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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Single-Event Latchup Testing of the Micrel MIC4424 Dual Power MOSFET Driver

We conducted 47 exposures of four different MIC4424 devices and did not observe any SEL or high-current events. This included worst-case conditions with a LET of 81 MeV-sq cm/mg, applied voltage of 18.5 V, a case temperature greater than 120 C, and a final fluence of 1x10(exp 7)/sq cm. We also monitored both the outputs for the presence of SETs. While the period of the 1 MHz square wave was slightly altered in some cases, no pulses were added or deleted. 1. Purpose: The purpose of this testing is to characterize the BiCMOS/DMOS Micrel MIC4424 dual, non-inverting MOSFET driver for single-event latchup (SEL) susceptibility. These data will be used for flight lot evaluation purposes. 2. Devices Tested: The MIC4423/4424/4425 family are highly reliable BiCMOS/DMOS buffer/driver MOSFET drivers. They are higher output current versions of the MIC4426/4427/4428. They can survive up to 5V of noise spiking, of either polarity, on the ground pin. They can accept, without either damage or logic upset, up to half an amp of reverse current (either polarity) forced back into their outputs. Primarily intended for driving power MOSFETs, the MIC4423/4424/4425 drivers are suitable for driving other loads (capacitive, resistive, or inductive) which require low-impedance, high peak currents, and fast switching times. Heavily loaded clock lines, coaxial cables, or piezoelectric transducers are some examples. The only known limitation on loading is that total power dissipated in the driver must be kept within the maximum power dissipation limits of the package. Five (5) parts were provided for SEL testing. We prepared four parts for irradiation and reserved one piece as an un-irradiated control. More information about the devices can be found in Table 1. The parts were prepared for testing by removing the lid from the CDIP package to expose the target die. The parts were then soldered to small copper circuit adapter boards for easy handling. These parts are fabricated in a bulk BiCMOS/DMOS technology. Since we do not know the number of overlayers used in the fabrication processes, linear energy transfer calculations are determined based on the top-surface incident ion species and kinetic energy.

Power MOSFET↗
NASA NTRS2018

UV Shielding of Bacillus pumilus SAFR-032 Endospores by Martian Regolith Simulants

As exploration of the solar system advances with life detection missions on the horizon, the concern for planetary protection has grown considerably. When attempting to detect extraterrestrial life, the likelihood of false positives from terrestrial contamination must be minimized. The Exposing Microorganisms in the Stratosphere (E-MIST) balloon project aims to evaluate whether resilient terrestrial bacteria can survive stressors in a Mars-like environment. This is accomplished by sending Bacillus pumilus SAFR-032, an endospore-forming bacterial isolate from a spacecraft assembly facility, to the Earth's middle stratosphere (30-38 kilometers), where low temperature and pressure and high radiation and dryness conditions are similar to the surface of Mars. Previous ground and flight tests showed that the vast majority of SAFR-032 spores (99.99 percent) were inactivated by direct sunlight due to ultraviolet (UV) radiation. This observation led us to explore the role of dust shielding in changing microbial survivorship outcomes. To determine the dust particle distributions and density for potentially shielding microbes from UV radiation, samples of a Martian dust simulant were mixed with SAFR-032 spores. The dry heat sterilized simulant used was JSC MARS-1, weathered volcanic ash from Hawaii that displays many chemical and physical properties similar to the Martian soil as characterized by the Viking Lander 1, including reflectance spectrum, chemical composition, mineralogy, grain size, specific gravity, and magnetic properties. First, scanning electron microscopy was undertaken to visualize the aggregation of the spores with dust particles (i.e., shading effects), and samples of varying dust concentrations were subsequently irradiated with UVC light to test survivorship outcomes. After a relationship between dust concentration and spore survivorship was determined, a solar simulator capable of irradiating samples with a fuller UV spectrum (less than 280-400 nanometers) was used to perform a more robust middle stratosphere simulation. Taken together, we will use results from the ground-based irradiation studies to feed into experimental designs for the next E-MIST ultra-long duration polar balloon flight launched by NASA.

Stratosphere↗
NASA NTRS1991

High-Moisture Diet for Laboratory Rats: Complete Blood Counts, Serum Biochemical Values, and Intestinal Enzyme Activity

Rats were fed an irradiated high-moisture diet (KSC-25) with or without access to a water bottle. Physiologic values were compared between these two groups and a group of rats fed a purified diet. Hematologic and serum biochemical values, urine specific gravity, and intestinal enzyme activities were determined from samples collected from the three groups of rats. Sprague Dawley rats (n=32) fed the irradiated high-moisture diet with or without a water bottle were the test animals. Rats (n=16) fed an irradiated purified diet and water provided via a water bottle were the control group. The purified diet formulation, modified AIN-76A, is a commonly used purified diet for laboratory rodents. All rats remained alert and healthy throughout the study. A comparison of the physiologic values of rats in this study with reported normal values indicated that all of the rats in the study were in good health. Significant differences (P less than 0.05) of the physiologic values from each rat group are reported.

Battles, August H.↗
NASA NTRS2021

Design, Calibration, and Application of A Cryogenic Low-Background Infrared Radiometer for Spectral Irradiance and Radiance Measurements From 4- to 20-μm Wavelength

We have constructed, calibrated, and tested a cryogenic low-background infrared (IR) radiometer for both spectral radiance and irradiance measurements over the 4- to 20-μm wavelength range. The primary purpose of the Missile Defense Transfer Radiometer (MDXR) is to measure absolute irradiance or radiance from cryogenic IR test chamber sources using a photoconductive Si:As blocked-impurity band (BIB) detector and a set of spectral filters. The MDXR also includes an absolute cryogenic radiometer (ACR) and a Fourier-transform spectrometer (FTS). For irradiance measurements, the ACR is used to provide the primary power scale for the BIB detector in conjunction with spectral filters, whereas the FTS/BIB configuration derives its scale from an internal blackbody source. The two measurement scales show agreement for the irradiance of highly collimated (<1 mrad) IR beams from 10 -13 to 10 -8 W / μm / cm 2 within the combined relative uncertainties of 2.6% (coverage factor k = 1.) We have also calibrated the radiometer for radiance measurements using a large cavity fluid bath blackbody that overfills the spatial and angular extent of the radiometer entrance pupil. The radiometric calibration uncertainty analysis of the radiometer and its maintenance and stability are discussed.

radiometry↗
NASA NTRS1981

Testing of solar cell covers and encapsulants conducted in a simulated space environment

The materials included in the evaluation were 0211 micro-sheet, FEP-A used as a cover and as an adhesive, DC 93-500 adhesive, PFA "hard coat" used as a cover, GE 615/UV-24 used as a cover, GR 650 used as a cover, and electrostatically bonded 7070 glass. The test environments were 1 MeV electron irradiation interspersed with thermal cycling, 0.5 MeV proton irradiation interspersed with thermal cycling and UV exposure interspersed with thermal cycling. Summary data is given describing the response of the test materials both visually and electrically to the three different environments.

Russell, D. A.↗
NASA NTRS1991

Jellyfish: Special Tools for Biological Research on Earth and in Space

The most intriguing nature of the jellyfish polyps is their ability to metamorphose, giving rise to tiny immature medusae called ephyrae which have a different form or shape from the polyps. The Aurelia Metamorphosis Test System was used to determine the subtle effects of hydrocarbons found in oil spills and the effects of X-irradiation on developing ephyrae. Currently, this test system is used to determine the effects of the gravity-less environment of outer space on the development and behavior of ephyrae. For this purpose, the effects of clinostat rotation on development of the ephyrae and their gravity receptor are being studied. The behavior of the ephyrae during 0 gravity achieved for short intervals of 30 seconds in parabolic flight is examined. The developing ephyrae and the mature ephyrae are exposed to gravity-less environment of outer space via a six or seven day shuttle experiment. If gravity receptors do form in outer space, they will be studied in detail using various types of microscopes, including the electron microscope, to determin whether they developed normally in space as compared with control on Earth.

Spangenberg, Dorothy B.↗
NASA NTRS1984

Dose rate effects in MOS microcircuits

Three read/write random access memories, AM91L24, HM1-6514, and MWS 5114, were subjected to total dose irradiation at three dose rates, with electrical testing after each increment of dosage. Annealing measurements were performed after the radiation tests were completed. The AM91L24 showed a strong dose rate effect and substantial post-irradiation annealing of radiation-induced damage. The dose rate effect was that a lower dose rate produced less net damage than an eqivalent total dose applied at a higher rate. The HM1-6514 showed essentially no dose rate effect and no annealing damage, and the MWS 5114 exhibited a moderate effect with some annealing. It was concluded that dose rate is an important parameter in radiation test procedures for MOS microcircuits and that annealing measurements may be important evaluation aids for such tests.

Cleveland, D. G.↗
NASA NTRS1985

Total integrated dose testing of solid-state scientific CD4011, CD4013, and CD4060 devices by irradiation with CO-60 gamma rays

The total integrated dose response of three CMOS devices manufactured by Solid State Scientific has been measured using CO-60 gamma rays. Key parameter measurements were made and compared for each device type. The data show that the CD4011, CD4013, and CD4060 produced by this manufacturers should not be used in any environments where radiation levels might exceed 1,000 rad(Si).

Dantas, A. R. V.↗
NASA NTRS1971

Variation in spectral irradiance of the SES solar simulator

A test to determine the spectral characteristics of the solar simulation produced by the solar environment simulator (SES) comprised a statistical analysis to determine the spectral variance, and its effect on the average absorptivity of surface coatings.

Mcnutt, A. E.↗
NASA NTRS1986

The effects of space radiation on a chemically modified graphite-epoxy composite material

The effects of the space environment on the engineering properties and chemistry of a chemically modified T300/934 graphite-epoxy composite system are characterized. The material was subjected to 1.0 x 10 to the 10th power rads of 1.0 MeV electron irradiation under vacuum to simulate 30 years in geosynchronous earth orbit. Monotonic tension tests were performed at room temperature (75 F/24 C) and elevated temperature (250 F/121 C) on 4-ply unidirectional laminates. From these tests, inplane engineering and strength properties (E sub 1, E sub 2, Nu sub 12, G sub 12, X sub T, Y sub T) were determined. Cyclic tests were also performed to characterize energy dissipation changes due to irradiation and elevated temperature. Large diameter graphite fibers were tested to determine the effects of radiation on their stiffness and strength. No significant changes were observed. Dynamic-mechanical analysis demonstrated that the glass transition temperature was reduced by 50 F(28 C) after irradiation. Thermomechanical analysis showed the occurrence of volatile products generated upon heating of the irradiated material. The chemical modification of the epoxy did not aid in producing a material which was more radiation resistant than the standard T300/934 graphite-epoxy system. Irradiation was found to cause crosslinking and chain scission in the polymer. The latter produced low molecular weight products which plasticize the material at elevated temperatures and cause apparent material stiffening at low stresses at room temperature.

Reed, S. M.↗
NASA NTRS2000

Simulated Space Environmental Testing on Thin Films

An exploratory program has been conducted, to irradiate some mature commercial and some experimental polymer films with radiation simulating certain Earth orbits, and to obtain data about the response of each test film's reflective and tensile properties. Protocols to conduct optimized tests were considered and developed to a "prototype" level during this program. Fifteen polymer film specimens were arranged on a specially designed test fixture. The fixture featured controlled exposure areas, and protected the ends of the samples for later gripping in tensile tests. The fixture featured controlled exposure areas, and protected the ends of the samples for later gripping in tensile tests. The fixture containing the films was installed in a clean vacuum chamber where protons, electrons and solar ultraviolet (UV) radiation could simultaneously irradiate the specimens. Near realtime UV rates were used, whereas proton and electron rates were accelerated appreciably to simulate 5 years in orbit during a two month test. Periodically, the spectral reflectance of each film was measured in situ. After the end of the irradiation, final reflectance measurements were made in situ, and solar absorptance values were derived for each specimen. These samples were then measured in air for thermal emittance and for tensile strength. Most specimens withstood the irradiation intact, but with reduced reflectance (increased solar absorptance). Thermal emittance changed slightly in several materials, as did their tensile strength and elongation at break. Conclusions are drawn about the performance of the films. Simulated testing to an expected 5 year dose of electrons and protons consistent with those expected at L2 and 0.98 AU orbits and 100 equivalent solar hours exposure.

Russell, Dennis A.↗
NASA NTRS1978

Voyager electronic parts radiation program. Volume 2: Test requirements and procedures

Documents are presented outlining the conditions and requirements of the test program. The Appendixes are as follows: appendix A -- Electron Simulation Radiation Test Specification for Voyager Electronic Parts and Devices, appendix B -- Electronic Piece-Part Testing Program for Voyager, appendix C -- Test Procedure for Radiation Screening of Voyager Piece Parts, appendix D -- Boeing In Situ Test Fixture, and appendix E -- Irradiate - Anneal (IRAN) Screening Documents.

Stanley, A. G.↗
NASA NTRS1980

Effect of High Energy Radiation on Mechanical Properties of Graphite Fiber Reinforced Composites

The flexural strength and average modulus of graphite fiber reinforced composites were tested before and after exposure to 0.5 Mev electron radiation and 1.33 Mev gamma radiation by using a three point bending test (ASTM D-790). The irradiation was conducted on vacuum treated samples. Graphite fiber/epoxy (T300/5208), graphite fiber/polyimide (C6000/PMR 15) and graphite fiber/polysulfone (C6000/P1700) composites after being irradiated with 0.5 Mev electron radiation in vacuum up to 5000 Mrad, show increases in stress and modulus of approximately 12% compared with the controls. Graphite fiber/epoxy (T300/5208 and AS/3501-6), after being irradiated with 1.33 Mev gamma radiation up to 360 Mrads, show increases in stress and modulus of approximately 6% at 167 Mrad compared with the controls. Results suggest that the graphite fiber composites studied should withstand the high energy radiation in a space environment for a considerable time, e.g., over 30 years.

Naranong, N.↗
NASA NTRS1981

The correction for spectral mismatch effects on the calibration of a solar cell when using a solar simulator

A general expression was derived to enable calculation of the calibration error. The information required includes the relative spectral response of the reference cell, the relative spectral response of the cell under test, and the relative spectral irradiance of the simulator (over the spectral range defined by cell response). The spectral irradiance of the solar AMX is assumed to be known.

Seaman, C. H.↗
NASA NTRS1986

Responses of Dielectrics to Space Radiation

Nature, extent, and possible prevention of radiation damage discussed. Report summarizes likely effects of high-energy radiation in outer space on variety of commercially-available dielectric materials used in spacecraft. Effects reported on basis of recent Galileo tests, unpublished tests involving proton or electron irradiation, and published information. In general, organic materials with carbon or inorganic fillers most resistant to radiation.

Bouquet, F. L.↗
NASA NTRS1985

Trends in parts susceptibility to single event upset from heavy ions

New test data have been combined with published data to form a nearly comprehensive body of single event upset (SEU) test data for heavy ion irradiations. These data have been arranged to exibit the SEU susceptibility of devices by function, technology, and manufacturer. Clear trends emerge which should be useful in predicting future device performance.

Nichols, D. K.↗