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Results for “Environmental Testing”

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 1,009 records · Page 56
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

Progress Report for a New Cryogenic Sapphire Oscillator

We present design progress and subsystem test results for a new short-term frequency standard, the Voltage Controlled Sapphire Oscillator (VCSO). Included are sapphire resonator and coupling design, cryocooler environmental sensitivity tests, Q measurement results, and turnover temperature results. A previous report presented history of the design related to resonator frequency and frequency compensation [1]. Performance goals are a frequency stability of 1x10(exp -14) (1 second less than or equal to (tau) less than or equal to 100 seconds) and two years or more continuous operation. Long-term operation and small size are facilitated by use of a small Stirling cryo-cooler (160W wall power) with an expected 5 year life.

oscillator↗
NASA NTRS1997

Fabrication and Qualification of Coated Chip-on-Board Technology for Miniaturized Space Systems

The results of a study carried out in order to manufacture and verify the quality of chip-on-board (COB) packaging technology are presented. The COB, designed for space applications, was tested under environmental stresses, temperature cycling, and temperature-humidity-bias. Both robustness in space applications and in environmental protection on the ground-complete reliability without hermeticity were searched for. The epoxy-parylene combinations proved to be superior to other materials tested.

Maurer, R. H.↗
NASA NTRS1972

End item test plan for the Ultraviolet Spectrometer Experiment S169

The test plan defines the tests to be conducted, identifies and describes all test items, and states the objectives of all tests required to verify that the performance and design goals of the Contract End Item Specification, 7232-0009, have been met and that flight hardware is acceptable. Additionally, environmental conditions, testing time or cycles, allowable maintenance, logging requirements, manner of analysis and utilization of test results, disposition of test specimens, retest requirements, location of tests, facilities and support requirements, and the time phasing of the tests are presented.

Giles, J. R.↗
NASA NTRS1973

Central Atlantic regional ecological test site: A prototype regional environmental information system

During this reporting period progress was made on a Level III land use classification to respond to more detailed user requirements and to exploit the fullest resolution potential of ERTS data. A small area of the Norfolk-Portsmouth SMSA test site was mapped on Level III, with the use of high altitude aerial photography, topographic maps, and other local maps. It was also decided to attempt to identify as many Level III land uses as possible during the land use mapping of CARETS from ERTS.

Robert H Alexander↗
NASA NTRS1997

A Technique for Transient Thermal Testing of Thick Structures

A new open-loop heat flux control technique has been developed to conduct transient thermal testing of thick, thermally-conductive aerospace structures. This technique uses calibration of the radiant heater system power level as a function of heat flux, predicted aerodynamic heat flux, and the properties of an instrumented test article. An iterative process was used to generate open-loop heater power profiles prior to each transient thermal test. Differences between the measured and predicted surface temperatures were used to refine the heater power level command profiles through the iteration process. This iteration process has reduced the effects of environmental and test system design factors, which are normally compensated for by closed-loop temperature control, to acceptable levels. The final revised heater power profiles resulted in measured temperature time histories which deviated less than 25 F from the predicted surface temperatures.

Horn, Thomas J.↗
DOE OSTI2016

Dielectric Characterization of Mylar and The Effects of Doping Processes.

Mylar® polymer is a bi-axially oriented polyethylene terephthalate (PET) polymer film used widely as a dielectric, specifically in capacitors. The dielectric characteristics of Mylar have been well studied and documented over the years; however, many of the mechanisms responsible for dielectric breakdown and failure are not understood for modified versions of the material. Previous studies on Mylar confirm that factors such as temperature, humidity, and voltage ramp rates can also have a significant effect on the dielectric properties and measurement of the dielectric properties. This study seeks to determine how dielectric properties, including permittivity, dielectric loss, and breakdown strength, are affected by doping of the polymer. To do this, two types of Mylar films, virgin film and film doped with a small-molecule electron-acceptor, are tested. Both types of materials are tested under a variety of environmental and experimental conditions, including testing at elevated temperatures, varying relative humidity, and varying ramp rates in dielectric breakdown testing. Analysis of permittivity, dielectric loss, and breakdown strength will be presented comparing virgin and doped Mylar to gain insight into the effects of doping with electron-acceptor molecules on dielectric properties under these varying environmental and test conditions.

36 MATERIALS SCIENCE↗