Exact intervals and test for mean of symmetrical population when one sample value possibly an outlier
Confidence intervals and significance tests for mean of symmetrical population with smallest or largest outlier observation
Walsh, J.↗
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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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Approximate intervals and tests for products and ratios of binomial probabilities
Approximate confidence interval and tests for products and ratios of binomial probabilities with application in investigating and comparing system reliabilities
Walsh, J. E.↗
The role of space simulation testing in the development of Mariner spacecraft
Thermal/vacuum space simulation assembly level testing for prelaunch confidence of Mariner spacecraft
Devries, T. R.↗
Hypersonic Research Facilities Study - Volume II, Part 2: Phase I Preliminary Studies Flight Vehicle Synthesis
Airbreathing hypersonic aircraft employing liquid hydrogen fuel have the potential of satisfying a number of mission requirements in the 1980-2000 time period. However, major advances in the technological state of the art are necessary before such aircraft can be considered either feasible or practical. The objective was to assess the research and development requirements for hypersonic aircraft and based on these requirements, to provide the NASA with characteristics of a number of desirable hypersonic research facilities. The study is organized in three phases. Phase I is a preliminary analysis of a broad group of concepts. The purpose of Phase I was to compare the characteristics of these facilities considering research capability, versatility, adaptability, system confidence and costs and based on these comparisons select those facilities that appear most attractive for parametric study and further refinement in Phase II. This part of Volume II presents the results of the design and cost synthesis of the flight research facilities.
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Hypersonic Research Facilities Study - Volume IV, Part 1: Phase III Final Studies Flight Research Facilities
The Phase III analyses of Flight Research Facilities performed as a portion of the Hypersonic Research Facilities (HYFAC) Study are presented herein. Two attractive flight research vehicle concepts, geared to the development needs of future (1980-2n00) operational hypersonic aircraft systems, are defined. The inherent research capability of each concept is further expanded by incorporating provisions within the basic vehicle design to accommodate the testing of several additional research options. The design feasibility of this approach to achieving increased research flexibility is examined. Near term propulsion systems are employed as the basic power plants to shorten acquisition time, reduce development costs, and provide high confidence in attaining the performance capability desired, Performance is determined for each basic vehicle and for the vehicles when incorporating several optional research packages. Total program cost estimates are developed for each vehicle and for the various research options. This study provides the necessary framework for the formulation of an attractive and needed flight research program which is a key element in the systematic development of an overall advanced research plan.
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Performance of silicon solar cell assemblies
Solar cell assembly current-voltage characteristics, thermal-optical properties, and power performance were determined. Solar cell cover glass thermal radiation, optical properties, confidence limits, and temperature intensity effects on maximum power were discussed.
Ross, R. G., Jr.↗
Supporting data package for TR 32-1541, effects of storage temperatures on silicon solar cell contacts
A series of summary curves is presented for cells having various contact systems, depicting the effects of temperature exposure as a function of time on the electrical and mechanical characteristics. Each curve represents the results obtained from a minimum of 32 and a maximum of 1104 individual data inputs and includes the 95% confidence limits associated with each time-temperature combination for which measurements were obtained. The curves are useful for detailed analysis and comparison of the behavior of the contact system as a function of the environmental conditions studied.
Berman, P. A.↗
Subsystem radiation susceptibility analysis for deep-space missions
Scientific, unmanned spacecraft on mission to Jupiter and beyond will be subjected to nuclear radiation from the natural environment and onboard nuclear power sources which may be harmful to subsystems. This report postulates these environments and discusses practical considerations to ensure confidence that the spacecraft's materials and subsystems will withstand the effects of anticipated radiation. Degradation mechanisms are discussed.
West, W. S.↗
Relationship between vegetation reflectance spectra and soil geochemistry: New data from Catheart Mountain, Maine
Spectral reflectance curves for red spruce and balsam fir in the 350- to 1100-nanometer region showed differences between specimens growing over and away from a concealed copper deposit at Catheart Mountain, Maine. A sample group of 15 anomalous spruce, 9 background spruce, 10 anomalous fir, and 10 background fir was studied. Measurements of copper and molybdenum contents in the supporting soil were used to categorize the trees as anomalous or background. Analyses using parametric and nonparametric statistical tests were performed to establish whether significant differences existed between the anomalous and background groups. At the 95% confidence level, significant differences were found to exist for both species, generally in the chlorophyll band centered at about 550 nanometers and in the region from 700 to 900 nanometers.
Canney, F. C.↗
Star tracker for the Apollo telescope mount
The star tracker for the Apollo Telescope Mount (ATM) has been designed specifically to meet the requirements of the Skylab vehicle and mission. The functions of the star tracker are presented, as well as descriptions of the optical-mechanical assembly (OMA) and the star tracker electronics (STE). Also included are the electronic and mechanical specifications, interface and operational requirements, support equipment and test requirements, and occultation information. Laboratory functional tests, environmental qualification tests, and life tests have provided a high confidence factor in the performance of the star tracker in the laboratory and on the Skylab mission.
Lee, C. E.↗
Solar activity prediction
A statistical study of formulas for predicting the sunspot number several years in advance is reported. By using a data lineup with cycle maxima coinciding, and by using multiple and nonlinear predictors, a new formula which gives better error estimates than former formulas derived from the work of McNish and Lincoln is obtained. A statistical analysis is conducted to determine which of several mathematical expressions best describes the relationship between 10.7 cm solar flux and Zurich sunspot numbers. Attention is given to the autocorrelation of the observations, and confidence intervals for the derived relationships are presented. The accuracy of predicting a value of 10.7 cm solar flux from a predicted sunspot number is dicussed.
Slutz, R. J.↗
Development and testing of the infrared interferometer spectrometer for the Mariner Mars 1971 spacecraft
The design, development and testing of the infrared interferometer spectrometer is reported with emphasis on the unique features of the Mariner instrument as compared to previous IRIS instruments flown on the Nimbus meteorological research satellites. The interferometer functions in the spectral range from 50 microns to 6.3 microns. A noise equivalent radiance of 0.5 X 10 to the -7th power W/sq cm/ster/cm has been achieved. Major improvements that were implemented included the cesium iodide beamsplitter and electronic features to suppress the effect of vibration on the Michelson mirror motion and digital filtering through the summation of increased sampling of the infrared signal. A bit error detection and correction scheme was also implemented in order to recover the science data with a higher level of confidence over the telecommunication link.
Hanel, R. H.↗
Space shuttle: Aerodynamic heating tests of the MDAC delta wing orbiter and canard booster
Design of an efficient thermal protection system for the space shuttle orbiter and booster is discussed, based on knowledge of the thermal environment to be experienced by the vehicles in all flight phases. The complex configurations of these vehicles limit the level of confidence which can be associated with purely analytical thermal environment predictions. Tests were conducted during April and May 1971 using an orbiter and booster model at a 96-in. hypersonic shock tunnel. Both models were tested separately as well as together. A sufficiently large range in Reynolds number was covered so that laminar, transitional, and turbulent data could be obtained.
Andresen, T. L.↗
Thermal convection at infinite Prandtl number
Numerical solutions are developed for the full scaled three dimensional thermal convection problem, at infinite Prandtl number, and for rigid boundaries. The procedure is designed to give an approximate account of horizontally homogeneous and isotropic flow situations. Results, which included a maximum of 36 horizontal wave number vectors and 20 vertical wave numbers, appear to adequately describe the flow fill up to R = 100,000; beyond this R the results appear to show horizontal wave number truncation error. This error seems to affect the boundary slope of the mean temperature field more than other mean quantities. Despite some numerical uncertainities, certain of the qualitative features of the flow fill are predicted with reasonable confidence.
Herring, J. R.↗
Study program of NASA/GSFC weld quality monitor system
The Weld Quality Monitor has provided online control through the application of linear transducers. The electronic systems must be upgraded to increase confidence level required in production. The Weld Quality Monitor has been used with a recent model solid state power supply to evaluate ability to differentiate between sound and defective weld joints. The Weld Quality Monitor has been evaluated on Dumet and Kovar to interconnect materials Nickel and Alloy 180 in weld joints used on microelectronic module fabrication. Distinct separation was achieved between low strength welds and sound welds by the Quality Monitor. Evaluation performed indicates a drift level at less than 2 percent on a series of 50 consecutive welds. Operation under shop conditions identified need for controlled electrode impact. This was achieved with pneumatic actuation.
Hutchinson, W. R.↗
The risk of solar proton events to space missions
The total dose in rads-tissue from solar protons was tabulated for weekly time intervals, and the number of weeks which gave a dose above 25 rads behind 10 g/sq cm of aluminum for the active 6 years of the 19th cycle were called dangerous or large event weeks. The number of such event weeks was found to be only 3 weeks for the past 20 years. Even though the chance for smaller events is examined, it was found that for any reasonable, high confidence level (95%), the smaller events could be ignored. Consequently, the total particle flux for the 19th cycle was divided by a factor of 3 and determined a single large event week. Using this spectrum, the tissue dose in rads is calculated at the center of an aluminum spherical shell.
Burrell, M. O.↗
Solar cosmic ray hazard to interplanetary and earth-orbital space travel
A statistical treatment of the radiation hazards to astronauts due to solar cosmic ray protons is reported to determine shielding requirements for solar proton events. More recent data are incorporated into the present analysis in order to improve the accuracy of the predicted mission fluence and dose. The effects of the finite data sample are discussed. Mission fluence and dose versus shield thickness data are presented for mission lengths up to 3 years during periods of maximum and minimum solar activity; these correspond to various levels of confidence that the predicted hazard will not be exceeded.
Yucker, W. R.↗
Fatigue failure of materials under broad band random vibrations
The fatigue life of material under multifactor influence of broad band random excitations has been investigated. Parameters which affect the fatigue life are postulated to be peak stress, variance of stress and the natural frequency of the system. Experimental data were processed by the hybrid computer. Based on the experimental results and regression analysis a best predicting model has been found. All values of the experimental fatigue lives are within the 95% confidence intervals of the predicting equation.
Huang, T. C.↗