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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Submillimeter Wave Astronomy Satellite (SWAS) Launch and Early Orbit Support Experiences

The Submillimeter Wave Astronomy Satellite (SWAS) was successfully launched on December 6, 1998 at 00:58 UTC. The two year mission is the fourth in the series of Small Explorer (SMEX) missions. SWAS is dedicated to the study of star formation and interstellar chemistry. SWAS was injected into a 635 km by 650 km orbit with an inclination of nearly 70 deg by an Orbital Sciences Corporation Pegasus XL launch vehicle. The Flight Dynamics attitude and navigation teams supported all phases of the early mission. This support included orbit determination, attitude determination, real-time monitoring, and sensor calibration. This paper reports the main results and lessons learned concerning navigation, support software, star tracker performance, magnetometer and gyroscope calibrations, and anomaly resolution. This includes information on spacecraft tip-off rates, first-day navigation problems, target acquisition anomalies, star tracker anomalies, and significant sensor improvements due to calibration efforts.

Kirschner, S.↗
NASA NTRS1972

End-to-end test of the electron-proton spectrometer

A series of end-to-end tests were performed to demonstrate the proper functioning of the complete Electron-Proton Spectrometer (EPS). The purpose of the tests was to provide experimental verification of the design and to provide a complete functional performance check of the instrument from the excitation of the sensors to and including the data processor and equipment test set. Each of the channels of the EPS was exposed to a calibrated beam of energetic particles, and counts were accumulated for a predetermined period of time for each of several energies. The counts were related to the known flux of particles to give a monodirectional response function for each channel. The measured response function of the test unit was compared to the response function determined for the calibration sensors from the data taken from the calibration program.

Cash, B. L.↗
NASA NTRS1986

Spectroradiometric considerations for advanced land observing systems

Research aimed at improving the inflight absolute radiometric calibration of advanced land observing systems was initiated. Emphasis was on the satellite sensor calibration program at White Sands. Topics addressed include: absolute radiometric calibration of advanced remote sensing; atmospheric effects on reflected radiation; inflight radiometric calibration; field radiometric methods for reflectance and atmospheric measurement; and calibration of field relectance radiometers.

Slater, P. N.↗
NASA NTRS1992

Calibration of satellite sensors in the thermal infrared

The addition of a calibration capability in the 8-14 micron thermal infrared region to the current ground-based calibration of orbiting sensors is discussed. Radiance- and reflectance-based methods are compared. An infrared thermometer was selected as the favored instrument for the determination of ground truth. Three methods to determine the effect of sky background on the thermal emittance of the ground are presented, along with use of LOWTRAN 7 to determine atmospheric effects.

Palmer, James M.↗
NASA NTRS1990

Developing a self-diagnostic system for piezoelectric sensors

Measurement techniques for developing a self-diagnostic system for piezoelectric sensors are presented. The self-diagnostic system uses two types of measurement techniques based on passive and active evaluation of the piezoelectric element. Both hard and soft failures can be detected by this system. Hard failures such as loss of sensor signal and change in sensor output resistance are determined by monitoring the sensor's output resistance, voltage or current. These are passive measurements of the sensor's output condition. Soft failures include changes in sensor calibration and mounting conditions. Soft failures are detected by measuring structural/electrical impedance of the piezoelectric sensor. Active measurement techniques are used to calculate changes in piezoelectric element properties related to soft failures. This paper describes the general operating principles of a self-diagnostic system and discusses the design of an active/passive measurement technique required for this system to function. Experimental results using two types of piezoelectric accelerometers are presented.

Flanagan, Patrick M.↗
NASA NTRS1995

SeaWiFS technical report series. Volume 28: SeaWiFS algorithms, part 1

This document provides five brief reports that address several algorithm investigations sponsored by the Calibration and Validation Team (CVT) within the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project. This volume, therefore, has been designated as the first in a series of algorithm volumes. Chapter 1 describes the initial suite of masks, used to prevent further processing of contaminated radiometric data, and flags, which are employed to mark data whose quality (due to a variety of factors) may be suspect. In addition to providing the mask and flag algorithms, this chapter also describes the initial strategy for their implementation. Chapter 2 evaluates various strategies for the detection of clouds and ice in high latitude (polar and sub-polar regions) using Coastal Zone Color Scanner (CZCS) data. Chapter 3 presents an algorithm designed for detecting and masking coccolithosphore blooms in the open ocean. Chapter 4 outlines a proposed scheme for correcting the out-of-band response when SeaWiFS is in orbit. Chapter 5 gives a detailed description of the algorithm designed to apply sensor calibration data during the processing of level-1b data.

Hooker, Stanford B.↗
NASA NTRS1995

SeaWiFS calibration and algorithm validation

A substantial amount of field research has been completed during this period (1 October 1994 - 31 October 1995). The applicability of different in-flight calibration methods was studied. In addition, various field instruments and new equipment were tested to appraise their usefulness during such calibration activities. The purposes and (expected) results of these field experiments are detailed in separate sections of this report. One section contains a synopsis of calibrations conducted over both land and water targets. A second section contains the results of an experiment conducted to determine the spatial uniformity of surface reflectance at Lake Tahoe, the chosen water calibration site. Advances were also made in the area of radiative transfer software development. An existing exact radiative transfer code, Successive Orders (SO), was modified to provide outputs of the radiance distribution at arbitrary altitudes above a selected calibration target. These modifications were needed to utilize the SO software in radiance-based sensor calibrations. Serious thought was given to the general applicability of various calibration techniques to calibrations conducted over water surfaces. In particular, the practicality of the radiance-based and reflectance-based methods of in-flight radiometric calibration was evaluated.

Parada, Robert J., Jr.↗
NASA NTRS1994

Acoustic calibration apparatus for calibrating plethysmographic acoustic pressure sensors

An apparatus for calibrating an acoustic sensor is described. The apparatus includes a transmission material having an acoustic impedance approximately matching the acoustic impedance of the actual acoustic medium existing when the acoustic sensor is applied in actual in-service conditions. An elastic container holds the transmission material. A first sensor is coupled to the container at a first location on the container and a second sensor coupled to the container at a second location on the container, the second location being different from the first location. A sound producing device is coupled to the container and transmits acoustic signals inside the container.

Zuckerwar, Allan J.↗
NASA NTRS1995

Acoustic calibration apparatus for calibrating plethysmographic acoustic pressure sensors

An apparatus for calibrating an acoustic sensor is described. The apparatus includes a transmission material having an acoustic impedance approximately matching the acoustic impedance of the actual acoustic medium existing when the acoustic sensor is applied in actual in-service conditions. An elastic container holds the transmission material. A first sensor is coupled to the container at a first location on the container and a second sensor coupled to the container at a second location on the container, the second location being different from the first location. A sound producing device is coupled to the container and transmits acoustic signals inside the container.

Zuckerwar, Allan J.↗
NASA NTRS1993

Use of the Airborne Visible/Infrared Imaging Spectrometer to calibrate the optical sensor on board the Japanese Earth Resources Satellite-1

We describe an experiment to calibrate the optical sensor (OPS) on board the Japanese Earth Resources Satellite-1 with data acquired by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). On 27 Aug. 1992 both the OPS and AVIRIS acquired data concurrently over a calibration target on the surface of Rogers Dry Lake, California. The high spectral resolution measurements of AVIRIS have been convolved to the spectral response curves of the OPS. These data in conjunction with the corresponding OPS digitized numbers have been used to generate the radiometric calibration coefficients for the eight OPS bands. This experiment establishes the suitability of AVIRIS for the calibration of spaceborne sensors in the 400 to 2500 nm spectral region.

Green, Robert O.↗
NASA NTRS1975

An aneroid pressure sensor for constant-level balloons

The pressure sensor for the Tropical Wind Energy conversion and Reference Level Experiment (TWERLE) is described. Key design features of the sensor are: capacitive coupling, reference at midrange, up-down counting, passive oven, storage at flight pressure and prelaunch calibration. Sensor specifications are given which are based on the production results of 440 units. Drift, as estimated from simulated life tests, is 1 mb per 6 months. The overall weight of the sensor, including thermal package, is 180 g.

Levanon, N.↗
NASA NTRS1996

The Clouds and the Earth's Radiant Energy System (CERES) Sensors and Preflight Calibration Plans

The Clouds and the Earth's Radiant Energy System (CERES) spacecraft sensors are designed to measure broadband earth-reflected solar shortwave (0.3-5 microns) and earth-emitted longwave (5- > 100 microns) radiances at the top of the atmosphere as part of the Mission to Planet Earth program. The scanning thermistor bolometer sensors respond to radiances in the broadband shortwave (0.3-5 microns) and total-wave (0.3- > 100 microns) spectral regions, as well as to radiances in the narrowband water vapor window (8-12 microns) region. 'ne sensors are designed to operate for a minimum of 5 years aboard the NASA Tropical Rainfall Measuring Mission and Earth Observing System AM-1 spacecraft platforms that are scheduled for launches in 1997 and 1998, respectively. The flight sensors and the in-flight calibration systems will be calibrated in a vacuum ground facility using reference radiance sources, tied to the international temperature scale of 1990. The calibrations will be used to derive sensor gains, offsets, spectral responses, and point spread functions within and outside of the field of view. The shortwave, total-wave, and window ground calibration accuracy requirements (1 sigma) are +/-0.8, +/-0.6, and +/-0.3 W /sq m/sr, respectively, while the corresponding measurement precisions are +/-O.5% and +/-1.0% for the broadband longwave and shortwave radiances, respectively. The CERES sensors, in-flight calibration systems, and ground calibration instrumentation are described along with outlines of the preflight and in-flight calibration approaches.

Lee, Robert B., III↗
NASA NTRS1989

Application of the Langley plot for calibration of sun sensors for the Halogen Occultation Experiment (HALOE)

The calibration of the Halogen Occultation Experiment (HALOE) sun sensor is described. This system consists of two energy-balancing silicon detectors which provide coarse azimuth and elevation control signals and a silicon photodiode array which provides top and bottom solar edge data for fine elevation control. All three detectors were calibrated on a mountaintop near Tucson, Ariz., using the Langley plot technique. The conventional Langley plot technique was modified to allow calibration of the two coarse detectors, which operate wideband. A brief description of the test setup is given. The HALOE instrument is a gas correlation radiometer that is now being developed for the Upper Atmospheric Research Satellite.

Moore, Alvah S., Jr.↗
NASA NTRS1990

Remote sensing science for the Nineties; Proceedings of IGARSS '90 - 10th Annual International Geoscience and Remote Sensing Symposium, University of Maryland, College Park, May 20-24, 1990. Vols. 1, 2, & 3

Various papers on remote sensing (RS) for the nineties are presented. The general topics addressed include: subsurface methods, radar scattering, oceanography, microwave models, atmospheric correction, passive microwave systems, RS in tropical forests, moderate resolution land analysis, SAR geometry and SNR improvement, image analysis, inversion and signal processing for geoscience, surface scattering, rain measurements, sensor calibration, wind measurements, terrestrial ecology, agriculture, geometric registration, subsurface sediment geology, radar modulation mechanisms, radar ocean scattering, SAR calibration, airborne radar systems, water vapor retrieval, forest ecosystem dynamics, land analysis, multisensor data fusion. Also considered are: geologic RS, RS sensor optical measurements, RS of snow, temperature retrieval, vegetation structure, global change, artificial intelligence, SAR processing techniques, geologic RS field experiment, stochastic modeling, topography and Digital Elevation model, SAR ocean waves, spaceborne lidar and optical, sea ice field measurements, millimeter waves, advanced spectroscopy, spatial analysis and data compression, SAR polarimetry techniques. Also discussed are: plant canopy modeling, optical RS techniques, optical and IR oceanography, soil moisture, sea ice back scattering, lightning cloud measurements, spatial textural analysis, SAR systems and techniques, active microwave sensing, lidar and optical, radar scatterometry, RS of estuaries, vegetation modeling, RS systems, EOS/SAR Alaska, applications for developing countries, SAR speckle and texture.

Source record↗
DOE OSTI2026

Portable and Cost-Effective Device for Reliable Detection of Counterfeit and Non-compliant Refrigerants in Diverse Applications

Counterfeit refrigerants pose significant challenges to safety, system reliability, and operational effectiveness due to their harmful contaminants or incompatible chemical compositions. Utilizing these noncompliant products can lead to reduced efficiency, equipment failures, and expensive repairs. Additionally, heightened demand for alternative refrigerants during the industry's transition has created supply gaps, enabling counterfeit products to proliferate. Accurate detection and analysis tools are therefore essential to verify refrigerant authenticity and ensure system integrity in diverse applications. This paper presents the development of a portable device designed for reliable identification and detailed analysis of refrigerant composition. By integrating precision gas sampling, controlled pressure regulation, and automated sensor technology, the device not only detects deviations from standard refrigerant properties but also provides a comprehensive composition breakdown. Pre-calibrated sensors measure the refrigerant gas to identify specific concentrations and contaminants, with an intuitive LED-based indicator system ensuring quick interpretation of results. The user-friendly interface enables operators to select refrigerant types for targeted testing, further enhancing accuracy and usability for field technicians. Comprehensive testing was conducted on mildly flammable A2L refrigerants, showcasing the device’s robustness and adaptability in analyzing composition and detecting discrepancies. The device demonstrated consistent accuracy across a range of refrigerant samples, affirming its reliability in diverse operational environments. Its design minimizes contamination risks during sampling and provides detailed composition results within 90 seconds, ensuring efficient and precise analysis. With a projected price point under $150, the proposed solution delivers affordability alongside its lightweight portability and straightforward operation. Unlike complex and costly alternatives, such as gas chromatography systems, this device provides an accessible option for technicians, customs personnel, and industry operators in need of quick and effective refrigerant verification. Compatible with both current formulations and emerging refrigerant technologies, the device addresses critical counterfeit detection needs across a range of applications. By delivering accurate composition analysis and counterfeit identification, this innovation enhances system performance, safety, and operational reliability in crucial industries.

Cheekatamarla, Praveen [ORNL] (ORCID:0000000248827↗
NASA NTRS1980

Applications of HCMM satellite data

Underflight data were radiometrically calibrated at several locations and surface water temperature measurements were made for several areas approximating the field of view of the HCMM sensor in a study of the thermal properties of Lake Ontario and Lake Erie and of the heat island problem in selected areas adjacent to these lakes. The temperatures obtained from the radiometrically collected imagery were then plotted against the apparent temperatures for these same locations obtained from HCMM computer compatible tapes. The sensor calibration provides a foundation for development of a refined model for radiometric correction of HCMM data to produce maps of thermal bar development in Lake Ontario. Thermal patterns of several urban areas were generated from HCMM tapes and scaled to corresponding land use and topographic maps. The resulting map overlays are being interpreted in terms of land use influence on the extend and severity of heat island indicators.

Source record↗
NASA NTRS1993

Improved Calibration Of Acoustic Plethysmographic Sensors

Improved method of calibration of acoustic plethysmographic sensors involves acoustic-impedance test conditions like those encountered in use. Clamped aluminum tube holds source of sound (hydrophone) inside balloon. Test and reference sensors attached to outside of balloon. Sensors used to measure blood flow, blood pressure, heart rate, breathing sounds, and other vital signs from surfaces of human bodies. Attached to torsos or limbs by straps or adhesives.

Zuckerwar, Allan J.↗