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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Hardware development for Gravity Probe-B

Gravity Probe-B (GP-B), also known as the Stanford Relativity Gyroscope Experiment, will test two fundamental predictions of Einstein's General Theory of Relativity by precise measurement of the precessions of nearly perfect gyroscopes in earth orbit. This endeavor embodies state-of-the-art technologies in many fields, including gyroscope fabrication and readout, cryogenics, superconductivity, magnetic shielding, precision optics and alignment methods, and satellite control systems. These technologies are necessary to enable measurement of the predicted precession rates to the milliarcsecond/year level, and to reduce to 'near zero' all non-General Relativistic torques on the gyroscopes. This paper provides a brief overview of the experiment followed by descriptions of several specific hardware items with highlights on progress to date and plans for future development and tests.

Bardas, D.↗
NASA NTRS1989

An ac bridge readout for bolometric detectors

The authors have developed a bolometer readout circuit which greatly improves the low-frequency stability of bolometric detectors. The circuit uses an ac bias voltage and two matched bolometers and allows stable dc bolometer operation for integration times greater than 10 s. In astronomical applications the readout allows for qualitatively different observation modes (e.g. staring or slow-drift scanning) which are particularly well suited for space observations and for the use of arrays. In many applications the readout can increase sensitivity. The authors present noise spectra for 4He temperature bolometers with no excess noise at frequencies greater than 0.1 Hz. The measured optical responsivity of a bolometer operated with the present readout is the same as that of a bolometer operated with a conventional readout.

Rieke, F. M.↗
NASA NTRS1989

A Normal Incidence X-ray Telescope (NIXT) sounding rocket payload

Work on the High Resolution X-ray (HRX) Detector Program is described. In the laboratory and flight programs, multiple copies of a general purpose set of electronics which control the camera, signal processing and data acquisition, were constructed. A typical system consists of a phosphor convertor, image intensifier, a fiber optics coupler, a charge coupled device (CCD) readout, and a set of camera, signal processing and memory electronics. An initial rocket detector prototype camera was tested in flight and performed perfectly. An advanced prototype detector system was incorporated on another rocket flight, in which a high resolution heterojunction vidicon tube was used as the readout device for the H(alpha) telescope. The camera electronics for this tube were built in-house and included in the flight electronics. Performance of this detector system was 100 percent satisfactory. The laboratory X-ray system for operation on the ground is also described.

Golub, Leon↗
NASA NTRS2018

PICO - the Probe of Inflation and Cosmic Origins

The Probe of Inflation and Cosmic Origins (PICO) is a NASA-funded study of a Probe-class mission concept. The top-level science objectives are to probe the physics of the Big Bang by measuring or constraining the energy scale of inflation, probe fundamental physics by measuring the number of light particles in the Universe and the sum of neutrino masses, to measure the reionization history of the Universe, and to understand the mechanisms driving the cosmic star formation history, and the physics of the galactic magnetic field. PICO would have multiple frequency bands between 21 and 799 GHz, and would survey the entire sky, producing maps of the polarization of the cosmic microwave background radiation, of galactic dust, of synchrotron radiation, and of various populations of point sources. Several instrument configurations, optical systems, cooling architectures, and detector and readout technologies have been and continue to be considered in the development of the mission concept. We will present a snapshot of the baseline mission concept currently under development.

Bonato, Matteo↗
NASA NTRS2005

MTRAP: The Magnetic Transition Region Probe

The Magnetic Transition Region Probe is a space telescope designed to measure the magnetic field at several heights and temperatures in the solar atmosphere, providing observations spanning the chromospheric region where the field is expected to become force free. The primary goal is to provide an early warning system (hours to days) for solar energetic particle events that pose a serious hazard to astronauts in deep space and to understand the source regions of these particles. The required magnetic field data consist of simultaneous circular and linear polarization measurements in several spectral lines over the wavelength range from 150 to 855 nm. Because the observations are photon limited an optical telescope with a large (>18sq m) collecting area is required. To keep the heat dissipation problem manageable we have chosen to implement MTRAP with six separate Gregorian telescopes, each with approx. 3 sq m collecting area, that are brought to a common focus. The large field of view (5 x 5 arcmin(sup 2)) and angular resolution (0.025 arcsec pixels) require large detector arrays and, because of the requirements on signal to noise (10(exp 3)), pixels with large full well depths to reduce the readout time and improve the temporal resolution. The optical and engineering considerations that have gone into the development of a concept that meets MTRAP's requirements are described.

Davis, J. M.↗
NASA NTRS1998

Studies of Avalanche Photodiodes (APDS) as Readout Devices for Scintillating Fibers for High Energy Gamma-Ray Astronomy Telescopes

New gamma ray and charged particle telescope designs based on scintillating fiber arrays could provide low cost, high resolution, lightweight, very large area and multi radiation length instrumentation for planned NASA space exploration. The scintillating fibers low visible light output requires readout sensors with single photon detection sensitivity and low noise. The sensitivity of silicon Avalanche Photodiodes (APDS) matches well the spectral output of the scintillating fibers. Moreover, APDs have demonstrated single photon capability. The global aim of our work is to make available to NASA a novel optical detector concept to be used as scintillating fiber readouts and meeting the requirements of the new generations of space-borne gamma ray telescopes. We proposed to evaluate the feasibility of using RMD's small area APDs ((mu)APD) as scintillating fiber readouts and to study possible alternative (mu)APD array configurations for space borne readout scintillating fiber systems, requiring several hundred thousand to one million channels. The evaluation has been conducted in accordance with the task description and technical specifications detailed in the NASA solicitation "Studies of Avalanche Photodiodes (APD as readout devices for scintillating fibers for High Energy Gamma-Ray Astronomy Telescopes" (#8-W-7-ES-13672NAIS) posted on October 23, 1997. The feasibility study we propose builds on recent developments of silicon APD arrays and light concentrators advances at RMD, Inc. and on more than 5 years of expertise in scintillating fiber detectors. In a previous program we carried out the initial research to develop a high resolution, small pixel, solid-state, silicon APD array which exhibited very high sensitivity in the UV-VIS spectrum. This (mu)APD array is operated in Geiger mode and results in high gain (greater than 10(exp 8)), extremely low noise, single photon detection capability, low quiescent power (less than 10 (mu)W/pixel for 30 micrometers sensitive area diameter) and output in the 1-5 volt range. If successful, this feasibility study will make possible the development of a scintillating fiber detector with unsurpassed sensitivity, extremely low power usage, a crucial factor of merit for space based sensors and telescopes.

Vasile, Stefan↗
NASA NTRS1972

Neutron radiographic viewing system

The design, development and application of a neutron radiographic viewing system for use in nondestructive testing applications is considered. The system consists of a SEC vidicon camera, neutron image intensifier system, disc recorder, and TV readout. Neutron bombardment of the subject is recorded by an image converter and passed through an optical system into the SEC vidicon. The vidicon output may be stored, or processed for visual readout.

Source record↗
NASA NTRS1972

Resolution of defects by microwave holography.

Basic techniques for microwave holography are considered, giving attention to ways of approaching the problem, swept frequency depth resolution, optical processing of swept frequency data, B-scans with optical processing, and the side-looking radar principle. Aspects of image formation with Vander Lugt filters are discussed together with holograms for Vander Lugt filter imaging. It is shown that a single basic scanning operation with microwaves can produce records for optical processing to provide any of the common readouts used in flaw detection.

Cribbs, R. W.↗
NASA NTRS2010

LISA Pathfinder Instrument Data Analysis

LISA Pathfinder (LPF) is an ESA-launched demonstration mission of key technologies required for the joint NASA-ESA gravitational wave observatory in space, LISA. As part of the LPF interferometry investigations, analytic models of noise sources and corresponding noise subtraction techniques have been developed to correct for effects like the coupling of test mass jitter into displacement readout, and fluctuations of the laser frequency or optical pathlength difference. Ground testing of pre-flight hardware of the Optical Metrology subsystem is currently ongoing at the Albert Einstein Institute Hannover. In collaboration with NASA Goddard Space Flight Center, the LPF mission data analysis tool LTPDA is being used to analyze the data product of these tests. Furthermore, the noise subtraction techniques and in-flight experiment runs for noise characterization are being defined as part of the mission experiment master plan. We will present the data analysis outcome of preflight hardware ground tests and possible noise subtraction strategies for in-flight instrument operations.

Guzman, Felipe↗
NASA NTRS1978

Investigation of light scattering as a technique for detecting discrete soot particles in a luminous flame

The practicability of using a classical light-scattering technique, involving comparison of angular scattering intensity patterns with theoretically determined Mie and Rayleight patterns, to detect discrete soot particles (diameter less than 50 nm) in premixed propane/air and propane/oxygen-helium flames is considered. The experimental apparatus employed in this investigation included a laser light source, a flat-flame burner, specially coated optics, a cooled photomultiplier detector, and a lock-in voltmeter readout. Although large, agglomerated soot particles were detected and sized, it was not possible to detect small, discrete particles. The limiting factor appears to be background scattering by the system's optics.

Source record↗
NASA NTRS1981

Optical studies of X-ray sources with the MASCOT - A charge-coupled device /CCD/-based astronomical instrument

The performance levels achieved by the MASCOT (MIT Astronomical Spectrometer/Camera for Optical Telescopes) on the 1.3-m telescope at the McGraw-Hill observatory in March 1981 are discussed along with preliminary data obtained in searches for optical counterparts to four 'empty-field' X-ray sources. In the W band (4000-7000 A), the MASCOT achieved a sky-limited sensitivity of +24.4 mag per sq arcsec in an 1800 s integration. The ability to flatten pictures to a level consistent with (sky + source) photon statistics and readout noise was demonstrated. For the four sources observed, an optical counterpart was established for one source (1413+13) based on positional coincidence (better than 1.8 arcsec), four possible candidates were detected in the error box of another source (1009?35) and upper sensitivity limits were established for optical counterparts in the error boxes for the other two sources (0920+39 and 0931-11).

Ricker, G. R.↗
NASA NTRSDate not supplied

Quality Assurance of ISS LIS lightning Data

Optical lighting detection from space has been ongoing since 1995 from the Optical Transient detector (1995-2000), then later by the Lightning Imaging Sensors (LIS) on the Tropical Rainfall Measuring Mission (TRMM) satellite (1997-2015) and the International Space Station (ISS) (ISS 2017-present). A rapid readout (2 ms) 128x128 pixel CCD (Charge-coupled Device) array detects optical transients from lightning (events) and transmits the observations to ground. Ground processing determines whether individual events are likely due to lightning or noise. Likely lightning events are then grouped into groups, flashes, and areas and their location on the earth are determined. The lightning data are saved in orbit files; each file containing the time, location, and intensity of the lightning events, groups, flashes, and areas detected during one orbit. Even after this processing anomalies may exist in some of the orbits. A manual quality assurance (QA) procedure is performed monthly to assess the data and omit orbits with obvious anomalies from the dataset. These files are not included in the final dataset that has undergone QA. The manual QA was developed during the OTD mission to identify artifacts that made it through ground processing algorithms. The manual QA process was continued for the TRMM and ISS LIS missions. Many anomalies have been identified and software updates now address many of them. However, some anomalies still occur in the processed datasets. The manual QA process examines the data for obvious issues in the lightning files that passed through the processing algorithms. These files are considered anomalous and are not included in the final QA dataset. Some issues that may cause an orbit to be considered anomalous include: obvious noise (excess events that make it through the processing), suspect geolocation, and excessive missing data packets. As an example, one way noise manifests is as “streaks” in lightning climatology plots. These streaks are especially apparent in low lightning rate regions (eg., over oceans). Since there is no method at present to extract these anomalies during processing, orbit files with significant anomalies are identified and removed from the final QA ISS LIS dataset. The final QA dataset can be obtained files from the Global Hydrometeorological Resource Center (GHRC). This presentation will provide examples of the various anomalies and examine how often the various anomalies occur and how much data is lost due to the omission of the anomalous orbits. Comparisons with OTD and TRMM LIS will also be examined.

ISS↗
NASA NTRS2007

Array of Bolometers for Submillimeter- Wavelength Operation

A feed-horn-coupled monolithic array of micromesh bolometers is undergoing development for use in a photometric camera. The array is designed for conducting astrophysical observations in a wavelength band centered at 350 m. The bolometers are improved versions of previously developed bolometers comprising metalized Si3N4 micromesh radiation absorbers coupled with neutron- transmutation-doped Ge thermistors. Incident radiation heats the absorbers above a base temperature, changing the electrical resistance of each thermistor. In the present array of improved bolometers (see figure), the thermistors are attached to the micromesh absorbers by indium bump bonds and are addressed by use of lithographed, vapor-deposited electrical leads. This architecture reduces the heat capacity and minimizes the thermal conductivity to 1/20 and 1/300, respectively, of earlier versions of these detectors, with consequent improvement in sensitivity and speed of response. The micromesh bolometers, intended to operate under an optical background set by thermal emission from an ambient-temperature space-borne telescope, are designed such that the random arrival of photons ("photon noise") dominates the noise sources arising from the detector and readout electronics. The micromesh is designed to be a highly thermally and optically efficient absorber with a limiting response time of about 100 s. The absorber and thermistor heat capacity are minimized in order to give rapid speed of response. Due to the minimization of the absorber volume, the dominant source of heat capacity arises from the thermistor.

Bock, James↗
NASA NTRS1974

Improved thermoelectrically cooled quartz crystal microbalance

Design changes in the thermoelectrically-cooled quartz microbalance, which is used to monitor surface contamination in space simulation chambers, is described in terms of its extended temperature range, increased temperature control, mass sensitivity, and cooling power. The mass sensor uses 20 MHz quartz crystals having a sensitivity of 8.8 x 10 to the minus tenth power g/sq cm - Hz. The crystals are optically polished, metal plated, and overplated with magnesium fluoride to simulate an optical surface. The microbalance temperature circuitry is designed to readout and control surface temperature between 100 C and minus 59 C to plus or minus 0.5 C, and readout only temperature between minus 60 C and minus 199 C using auxiliary liquid nitrogen cooling. Data is included on the measurement of oil contamination of surfaces as a function of temperature in space simulation chambers.

D. McKeown↗
NASA NTRS1973

Cryogenic gyroscope housing

A cryogenic gyroscope housing having gas spin-up means provided in annular discs inserted between housing shells is described. A circumferential recess in the inner edges of the discs at their juncture serves as the gas spin-up channel, and recesses in the discs at their junctures with the shells form suction channels. The discs also have inlet and outlet ports communicating with the spin-up channel and exhaust slots communicating with the suction channels. Mating surfaces of the discs and housing shells are held in position by optical contact at the equational plane of the housing. Suspension electrodes and thin-film readout loops are disposed in shells. A centering band and clamp rings provide for proper alinement and placement of parts in formation of optical contact joints.

Angele, W.↗
NASA NTRS1987

The ac and dc electric field meters developed for the US Department of Energy

Two space-potential electric field meters developed at the Jet Propulsion Laboratory under the auspices of the U.S. Department of Energy are described. One of the meters was designed to measure dc fields, the other ac fields. Both meters use fiber optics to couple a small measuring probe to a remote readout device, so as to minimize field perturbation due to the presence of the probe. By using coherent detection, it has been possible to produce instruments whose operating range extends from about 10 V/m up to about 2.5 kV/cm, without the need for range switching on the probe. The electrical and mechanical design of both meters are described in detail. Data from laboratory tests are presented, as well as the results of the tests at the National Bureau of Standards and the Electric Power Research Institute's High Voltage Transmission Research Facility.

Kirkham, H.↗
NASA NTRS1996

Bolometric detector systems for IR and mm-wave space astronomy

Recent developments in bolometric detector systems for millimeter and submillimeter wave space astronomy are described. Current technologies meet all the requirements for the high frequency instrument onboard the cosmic background radiation anisotropy satellite/satellite for the measurement of background anisotropies (COBRAS/SAMBA) platform. It is considered that the technologies that are currently being developed will significantly reduce the effective time constant and/or the cooling requirements of bolometric detectors. These technologies lend themselves to the fabrication of the large format arrays required for the Far Infrared and Submillimeter Space Telescope (FIRST). The scientific goals and detector requirements of the COBRAS/SAMBA platform that will use infrared bolometers are reviewed and the baseline detector system is described, including the feed optics, the infrared filters, the cold amplifiers and the warm readout electronics.

Church, S. E.↗