Discussion of telemetry performance standards Technical memorandum no. 40
Telemetry operation performance standards in terms of error and rejection probabilities
TELEMETRY↗
SEARCH · Search NASA
Results for “OPERATOR PERFORMANCE”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Integration of MSFC Usability Lab with Usability Testing
As part of the Stage Analysis Branch, human factors engineering plays an important role in relating humans to the systems of hardware and structure designs of the new launch vehicle. While many branches are involved in the technical aspects of creating a launch vehicle, human factors connects humans to the scientific systems with the goal of improving operational performance and safety while reducing operational error and damage to the hardware. Human factors engineers use physical and computerized models to visualize possible areas for improvements to ensure human accessibility to components requiring maintenance and that the necessary maintenance activities can be accomplished with minimal risks to human and hardware. Many methods of testing are used to fulfill this goal, such as physical mockups, computerized visualization, and usability testing. In this analysis, a usability test is conducted to test how usable a website is to users who are and are not familiar with it. The testing is performed using participants and Morae software to record and analyze the results. This analysis will be a preliminary test of the usability lab in preparation for use in new spacecraft programs, NASA Enterprise, or other NASA websites. The usability lab project is divided into two parts: integration of the usability lab and a preliminary test of the usability lab.
Cheng, Yiwei↗
Edge and line detection in ERTS imagery: A comparative study
Several local edge detection operators were applied to a set of ERTS pictures of the Monterey, Calif. area. Gradient operators performed consistently better than laplacian operators in detecting edges. It was also found that if a grayscale normalization operation, histogram flattening, was applied to the pictures first, the edge detector outputs were greatly enhanced. The use of interpolation for more accurate location of edges on a digital picture was also briefly investigated. Curve detection operators were applied to the edge detector outputs; this had the effect of enhancing the edges while suppressing noise.
Eberlein, R.↗
The Effects of the Mars Exploration Rovers (MER) Work Schedule Regime on Locomotor Activity Circadian Rhythms, Sleep and Fatigue
This study assessed human adaptation to a Mars sol by evaluating sleep metrics obtained by actigraphy and subjective responses in 22 participants, and circadian rhythmicity in locomotor activity in 9 participants assigned to Mars Exploration Rover (MER) operational work schedules (24.65 hour days) at the Jet Propulsion Laboratory in 2004. During MER operations, increased work shift durations and reduced sleep durations and time in bed were associated with the appearance of pronounced 12-hr (circasemidian) rhythms with reduced activity levels. Sleep duration, workload, and circadian rhythm stability have important implications for adaptability and maintenance of operational performance not only of MER operations personnel but also in space crews exposed to a Mars sol of 24.65 hours during future Mars missions.
DeRoshia, Charles W.↗
Analysis of Separation Corridors for Visiting Vehicles from the International Space Station
The International Space Station (ISS) is a very dynamic vehicle with many operational constraints that affect its performance, operations, and vehicle lifetime. Most constraints are designed to alleviate various safety concerns that are a result of dynamic activities between the ISS and various Visiting Vehicles (VVs). One such constraint that has been in place for Russian Vehicle (RV) operations is the limitation placed on Solar Array (SA) positioning in order to prevent collisions during separation and subsequent relative motion of VVs. An unintended consequence of the SA constraint has been the impacts to the operational flexibility of the ISS resulting from the reduced power generation capability as well as from a reduction in the operational lifetime of various SA components. The purpose of this paper is to discuss the technique and the analysis that were applied in order to relax the SA constraints for RV undockings, thereby improving both the ISS operational flexibility and extending its lifetime for many years to come. This analysis focused on the effects of the dynamic motion that occur both prior to and following RV separations. The analysis involved a parametric approach in the conservative application of various initial conditions and assumptions. These included the use of the worst case minimum and maximum vehicle configurations, worst case initial attitudes and attitude rates, and the worst case docking port separation dynamics. Separations were calculated for multiple ISS docking ports, at varied deviations from the nominal undocking attitudes and included the use of two separate attitude control schemes: continuous free-drift and a post separation attitude hold. The analysis required numerical propagation of both the separation motion and the vehicle attitudes using 3-degree-of-freedom (DOF) relative motion equations coupled with rigid body rotational dynamics to generate a large set of separation trajectories.
Zaczek, Mariusz P.↗
Advanced optical blade tip clearance measurement system
An advanced electro-optical system was developed to measure single blade tip clearances and average blade tip clearances between a rotor and its gas path seal in an operating gas turbine engine. This system is applicable to fan, compressor, and turbine blade tip clearance measurement requirements, and the system probe is particularly suitable for operation in the extreme turbine environment. A study of optical properties of blade tips was conducted to establish measurement system application limitations. A series of laboratory tests was conducted to determine the measurement system's operational performance characteristics and to demonstrate system capability under simulated operating gas turbine environmental conditions. Operational and environmental performance test data are presented.
Ford, M. J.↗
Liquid Oxygen/Liquid Methane Integrated Propulsion System Test Bed
In support of NASA?s Propulsion and Cryogenic Advanced Development (PCAD) project, a liquid oxygen (LO2)/liquid methane (LCH4) Integrated Propulsion System Test Bed (IPSTB) was designed and advanced to the Critical Design Review (CDR) stage at the Johnson Space Center. The IPSTB?s primary objectives are to study LO2/LCH4 propulsion system steady state and transient performance, operational characteristics and to validate fluid and thermal models of a LO2/LCH4 propulsion system for use in future flight design work. Two phase thermal and dynamic fluid flow models of the IPSTB were built to predict the system performance characteristics under a variety of operating modes and to aid in the overall system design work. While at ambient temperature and simulated altitude conditions at the White Sands Test Facility, the IPSTB and its approximately 600 channels of system instrumentation would be operated to perform a variety of integrated main engine and reaction control engine hot fire tests. The pressure, temperature, and flow rate data collected during this testing would then be used to validate the analytical models of the IPSTB?s thermal and dynamic fluid flow performance. An overview of the IPSTB design and analytical model development will be presented.
Flynn, Howard↗
Conceptual design study of potential early commercial MHD powerplant. Report of task 2 results
The conceptual design of one of the potential early commercial MHD power plants was studied. The plant employs oxygen enrichment of the combustion air and preheating of this oxygen enriched air to an intermediate temperature of 1200 F attainable with a tubular type recuperative heat exchanger. Conceptual designs of plant componets and equipment with performance, operational characteristics, and costs are reported. Plant economics and overall performance including full and part load operation are reviewed. The projected performance and estimated cost of this early MHD plant are compared to conventional power plants, although it does not offer the same high efficiency and low costs as the mature MHD power plant. Environmental aspects and the methods incorporated in plant design for emission control of sulfur and nitrogen are reviewed.
Hals, F. A.↗
STS-52 Space Shuttle mission report
The STS-52 Space Shuttle Program Mission Report provides a summary of the Orbiter, External Tank (ET), Solid Rocket Booster/Redesigned Solid Rocket Motor (SRB/RSRM), and the Space Shuttle main engine (SSME) subsystem performance during the fifty-first flight of the Space Shuttle Program, and the thirteenth flight of the Orbiter vehicle Columbia (OV-102). In addition to the Orbiter, the flight vehicle consisted of the following: an ET (designated as ET-55/LWT-48); three SSME's, which were serial numbers 2030, 2015, and 2034 in positions 1, 2, and 3, respectively; and two SRB's, which were designated BI-054. The lightweight RSRM's that were installed in each SRB were designated 360L027A for the left SRB and 360Q027B for the right SRB. The primary objectives of this flight were to successfully deploy the Laser Geodynamic Satellite (LAGEOS-2) and to perform operations of the United States Microgravity Payload-1 (USMP-1). The secondary objectives of this flight were to perform the operations of the Attitude Sensor Package (ASP), the Canadian Experiments-2 (CANEX-2), the Crystals by Vapor Transport Experiment (CVTE), the Heat Pipe Performance Experiment (HPP), the Commercial Materials Dispersion Apparatus Instrumentation Technology Associates Experiments (CMIX), the Physiological System Experiment (PSE), the Commercial Protein Crystal Growth (CPCG-Block 2), the Shuttle Plume Impingement Experiment (SPIE), and the Tank Pressure Control Experiment (TPCE) payloads.
Fricke, Robert W., Jr.↗
Actively Controlled Components
Active Control can help to meet future engine requirements by an active improvement of the component characteristics. The concept is based on an intelligent control logic, which senses actual operating conditions and reacts with adequate actuator action. This approach can directly improve engine characteristics as performance, operability, durability and emissions on the one hand. On the other hand active control addresses the design constrains imposed by unsteady phenomena like inlet distortion, compressor surge, combustion instability, flow separations, vibration and noise, which only occur during exceptional operating conditions. The feasibility and effectiveness of active control technologies have been demonstrated in lab-scale tests. This chapter describes a broad range of promising applications for each engine component. Significant efforts in research and development remain to implement these technologies in engine rig and finally production engines and to demonstrate today s engine generation airworthiness, safety, reliability, and durability requirements. Active control applications are in particular limited by the gap between available and advanced sensors and actuators, which allow an operation in the harsh environment in an aero engine. The operating and performance requirements for actuators and sensors are outlined for each of the gas turbine sections from inlet to nozzle.
W. Horn↗
Arcjet thruster research and technology, phase 1
The objectives of Phase 1 were to evaluate analytically and experimentally the operation, performance, and lifetime of arcjet thrusters operating between 0.5 and 3.0 kW with catalytically decomposed hydrazine (N2H4) and to begin development of the requisite power control unit (PCU) technology. Fundamental analyses were performed of the arcjet nozzle, the gas kinetic reaction effects, the thermal environment, and the arc stabilizing vortex. The VNAP2 flow code was used to analyze arcjet nozzle performance with non-uniform entrance profiles. Viscous losses become dominant beyond expansion ratios of 50:1 because of the low Reynolds numbers. A survey of vortex phenomena and analysis techniques identified viscous dissipation and vortex breakdown as two flow instabilities that could affect arcjet operation. The gas kinetics code CREK1D was used to study the gas kinetics of high temperature N2H4 decomposition products. The arc/gas energy transfer is a non-equilibrium process because of the reaction rate constants and the short gas residence times. A thermal analysis code was used to guide design work and to provide a means to back out power losses at the anode fall based on test thermocouple data. The low flow rate and large thermal masses made optimization of a regenerative heating scheme unnecessary.
Knowles, Steven C.↗
Human-in-the-loop evaluation of RMS Active Damping Augmentation
Active Damping Augmentation is the insertion of Controls-Structures Integration Technology to benefit the on-orbit performance of the Space Shuttle Remote Manipulator System. The goal is to reduce the vibration decay time of the Remote Manipulator System following normal payload maneuvers and operations. Simulation of Active Damping Augmentation was conducted in the realtime human-in-the-loop Systems Engineering Simulator at the NASA Johnson Space Center. The objective of this study was to obtain a qualitative measure of operational performance improvement from astronaut operators and to obtain supporting quantitative performance data. Sensing of vibratory motions was simulated using a three-axis accelerometer mounted at the end of the lower boom of the Remote Manipulator System. The sensed motions were used in a feedback control law to generate commands to the joint servo mechanisms which reduced the unwanted oscillations. Active damping of the Remote Manipulator System with an attached 3990 lb. payload was successfully demonstrated. Six astronaut operators examined the performance of an Active Damping Augmentation control law following single-joint and coordinated six-joint translational and rotational maneuvers. Active Damping Augmentation disturbance rejection of Orbiter thruster firings was also evaluated. Significant reductions in the dynamic response of the 3990 lb. payload were observed. Astronaut operators recommended investigation of Active Damping Augmentation benefits to heavier payloads where oscillations are a bigger problem (e.g. Space Station Freedom assembly operators).
Demeo, Martha E.↗
Evaluation of HVAC & refrigeration system fault behaviors and impacts: A systematic review
Achieving the goals of green buildings critically depends on the fault-free operation of heating, ventilation and air conditioning and refrigeration (HVAC&R) systems. However, faults frequently occur in these systems, causing a range of negative consequences, including increased energy consumption, diminished operational performance, compromised indoor environmental quality, higher operational costs, and shortened system lifespan. The evaluation of fault behaviors and impacts plays a critical role in revealing fault characteristics and consequently supports many research areas, including the design of the high-performance equipment, development of fault detection and diagnostics (FDD) and robust control approaches, as well as the enhancement of maintenance decision-making activities. This paper systematically reviews 112 research publications that reported the analysis and evaluation of fault behaviors and impacts in HVAC&R systems over the past thirty years. Here, we designed a review approach to address five crucial research questions, namely: 1) the objectives of analysis and evaluation of fault behaviors and impacts, 2) data sources, 3) equipment/system types and fault types, 4) evaluation methods including evaluation measures and associated metrics, and 5) challenges and future directions in the research on evaluating of fault behaviors and impacts. In-depth discussions on these questions help bridge the gap between the evaluation of fault behaviors and impacts and their practical applications, such as the development of high-performance systems, fault models, FDD methods, and maintenance decision-making tools within the HVAC&R FDD domain.
Chen, Yimin [Oak Ridge National Laboratory (ORNL),↗
An Exploratory Evaluation of UAS Detect and Avoid Operations in the Terminal Environment
New technical standards for Unmanned Aircraft Systems (UAS) detect and avoid (DAA) systems mark recent progress toward realizing the goal of full integration of UAS into the National Airspace System (NAS). The DAA system is intended to provide a means of compliance with operating regulations that required pilots on board manned aircraft to remain "well clear" of other aircraft which is accomplished through out-the-window visual acquisition of other aircraft and application of a subjective judgment of safe separation. The requirements for the DAA system, including the specification of a DAA well clear threshold as well as functional requirements for detecting, tracking, alerting and guidance processing, and displays, are specified in DO-365, Minimum Operational Performance Standards (MOPS) for DAA Systems developed within RTCA Special Committee 228 (SC-228). Intended as the first in a series of phased versions, these requirements are frequently referred to as the "Phase 1" DAA system. The Phase 1 DAA system is limited for use by aircraft transitioning to and from Class A or special use airspace, through Class D, E, and G airspace. In particular, the Phase 1 DAA MOPS are not intended for terminal airspace operations, a critical gap for enabling a full range of UAS operations. The application of the Phase 1 DAA system and DAA well clear threshold within the terminal area is predicted to result in a high number of unnecessary alerts when the UAS is safely separated from other traffic. The goal of the present study was to examine pilot performance and operational issues related to the operation of the Phase 1 DAA system in a terminal area. This experiment was intended as an exploratory study that would be used to inform the development of a new terminal area-specific DAA well clear definition, and associated alerting and guidance requirements. The two main objectives of this study were to: 1) characterize pilot behavior in the terminal environment with the Phase 1 DAA system, and 2) investigate the effect of modifications to the Phase 1 DAA alerting and guidance structure. In particular, the authors were interested in determining whether the removal of specific alerting and guidance levels, without changing the DAA well clear definition or alerting thresholds, would impact pilot performance while conducting terminal operations. The results indicate that the Phase 1 well clear definition and alerting and guidance resulted in frequent alerting that degraded pilots' ability to discriminate between encounters where another aircraft was safely separated versus when a maneuver was necessary. The resulting impact on pilot performance was slower response times and higher frequency and severity of losses of DAA well clear compared to those observed for experiments examining pilot performance in the en route environment. There was no significant effect of alerting and guidance display configuration on pilot performance.
Rorie, Conrad↗
An Exploratory Evaluation of UAS Detect and Avoid Operations in the Terminal Environment
New technical standards for Unmanned Aircraft Systems (UAS) detect and avoid (DAA) systems mark recent progress toward realizing the goal of full integration of UAS into the National Airspace System (NAS). The DAA system is intended to provide a means of compliance with operating regulations that required pilots on board manned aircraft to remain "well clear" of other aircraft which is accomplished through out-the-window visual acquisition of other aircraft and application of a subjective judgment of safe separation. The requirements for the DAA system, including the specification of a DAA well clear threshold as well as functional requirements for detecting, tracking, alerting and guidance processing, and displays, are specified in DO-365, Minimum Operational Performance Standards (MOPS) for DAA Systems developed within RTCA (Radio Technical Commission for Aeronautics) Special Committee 228 (SC-228). Intended as the first in a series of phased versions, these requirements are frequently referred to as the "Phase 1" DAA system. The Phase 1 DAA system is limited for use by aircraft transitioning to and from Class A or special use airspace, through Class D, E, and G airspace. In particular, the Phase 1 DAA MOPS are not intended for terminal airspace operations, a critical gap for enabling a full range of UAS operations. The application of the Phase 1 DAA system and DAA well clear threshold within the terminal area is predicted to result in a high number of unnecessary alerts when the UAS is safely separated from other traffic. The goal of the present study was to examine pilot performance and operational issues related to the operation of the Phase 1 DAA system in a terminal area. This experiment was intended as an exploratory study that would be used to inform the development of a new terminal area-specific DAA well clear definition, and associated alerting and guidance requirements. The two main objectives of this study were to: 1) characterize pilot behavior in the terminal environment with the Phase 1 DAA system, and 2) investigate the effect of modifications to the Phase 1 DAA alerting and guidance structure. In particular, the authors were interested in determining whether the removal of specific alerting and guidance levels, without changing the DAA well clear definition or alerting thresholds, would impact pilot performance while conducting terminal operations. The results indicate that the Phase 1 well clear definition and alerting and guidance resulted in frequent alerting that degraded pilots' ability to discriminate between encounters where another aircraft was safely separated versus when a maneuver was necessary. The resulting impact on pilot performance was slower response times and higher frequency and severity of losses of DAA well clear compared to those observed for experiments examining pilot performance in the en route environment. There was no significant effect of alerting and guidance display configuration on pilot performance.
terminal area↗
Analysis and Selection of a Remote Docking Simulation Visual Display System
The development of a remote docking simulation visual display system is examined. Video system and operator performance are discussed as well as operator command and control requirements and a design analysis of the reconfigurable work station.
Shields, N., Jr.↗
Rubidium and cesium frequency standards status and performance on the GPS program
The on-oribt operational performance of the frequency standards on the Global Positioning System (GPS) 1 to 10 NAVSTAR satellites are discussed. The history of the Rb frequency standards showing the improvements incorporated at various stages of the program and the corresponding results are presented. Also presented is the operational history of the NAVSTAR cesium frequency standards. The frequency standards configuration data presented covers the chronology of events from the concept validation satellites, NAVSTAR 1 to 10, starting in 1978 to the present, including the configurations of clocks to be used on the GPS Production Program. Data are presented showing the results of long-term laboratory testing of a production Rb frequency standard with the necessary data taken to calculate Delta F, drift, time error, and Allan variance.
Bethke, H.↗