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NASA NTRS2018

Kepler Data Validation I: Architecture, Diagnostic Tests, and Data Products for Vetting Transiting Planet Candidates

The Kepler Mission was designed to identify and characterize transiting planets in the Kepler Field of View and to determine their occurrence rates. Emphasis was placed on identification of Earth-size planets orbiting in the Habitable Zone of their host stars. Science data were acquired for a period of four years. Long-cadence data with 29.4 min sampling were obtained for approx. 200,000 individual stellar targets in at least one observing quarter in the primary Kepler Mission. Light curves for target stars are extracted in the Kepler Science Data Processing Pipeline, and are searched for transiting planet signatures. A Threshold Crossing Event is generated in the transit search for targets where the transit detection threshold is exceeded and transit consistency checks are satisfied. These targets are subjected to further scrutiny in the Data Validation (DV) component of the Pipeline. Transiting planet candidates are characterized in DV, and light curves are searched for additional planets after transit signatures are modeled and removed. A suite of diagnostic tests is performed on all candidates to aid in discrimination between genuine transiting planets and instrumental or astrophysical false positives. Data products are generated per target and planet candidate to document and display transiting planet model fit and diagnostic test results. These products are exported to the Exoplanet Archive at the NASA Exoplanet Science Institute, and are available to the community. We describe the DV architecture and diagnostic tests, and provide a brief overview of the data products. Transiting planet modeling and the search for multiple planets on individual targets are described in a companion paper. The final revision of the Kepler Pipeline code base is available to the general public through GitHub. The Kepler Pipeline has also been modified to support the Transiting Exoplanet Survey Satellite (TESS) Mission which is expected to commence in 2018.

data analysis↗

NASA NTRS2017

Optical Diagnostic Imaging of Multi-Rocket Plume-Induced Base Flow Environments

Non-intrusive optical diagnostic imaging was used for the first time to visualize multi-rocket plume-induced reacting base flows to simulate launch vehicle ascent from sea-level to 250,000 ft. In particular, planar laser induced florescence (PLIF) and infrared (IR) imaging were implemented for the first time to visualize and quantify base flow and rocket plume environments from sub-scale, short-duration propulsion models within a shock tunnel facility. This report discusses the successful imaging diagnostic methods for capturing base flow features and dynamics as a function of altitude. Important base flow and plume features were captured with PLIF and IR diagnostics to develop a conceptual base flow physics model. This imaging data specifically provides insight into the Space Launch System vehicle core-stage and Exploration Upper Stage base environments and further validates short-duration ground test techniques and computational modeling.

Mehta, Manish↗

NASA NTRS2018

Self Diagnostic Accelerometer Field Programmable Gate Array (SDA FPGA)

A self-diagnostic accelerometer (SDA) field programmable gate array (FPGA) may be capable of real time or near-real time diagnostic processing to determine potential accelerometer issues during flight or other mission critical operational situations. The SDA FPGA may determine accelerometer structural health and an attachment condition using an electronics system that is smaller, more energy efficient, and more cost effective than previous diagnostic tools. Advantages of the system may include diagnosing sensors automatically, immediately, actively (i.e., confirming the fault), and consistently, without the influence of a human operator. Customizable SDA algorithms may be adjusted to the specific needs of the sensor/environment.

Tokars, Roger P.↗

NASA NTRS2018

EUV Diagnostics of Optically Thick Plasmas Using the 304 Å Channel

A fundamental limitation of current EUV diagnostic techniques is the need to neglect the He II emission contribution in the 304Å channel. This limits our ability to use strong observations available to us and increases uncertainties in the measurements made. A new EUV diagnostic technique is introduced that accounts for absorption as well as emission contributions from emitting channels such as 304 Å. This new technique can be equally applied to emitting and non-emitting channels, paving the way for more realistic discussion of the heating and energetics of transient plasmas using a wider range of observations. The diagnostic technique is used to compute the dynamics and energetics of a filament eruption observed in the high-cadence SDO/AIA and the associated ICME is observed by ACE/SWICS. The analysis gives us robust measurements of filament dynamics, energetics and its ionization history in the low solar corona. A comparison of these results with results calculated with techniques where He II emission in 304 Å is not considered allowed us to quantify the contribution from emission and comment on the robustness of our method.

EUV↗

NASA NTRS1998

Ultra-Compact Neuroprocessor for Automotive Diagnostic and Control

Demands on the performance of vehicle control and diagnostic systems are steadily increasing as a consequence of stiff global competition and government mandates. In the United States, light trucks and passenger cars are required both to meet strict emission standards and to perform continuous diagnostics of all emissions systems operating in the vehicle.

Neuroprocessor automotive diagnostics↗

NASA NTRS2015

Diagnostic Reasoning using Prognostic Information for Unmanned Aerial Systems

With increasing popularity of unmanned aircraft, continuous monitoring of their systems, software, and health status is becoming more and more important to ensure safe, correct, and efficient operation and fulfillment of missions. The paper presents integration of prognosis models and prognostic information with the R2U2 (REALIZABLE, RESPONSIVE, and UNOBTRUSIVE Unit) monitoring and diagnosis framework. This integration makes available statistically reliable health information predictions of the future at a much earlier time to enable autonomous decision making. The prognostic information can be used in the R2U2 model to improve diagnostic accuracy and enable decisions to be made at the present time to deal with events in the future. This will be an advancement over the current state of the art, where temporal logic observers can only do such valuation at the end of the time interval. Usefulness and effectiveness of this integrated diagnostics and prognostics framework was demonstrated using simulation experiments with the NASA Dragon Eye electric unmanned aircraft.

Diagnostics↗

NASA NTRSDate not supplied

Virtual Diagnostics Interface (ViDI) for Planning Laser-Based Wind Tunnel Experiments

Virtual Diagnostics Interface (ViDI), originally introduced by Richard Schwartz in 2004 and described again by Alderfer, et. al., in 2007, is an interactive 3D software tool developed at NASA Langley Research Center to serve three main purposes: assist in pre-test planning, enhance post-test image analysis and visualization, and serve as a central location for data storage and distribution.1,2 ViDI is composed of custom-developed software and Autodesk® 3ds Max® as it incorporates Computer Aided Design (CAD) models with the results obtained from optical diagnostics.3 This software tool has proven useful in the field of optical diagnostics where pre-test planning of beam paths, optical elements, and test articles must be carried out to avoid interference, ensure spatial resolution is sufficient, and the camera Field of View (FoV) is adequate for the field of interest. Typically, practical considerations such as the distance a camera is from the region of interest, the angles at which the camera is oriented and issues such as the size of the camera and its sensor and size and focal length lens as well as the path of the laser need to be taken into account to predict a successful measurement. An example application of ViDI is shown in Fig.1 where an experiment to investigate flow separation over the wing of the High Lift Common Research Model (HL-CRM) is currently being planned in the National Transonic Facility (NTF) at NASA Langley Research Center.

virtual diagnostics interface↗

NASA NTRSDate not supplied

Advanced Diagnostics for Megahertz Imaging of Mixing, Fuel Spray, and Combustion Processes for Rotating Detonation Combustors

Recent advancements in megahertz rate, high-power, burst-mode laser technology are leveraged to perform and explore imaging measurements that spatially and temporally resolve the mixing, combustion, and detonation flow field in two laboratory-scale rotating detonation combustors (RDCs). In a non-premixed annular RDC, multiple imaging diagnostics are explored to investigate gaseous and liquid injector behavior, the detonation wave structure, and the propellant refill. In one instance, OH planar laser-induced fluorescence (OH-PLIF) imaging is performed up to a 2 MHz repetition rate to track the combustion products and reaction zone locations. In the same annular RDC, a single liquid fuel jet is injected, and laser-based 355-nm imaging of the fuel spray is performed up to a 1 MHz repetition rate. For this configuration, the annular RDC is used as a detonation driver to impose periodic detonation waves to interact with the fuel spray. Moreover, in this annular RDC, a range of tracer-based laser imaging measurements are explored to time-resolve the unsteady oxidizer air recovery and refill process. In a non-premixed linear RDC, planar imaging measurements of the fuel mixing are performed up to a 200 kHz repetition rate using PLIF of a tracer in the fuel supply. The fuel mixing imaging helps explain the origin of the observed pre and post wave burning, detonation structure, and enables quantifying injector recovery timescales. This paper will provide a high-level broad survey of diagnostics applied in these RDCs, lessons learned, and interesting observations.

Combustion↗

NASA NTRSDate not supplied

Advanced Diagnostics For Megahertz Imaging Of Mixing, Fuel Spray, And Combustion Processes For Rotating Detonation Combustors

Combustion↗

NASA NTRSDate not supplied

Assessment of ProgPy - An Open-Source Condition Monitoring and Diagnostics Tool

Traditional maintenance programs, such as corrective and preventive strategies, may lead to high costs and operational inefficiencies. Condition Monitoring and Diagnostics (CM&D) aims to improve these maintenance strategies by enabling timely insights into equipment health and performance. However, implementation of CM&D can be challenging without a robust framework that manages data efficiently, supports interoperability and simplifies integration. To address these challenges ProgPy, an open-source Python-based prognostics tool developed by NASA Ames Research Center, offers a structured solution for broader Prognostics and Health Management (PHM) applications. Ongoing research is assessing the feasibility of implementing ProgPy as a Condition Monitoring and Diagnostics (CM&D) solution by comparing its framework to the guidelines for open CM&D systems recommended in the ISO 13374-2 standard. This evaluation aims to highlight ProgPy’s strengths and identify opportunities for improvement, thereby, contributing to its advancement as an effective tool for Prognostics and Health Management (PHM). This paper presents the results of an initial assessment of the ProgPy toolbox through a gearbox case study using open-source datasets.

Condition-Monitoring, Diagnostics, Failure, Gearbo↗

NASA NTRS1972

Material injection alleviation and plasma diagnostic measurements during the RAM C-III flight.

The results of a material injection RF blackout alleviation experiment and of plasma diagnostic measurements using electrostatic probes and an S-band reflectometer in a 25,000 ft/sec reentry flight are presented. Significant alleviation of RF blackout is observed at altitudes of from 270,000 feet to 120,000 feet due to injection of water and Freon E-3 on VHF, S-band, C-band, and X-band frequencies. Electrostatic probe data, attenuation data, and S-band diagnostic data show consistent plasma results. The relative effectiveness of water and Freon E-3 is discussed.

Schroeder, L. C.↗

NASA NTRS1973

Diagnostic device for monitoring the technical condition of mechanical assemblies

An automatic diagnostic device for monitoring the condition of tractor transmission gears is described. The structural noise spectrum of the gearshift box and rear axle of the tractor were analyzed in a digital computer, by an algorithm based on the multiple correlation method. The optimum assembly of operating frequencies, by use of which the errors in measurement were minimized, was selected from the entire frequency spectrum. Selected frequencies are necessary for choosing the measurement range of the diagnostic device. It turned out that, to obtain a relative error of no more than 2%, it was sufficient to use two filters, vibrating only at the frequencies carrying the maximum data of the mechanical parameter being investigated. The measurement system consists of frequency-selection filters, amplifiers and quadratic detectors, at the outlets of which constant voltages are created, which are proportional to the signal level at the frequencies selected.

Osovskiy, V. I.↗

NASA NTRS1977

Cold plasma diagnostics using satellite measurements of VLF signals from ground transmitters

A diagnostic technique to obtain the cold-plasma density profile in the magnetosphere is introduced. This method uses satellite measurements of group delay and pulse duration of VLF signals from ground transmitters in conjunction with a detailed ray-tracing analysis. An iterative method is involved which starts with an approximate density profile, computes the ray paths for that profile, and then compares the properties of the rays that reach the satellite location with the actual satellite measurements. The density profile is then modified to account for any discrepancies between the two results. The same process is repeated with the new profile until one has reasonable agreement between the data and ray-tracing results. This method is applied to the case of an Imp 6 pass, where strong signals from the Siple VLF transmitter were observed for over 25 min. Good agreement is found between the results of the proposed technique and the well-known ground whistler techniques of cold-plasma diagnostics. The results also serve to illustrate the wide diversity of propagation paths from ground transmitters to high-altitude satellites during VLF wave-injection experiments.

Inan, U. S.↗

NASA NTRS1977

Results of metallographical diagnostic examination of Navy half-watt thermoelectric converters degraded by accelerated tests

To verify the 15-year reliability of the Navy half-watt radioisotope thermoelectric generator (RTG), bismuth-telluride thermoelectric converters were submitted to testing at high temperatures which accelerated the degradation and caused failure of the converters. Metallographic diagnostic examination of failed units verified failure mechanisms. Results of diagnostic examinations are presented.

Rosell, F. E., Jr.↗

NASA NTRS1978

A fluctuation-induced plasma transport diagnostic based upon fast-Fourier transform spectral analysis

A diagnostic, based on fast Fourier-transform spectral analysis techniques, that provides experimental insight into the relationship between the experimentally observable spectral characteristics of the fluctuations and the fluctuation-induced plasma transport is described. The model upon which the diagnostic technique is based and its experimental implementation is discussed. Some characteristic results obtained during the course of an experimental study of fluctuation-induced transport in the electric field dominated NASA Lewis bumpy torus plasma are presented.

Powers, E. J.↗

NASA NTRS1977

A balanced diagnostic system compatible with a barotropic prognostic model

A system of diagnostic equations for the velocity field, or wind laws, for a barotropic primitive-equation model of large-scale atmospheric flow is derived. Attention is given to the classical balance equation and its ellipticity condition. Numerical solutions of the diagnostic system are presented, including examples of cases of the mixed elliptic-hyperbolic type and cases with non-zero divergence. Procedures for implementing such a system are outlined, along with a review of factors in using the technique for operational numerical weather prediction.

Ghil, M.↗

NASA NTRS1978

C III density diagnostics in nonequilibrium plasmas

Mass flow through a temperature gradient can produce substantial departures of the ionization states from their equilibrium values and can change the character of line emission. The effect of such flows on extreme ultraviolet intensities in the solar atmosphere is evaluated for the beryllium-sequence ion C III, which is an easily observed and powerful diagnostic of electron density in a collisionally dominated plasma. A downflow of material in a transition region can lead to an underestimate of the electron density; outflow of material, as in a stellar or solar wind passing from chromospheric to coronal temperatures, yields a reliable density diagnostic. Ambiguities in the analysis of ultraviolet emission lines can be circumvented by measurement of several transitions.

Raymond, J. C.↗

NASA NTRS1983

The LeRC rail accelerators: Test designs and diagnostic techniques

The feasibility of using rail accelerators for various in-space and to-space propulsion applications was investigated. A 1 meter, 24 sq mm bore accelerator was designed with the goal of demonstrating projectile velocities of 15 km/sec using a peak current of 200 kA. A second rail accelerator, 1 meter long with a 156.25 sq mm bore, was designed with clear polycarbonate sidewalls to permit visual observation of the plasma arc. A study of available diagnostic techniques and their application to the rail accelerator is presented. Specific topics of discussion include the use of interferometry and spectroscopy to examine the plasma armature as well as the use of optical sensors to measure rail displacement during acceleration. Standard diagnostics such as current and voltage measurements are also discussed.

Zana, L. M.↗