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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 37 records · Page 2

Photovoltaic module reliability improvement through application testing and failure analysis

During the first four years of the U.S. Department of Energy (DOE) National Photovoltatic Program, the Jet Propulsion Laboratory Low-Cost Solar Array (LSA) Project purchased about 400 kW of photovoltaic modules for test and experiments. In order to identify, report, and analyze test and operational problems with the Block Procurement modules, a problem/failure reporting and analysis system was implemented by the LSA Project with the main purpose of providing manufacturers with feedback from test and field experience needed for the improvement of product performance and reliability. A description of the more significant types of failures is presented, taking into account interconnects, cracked cells, dielectric breakdown, delamination, and corrosion. Current design practices and reliability evaluations are also discussed. The conducted evaluation indicates that current module designs incorporate damage-resistant and fault-tolerant features which address field failure mechanisms observed to date.

Dumas, L. N.↗

Long life monopropellant hydrazine thruster evaluation for Space Station Freedom application - Test results

In support of propulsion system thruster development activity for Space Station Freedom (SSF), NASA Johnson Space Center (JSC) conducted a hydrazine thruster technology demonstration program. The goal of this program was to identify impulse life capability of state-of-the-art long life hydrazine thrusters nominally rated for 50 pounds thrust at 300 psia supply pressure. The SSF propulsion system requirement for impulse life of this thruster class is 1.5 million pounds-seconds, corresponding to a throughput of approximately 6400 pounds of propellant. Long life thrusters were procured from The Marquardt Company, Hamilton Standard, and Rocket Research Company, Testing at JSC was completed on the thruster designs to quantify life while simulating expected thruster firing duty cycles and durations for SSF. This paper presents a review of the SSF propulsion system hydrazine thruster requirements, summaries of the three long life thruster designs procured by JSC and acceptance test results for each thruster, the JSC thruster life evaluation test program, and the results of the JSC test program.

Popp, Christopher G.↗

Development of biaxial test fixture includes cryogenic application

Test fixture has the capability of producing biaxial stress fields in test specimens to the point of failure. It determines biaxial stress by dividing the applied load by the net cross section. With modification it can evaluate materials, design concepts, and production hardware at cryogenic temperatures.

Helf, J. C.↗

Status of the ERDA/NASA photovoltaic tests and applications project

The Tests and Applications Project of the ERDA Photovoltaic Program is concerned with the testing of photovoltaic systems and the growth of their use in real terrestrial applications. This activity is an important complement to the development of low cost solar arrays by providing requirements based on application needs and stimulating markets to create demand to absorb increasing production capacity. A photovoltaic system test facility is now operational, market stimulation has been initiated through applications, and standards for terrestrial cell measurements established.

Deyo, J. N.↗

Review of the Aerodynamic Acceptance Test and Application to Anti-Icing Fluids Testing in the NRC Propulsion and Icing Wind Tunnel

In recent years, the FAA has worked with Transport Canada, National Research Council of Canada (NRC) and APS Aviation, Inc. to develop allowance times for aircraft operations in ice-pellet precipitation. These allowance times are critical to ensure safety and efficient operation of commercial and cargo flights. Wind-tunnel testing with uncontaminated anti-icing fluids and fluids contaminated with simulated ice-pellets had been carried out at the NRC Propulsion and Icing Wind Tunnel (PIWT) to better understand the flowoff characteristics and resulting aerodynamic effects. The percent lift loss on the thin, high-performance wing model tested in the PIWT was determined at 8 angle of attack and used as one of the evaluation criteria in determining the allowance times. Because it was unclear as to how performance degradations measured on this model were relevant to an actual airplane configuration, some means of interpreting the wing model lift loss was deemed necessary. In this report, the lift loss was related to the loss in maximum lift of a Boeing 737-200ADV airplane through the Aerodynamic Acceptance Test (AAT) performed for fluids qualification. This report provides a review of the research basis of the AAT in order to understand how this correlation was applied. A loss in maximum lift coefficient of 5.24 percent on the B737-200ADV airplane (which was adopted as the threshold in the AAT) corresponds to a lift loss of 7.3 percent on the PIWT model at 8 degrees angle of attack. There is significant scatter in the data used to develop the correlation related to varying effects of the various antiicing fluids that were tested and other factors. A statistical analysis indicated the upper limit of lift loss on the PIWT model was 9.2 percent. Therefore, for cases resulting in PIWT model lift loss from 7.3 to 9.2 percent, extra scrutiny of the visual observations is required in evaluating fluid performance with contamination. Additional research may result in future changes to this correlation.

Broeren, Andy P.↗

An evaluation of two flat-black silicone paints for space application

Tests were conducted on two flat-black silicone paints suggested for space applications to determine their optical, electrical, and mechanical properties. Three different types of substrate materials were chosen for these paint tests; the application of the paints onto the primed substrates was carried out by spray coating. The adhesion properties were verified by thermal shock and sudden immersion into liquid nitrogen. A controlled thermal vacuum tests was also carried out by varying the temperature of the paint from -100 to 225 C. The measured optical properties included normal and hemispherical emittance, and solar absorption/reflectance. A simultaneous exposure to low-energy proton/UV irradiation in vacuum, and high-energy proton/electron irradiation was carried out. Additional tests of the paints are described.

Clatterbuck, Carroll H.↗

Bit-error-rate testing of high-power 30-GHz traveling wave tubes for ground-terminal applications

Tests were conducted at NASA Lewis to measure the bit-error-rate performance of two 30 GHz, 200 W, coupled-cavity traveling wave tubes (TWTs). The transmission effects of each TWT were investigated on a band-limited, 220 Mb/sec SMSK signal. The tests relied on the use of a recently developed digital simulation and evaluation system constructed at Lewis as part of the 30/20 GHz technology development program. The approach taken to test the 30 GHz tubes is described and the resultant test data are discussed. A description of the bit-error-rate measurement system and the adaptations needed to facilitate TWT testing are also presented.

Shalkhauser, Kurt A.↗

Development of design, qualification, screening, and application requirements for plastic encapsulated solid-state devices for space applications

Test data were collected on 1035 plastic encapsulated devices and 75 hermetically scaled control group devices that were purchased from each of five different manufacturers in the categories of (1) low power Schottsky TTL (bipolar) digital circuits; (2) CMOS digital circuits; (3) operational amplifier linear circuits; and (4) NPN transistors. These parts were subjected to three different initial screening conditions, then to extended life testing, to determine any possible advantages or trends for any particular screen. Several tests were carried out in the areas of flammability testing, humidity testing, high pressure steam (auroclave) testing, and high temperature storage testing. Test results are presented. Procurement and application considerations for use of plastic encapsulated semiconductors are presented and a statistical analysis program written to study the log normal distributions resulting from life testing is concluded.

Source record↗

Bit-error-rate testing of high-power 30-GHz traveling-wave tubes for ground-terminal applications

Tests were conducted at NASA Lewis to measure the bit-error-rate performance of two 30-GHz 200-W coupled-cavity traveling-wave tubes (TWTs). The transmission effects of each TWT on a band-limited 220-Mbit/s SMSK signal were investigated. The tests relied on the use of a recently developed digital simulation and evaluation system constructed at Lewis as part of the 30/20-GHz technology development program. This paper describes the approach taken to test the 30-GHz tubes and discusses the test data. A description of the bit-error-rate measurement system and the adaptations needed to facilitate TWT testing are also presented.

Shalkhauser, Kurt A.↗

Polymeric Materials Application and Testing for Space Missions

The EM41 Non-metallics polymers team performs polymeric materials screening, characterization, development, qualification, verification and validation testing for flight hardware and in-space applications. They perform insight, testing and application of polymeric materials for launch vehicles and space environments. Personnel have a deep understanding of the technologies associated with cryogenic insulation, high temperature thermal protection materials, paints, primers, coatings, and adhesive materials. Numerous TPS material characterization tests can also be performed by the Lab. The team has both internal and partner test capabilities to subject polymeric materials to Aerospace and Space environments Material properties, response and performance are tested within environments from the launch pad, through the launch environment and into space. A primary role of the team is to select materials and organize test regimen then analyze test results. Test regiment are established to confirm the materials meet the performance requirements levied by customers within the environments that are expected for the mission.

Thermal↗