187,870 research outputs found
Sound separation probe
Probe separates sound waves from turbulent flow pressure fluctuations in ducted airstreams by using principle that sound waves and turbulent flow pressure perturbations travel at different velocities
Image based tracking approaches to AR/C at the Johnson Space Center
Automated Rendezvous and Capture (AR&C) requires the determination of the six degrees of freedom relating two free bodies. Sensor systems that can provide such information have varying sizes, weights, power requirements, complexities and accuracies. One type of sensor system which can provide several key advantages is an image based tracking system, or better known as a machine vision system. By image based tracking we mean that the sensor is some imaging device such as one or more video cameras, from which the tracking parameters necessary to support the rendezvous and capture operations (range, attitude, etc.) can be derived. Image based tracking offers many advantages such as relative hardware simplicity and reprogrammability. These advantages must be weighed against the disadvantages of these systems, such as limited operational range, poorer accuracy at greater distances and sensitivity to lighting conditions. However, with properly designed algorithms and targets these disadvantages can be minimized for many important applications. Rigorous testing in realistic environments can further increase the robustness and reliability of these systems. This presentation describes the facilities used at JSC to support AR&C image based tracking development and the details of our binocular stereo approach to image based tracking
Dynamic characteristics of single crystal SSME blades
The Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) blades are currently manufactured using a directionally solidified (DS) material, MAR-M-246+Hf. However, a necessity to reduce the occurrence of fatigue cracking within the DS blades has lead to an interest in the use of a single crystal (SC) material, PWA-1480. A study was initiated to determine the dynamic characteristics of the HPFTP blades made of SC material and find possible critical engine order excitations. This study examined both the first and second stage drive turbine blades of the HPFTP. The dynamic characterization was done analytically as well as experimentally. The analytical study examined the SC first stage HPFTP blade dynamic characteristics under typical operating conditions. The blades were analyzed using MSC/NASTRAN and a finite element model. Two operating conditions, 27500 RPM and 35000 RPM, were investigated
A binocular stereo approach to AR/C at the Johnson Space Center
Automated Rendezvous and Capture requires the determination of the 6 DOF relating two free bodies. Sensor systems that can provide such information have varying sizes, weights, power requirements, complexities, and accuracies. One type of sensor system that can provide several key advantages is a binocular stereo vision system
Identifying Gaps and Setting Priorities for Employment and Training Research
The report summarizes recent workforce and employment related research, to identify current gaps in employment and training research and makes recommendations for future research processes and priorities that could better inform policy makers, practitioners, job seekers and employers. The report reviews workforce and related research funded by several federal agencies, including the US Departments of Labor, Education, Agriculture, Health and Human Services, and Housing and Urban Development, the National Science Foundation and other federal entities, as well as research undertaken by regional, state and local workforce agencies and philanthrophic organizations
Method of forming thin window drifted silicon charged particle detector Patent
Method of forming thin window drifted silicon charged particle detecto
OGO-3 observations of ELF noise in the magnetosphere - Part 1 - Spatial extent and frequency of occurrence
OGO-3 spectrum analyzer measurements of magnetic noise in magnetospher
Mesospheric wave number spectra from Poker Flat MST radar measurements compared with gravity-wave model
The results of a comparison of mesospheric wind fluctuation spectra computed from radial wind velocity estimates made by the Poker Flat mesosphere-stratosphere-troposphere (MST) radar are compared with a gravity-wave model developed by VanZandt (1982, 1985). The principal conclusion of this comparison is that gravity waves can account for 80% of the mesospheric power spectral density
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