantly to the way science in conducted in Antarctica while also aiding planetary technology development, and engaging the public's interest. Specific objectives can be supported in understanding ice sheet mass balance, sea ice heat and momentum exchange, and surface air chemistry processes. In the interval since the workshop, we have concluded that organized program to employ such rovers to perform scientific tasks in the Fourth International Polar Year would serve the objectives of that program well.

polar science↗
NASA NTRS1999

An Evaluation of Oceanographic Optical Instruments and Deployment Methodologies

The primary objective of the Sea-viewing, Wide Field-of-view Sensor (SeaWiFS) Project is to produce water- leaving radiances with an uncertainty of 5% in clear-water regions and chlorophyll a concentrations within +/- 35% over the range of 0.05-50 mg/cu m. Any global mission, like SeaWiFS, requires validation data be submitted from a wide variety of investigators which places a significant challenge on quantifying the total uncertainty associated with the in situ measurements, because each investigator follows slightly different practices when it comes to implementing all of the steps associated with collecting field data, even those with a prescribed set of protocols. This study uses data from multiple cruises to quantify the uncertainties associated with implementing data collection procedures while utilizing differing in-water optical instruments and deployment methods. A comprehensive approach is undertaken and includes: (1) the use of a portable light source and in-water intercomparisons to monitor the stability of the field radiometers, (2) alternative methods for acquiring reference measurements, and (3) different techniques for making in-water profiles. The only system to meet the 5% radiometric objective of the SeaWiFS Project was a free-fall profiler using (relatively inexpensive) modular components, although a more sophisticated (and comparatively expensive) profiler using integral components was very close and only 1% higher. A relatively inexpensive system deployed with a winch and crane was also close, but the ship shadow contamination problem increased the total uncertainty to approximately 6.5%.

Hooker, Stanford B.↗
NASA NTRS2005

[School-Based UV-B Monitoring Project in Support of EOS-CHEM]

This grant is an extension of Grant NAG5-8929 (Drexel Project Number 230026), resulting from extensions necessary to meet changing science objectives as described in the final report for NAG5-8929, a copy of which is attached. The instrument configuration resulting from NAG54929 has remained basically intact. Cosine response measurements conducted by James Slusser s group at Fort Collins, Colorado, in support of the proposal for Aura ground validation mentioned in the final report for NAG5-8929, indicated that there was significant light leakage to the detector through the sides of the nylon housing. This was easily remedied by machining a removable opaque collar (made from the dark same grey rigid plastic plumbing tubing as the collimating tube) that fits around the detector collar. Also during this grant period, data logging procedures were established for the UV-A instrument, to record irradiance before, during, and after an Aura overflight. This is required in order to compare spatial and temporal variability as required for ground validation of data products derived from the Ozone Monitoring Instrument (OMI). Standalone 12-bit loggers from Onset Computer Corporation (the U12 series), which were not available at the start of these projects, makes possible relatively inexpensive logging for these instruments at a usable resolution. configuration and disposition of these instruments, including the final version of a GLOBE protocol for using the instruments, currently depend on action taken on the Aura ground validation proposal submitted in 2004. A copy of that proposal is attached.

Brooks, David R.↗
NASA NTRS1980

Measurement of Aircraft Speed and Altitude

Problems involved in measuring speed and altitude with pressure-actuated instruments (altimeter, airspeed indicator, true-airspeed indicator, Machmeter, and vertical-speed indicator) are examined. Equations relating total pressure and static pressure to the five flight quantities are presented, and criteria for the design of total and static pressure tubes are given. Calibrations of typical static pressure installations (fuselage nose, wing tip, vertical fin, and fuselage vent) are presented, various methods for flight calibration of these installations are described, and the calibration of a particular installation by two of the methods is described in detail. Equations are given for estimating the effects of pressure lag and leaks. Test procedures for the laboratory calibration of the five instruments are described, and accuracies of mechanical and electrical instruments are presented. Operational use of the altimeter for terrain clearance and vertical separation of aircraft is discussed, along with flight technical errors and overall altitude errors of aircraft in cruise operations. Altitude-measuring techniques based on a variety of properties of the Earth and the atmosphere are included. Two appendixes present airspeed and altitude tables and sample calculations for determining the various flight parameters from measured total and static pressures.

Gracey, W.↗
NASA NTRS1996

Sea WiFS Technical Report Series: The fourth SeaWIFS Intercalibration Round-Robin Experiment (SIRREX-4), May 1995

This report documents the fourth Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Intercalibration Round-Robin Experiment (SIRREX-4), which was held at the National Institute of Standards and Technology (NIST) on 3-10 May 1995. The agenda for SIRREX-4 was established by a consensus reached at the conclusion of SIRREX-3: there should be an emphasis on training and work to foster and encourage uniform use of accepted protocols for calibrating radiometric instruments in the laboratory. The goal was to host the activity in a setting where proper techniques could be discussed and demonstrated. It seemed appealing to split the day between morning lectures and afternoon laboratory exercises or practicals. The former gave the user community a chance to present what was important to them and discuss it with acknowledged experts in radiometry, while the latter presented a unique opportunity for training and evaluation in the presence of these same experts. The five laboratory sessions were concerned with (1) determining the responsivity of a spectroradiometer and the spectral radiance of an unknown integrating sphere source, (2) demonstrating spectral field calibration procedures for an integrating sphere using three different instruments, (3) measuring spectral radiance using the plaque method, (4) setting up and aligning lamp calibration transfer standards using the NIST specifications for irradiance measurements, and (5) characterizing radiometric instruments. In addition to documenting some supplemental studies performed outside the laboratory sessions, this report includes an evaluation of the hardware that has been used during the SIRREX activities plus a critical evaluation of SIRREX objectives.

Johnson, B. Carol↗
NASA NTRS1993

Multi-Angle Imaging SpectroRadiometer (MISR) Design Issues Influenced by Performance Requirements

The design of an Earth remote sensing sensor, such as the Multi-angle Imaging SpectroRadiometer (MISR), begins with a set of science requirements that determine a set of instrument specifications. It is required that the sensor meet these specifications across the image field, over a range of sensor operating temperatures, and throughout mission life. In addition, data quality must be maintained irrespective of bright objects, such as clouds, within the scene, or out-of-field glint sources. During the design phase of MISR, many refinements to the conceptual design have been made to insure that these performance criteria are met. These design considerations are the focus of this paper. Spectral stability with field angle, scene polarization insensitivity, and LTV exposure hardness have, for example, been enabled through a telecentric optical design, a gaussian shaped filter spectral profile used in conjunction with a Lyot depolarizer, and contamination prevention through consideration of material choices and handling procedures. Spectral, radiometric, and MTF stability of the instrument assures the scientific community that MISR imagery can be used for highly accurate aerosol, bi-directional reflectance distribution function (BRDF), and cloud studies.

Bruegge, Carol J.↗
NASA NTRS2014

Adding "Missed" Science to Cassini's Ops Plan

The phenomenal success of the Cassini Mission at Saturn is largely due to flagship instruments, in a target rich environment, for a long period of time, executing almost error free complex mission operations. A smooth transition from cruise operations through the prime science mission and extended science (Equinox) mission culminating in the currently executing Solstice mission has folded in necessary procedural alterations due to improved understanding of the spacecraft, instruments, uplink and planning systems as well as additional science objectives. These have come with the maturation of the mission along with management of workforce reductions. One important set of operational changes has been initiated due to scientific findings highlighting "missed" science opportunities. This is the case for the Titan Meteorology Campaigns and Saturn Storm Watch Campaigns. These observations involve long term monitoring of the atmospheres of Titan and Saturn while the spacecraft and science teams are focused on other high priority targets of opportunity (like Enceladus). Our objective in this paper is to emphasize how a non-invasive strategy to get additional remarkable science was conceived and implemented in a mission with an already well defined operational plan. To illustrate this we will detail Titan Meteorology Campaign and Saturn Storm Watch Campaign integration and implementation strategies as well as the scientific goals and achievements of both.

Roy, Mou↗
NASA NTRS2014

Adding "Missed" Science to Cassini's Ops Plan

The phenomenal success of the Cassini Mission at Saturn is largely due to flagship instruments, in a target rich environment, for a long period of time, executing almost error free complex mission operations. A smooth transition from cruise operations through the prime science mission and extended science (Equinox) mission culminating in the currently executing Solstice mission has folded in necessary procedural alterations due to improved understanding of the spacecraft, instruments, uplink and planning systems as well as additional science objectives. These have come with the maturation of the mission along with management of workforce reductions. One important set of operational changes has been initiated due to scientific findings highlighting "missed" science opportunities. This is the case for the Titan Meteorology Campaigns and Saturn Storm Watch Campaigns. These observations involve long term monitoring of the atmospheres of Titan and Saturn while the spacecraft and science teams are focused on other high priority targets of opportunity (like Enceladus). Our objective in this paper is to emphasize how a non-invasive strategy to get additional remarkable science was conceived and implemented in a mission with an already well defined operational plan. To illustrate this we will detail Titan Meteorology Campaign and Saturn Storm Watch Campaign integration and implementation strategies as well as the scientific goals and achievements of both.

Roy, Mou↗
NASA NTRS2015

Science Training History of the Apollo Astronauts

Following President Kennedy’s initiation of Project Apollo, NASA underwent substantial changes in personnel, organization, and programs and faced a major question: what to do on the Moon after landing. Once a decision that science activities, particularly geoscience, should be pursued, considerable debate ensued over how to accomplish this. Questions arose over instruments and tools required, samples and photos to be returned, landing site selection, and crew composition. Answers to these questions required major efforts for planning traverses on the Moon and training the astronauts in the extensive procedures necessary in low gravity to use tools, set up instruments, take adequate photos, collect and document samples, and provide proper descriptions. In addition to astronauts on the surface, an astronaut in lunar orbit managed additional instruments, photography and verbal descriptions. Training for these activities averaged nearly one hundred hours per month for over a year for each crew. There were many problems as the training progressed: adjusting groups and backgrounds of the training personnel for the best combination of personalities and skills, overcoming logistical troubles, revising awkward procedures, determining optimum means of communications between all involved groups, and devising contingency procedures for real-time problems. By the last mission these problems were overcome.

Phinney, William C.↗
NASA NTRS1973

Fabrication of capsule assemblies, phase 3

Thirteen capsule assemblies were fabricated for evaluation of fuel pin design concepts for a fast spectrum lithium cooled compact space power reactor. These instrumented assemblies were designed for real time test of prototype fuel pins. Uranium mononitride fuel pins were encased in AISI 304L stainless steel capsules. Fabrication procedures were fully qualified by process development and assembly qualification tests. Instrumentation reliability was achieved utilizing specially processed and closely controlled thermocouple hot zone fabrication and by thermal screening tests. Overall capsule reliability was achieved with an all electron beam welded assembly.

Keeton, A. R.↗
NASA NTRS1971

Proposed techniques for launching instrumented balloons into tornadoes

A method is proposed to introduce instrumented balloons into tornadoes by means of the radial pressure gradient, which supplies a buoyancy force driving to the center. Presented are analytical expressions, verified by computer calculations, which show the possibility of introducing instrumented balloons into tornadoes at or below the cloud base. The times required to reach the center are small enough that a large fraction of tornadoes are suitable for the technique. An experimental procedure is outlined in which a research airplane puts an instrumented, self-inflating balloon on the track ahead of the tornado. The uninflated balloon waits until the tornado closes to, typically, 750 meters; then it quickly inflates and spirals up and into the core, taking roughly 3 minutes. Since the drive to the center is automatically produced by the radial pressure gradient, a proper launch radius is the only guidance requirement.

Grant, F. C.↗
NASA NTRS1980

Fatigue strength testing employed for evaluation and acceptance of jet-engine instrumentation probes

This report outlines the fatigue type testing performed on instrumentation rakes and probes intended for use in the air flow passages of jet-engines during full-scale engine tests at Lewis Research Center. Included is a discussion of each type of test performed, the results that may be derived and means of inspection. A design and testing sequence outlines the procedures and considerations involved in the generation of suitable instrument probes.

Armentrout, E. C.↗
NASA NTRS2004

Common Calibration Source for Monitoring Long-term Ozone Trends

Accurate long-term satellite measurements are crucial for monitoring the recovery of the ozone layer. The slow pace of the recovery and limited lifetimes of satellite monitoring instruments demands that datasets from multiple observation systems be combined to provide the long-term accuracy needed. A fundamental component of accurately monitoring long-term trends is the calibration of these various instruments. NASA s Radiometric Calibration and Development Facility at the Goddard Space Flight Center has provided resources to minimize calibration biases between multiple instruments through the use of a common calibration source and standardized procedures traceable to national standards. The Facility s 50 cm barium sulfate integrating sphere has been used as a common calibration source for both US and international satellite instruments, including the Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter Ultraviolet 2 (SBUV/2) instruments, Shuttle SBUV (SSBUV), Ozone Mapping Instrument (OMI), Global Ozone Monitoring Experiment (GOME) (ESA), Scanning Imaging SpectroMeter for Atmospheric ChartographY (SCIAMACHY) (ESA), and others. We will discuss the advantages of using a common calibration source and its effects on long-term ozone data sets. In addition, sphere calibration results from various instruments will be presented to demonstrate the accuracy of the long-term characterization of the source itself.

Kowalewski, Matthew↗
NASA NTRS1972

Spectrofluorometer techniques applicable to sample surfaces

Methods for correcting fluorescence spectra to remove instrumental artifacts are described, including computational and graphical procedures for rapid manual correction by nomographs and similar techniques. Expedient methods for the selection and use of optical filters, the evaluation of filter effectiveness, and the selection of optimum wavelength settings in spectrofluorometry are outlined.

Stoertz, G. E.↗
NASA NTRS1974

The use of the ion probe mass spectrometer in the measurement of hydrogen concentration gradients in Monel K 500

The ion probe mass spectrometer was used to measure hydrogen concentration gradients in cathodically charged Monel K 500. Initial work with the ion probe involved the calibration of the instrument and the establishment of a suitable experimental procedure for this application. Samples of Monel K 500 were cathodically charged in a weak sulfuric acid solution. By varying the current density, different levels of hydrogen were introduced into the samples. Hydrogen concentration gradients were taken by ion sputtering on the surface of these samples and monitoring the behavior of the hydrogen mass peak as a function of time. An attempt was made to determine the relative amounts of hydrogen in the bulk and grain boundaries by analyzing a fresh fracture surface with a higher proportion of grain boundary area. It was found that substantially more hydrogen was detected in the grain boundaries than in the bulk, confirming the predictions of previous workers. A sputter rate determination was made in order to establish the rate of erosion.

Truhan, J. J., Jr.↗
NASA NTRS1977

Aerodynamic coefficient estimation for dynamic wind tunnel models

Maximum likelihood parameter identification is used to estimate the aerodynamic coefficients of a 'flying' aircraft model which is mounted in a transonic wind tunnel by a system of cables and pulleys. The model's motion is governed by both cable and aerodynamic forces, where the parameters to be identified are functions of the aerodynamic forces but cable forces greatly predominate. The test data were successfully processed assuming a linear equation model in the identification procedure. In one instance, the procedure was able to detect a failing measurement instrument. The final parameter estimates are compared to estimates obtained in independent tests of a similar aircraft model.

Mohr, R. L.↗