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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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At least 199 records · Page 11

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NASA NTRS1979

Solar heating system installed at Stamford, Connecticut

The solar heating system installed at the Lutz-Sotire Partnership Executive East Office Building, Stamford, Connecticut is described. The Executive East Office Building is of moderate size with 25,000 sq ft of heated space in 2 1/2 stories. The solar system was designed to provide approximately 50 percent of the heating requirements. The system components are described. Appended data includes: the system design acceptance test, the operation and maintenance manual, and as-built drawings and photographs.

Source record↗

NASA NTRS1983

Structural coverage of functional testing

A FORTRAN program was instrumened to produce structural coverage measures. The structural coverage profiles of functionally generated acceptance tests and operational usage are used to examine two areas in software engineering: the examination of faults and the applicability of reliability models.

Ramsey, J.↗

NASA NTRS1986

Response modalities and time-sharing performance

An experiment performed to investigate the role of resource competition and asymmetric transfer in dual-task performance is described. It is shown that there is an advantage to mixed manual/speech response modality configurations that cannot be accounted for by asymmetric transfer. The present results support the multiple resources approach to the application of speech technology. Once speech recognition achieves an acceptable level of operational reliability, speech controls can be used to reduce resource competition and improve performance in multitask environments.

Vidulich, Michael A.↗

NASA NTRS1988

VICAR/IBIS Software System

Collection of programs provides extensive capabilities for manipulation of imagery and geographical data. VICAR/IBIS software system is combination of JPL VICAR (Video Image Communications and Retrieval System) image-processing system and JPL IBIS (Image Based Information System) geographic-information-management system. Provides user with extensive general-purpose image-processing capabilities, also information-management system for accepting, converting, and operating on vector (graphical) and tabular data. System used to perform various image processing functions on any sort of digitized image data, including such remotely sensed data as those from Landsat multispectral scanner.

Stanfill, Daniel F., IV↗

NASA NTRS1988

Mental workload dynamics in adaptive interface design

In examining the role of time in mental workload, the authors present a different perspective from which to view the problem of assessment. Mental workload is plotted in three dimensions, whose axes represent effective time for action, perceived distance from desired goal state, level of effort required to achieve the time-constrained goal. This representation allows the generation of isodynamic workload contours that incorporate the factors of operator skill and equifinality of effort. An adaptive interface for dynamic task reallocation is described that uses this form of assessment to reconcile the joint aims of stable operator loading and acceptable primary task performance by the total system.

Hancock, Peter A.↗

NASA NTRS1992

Planning And Reasoning For A Telerobot

Document discusses research and development of Telerobot Interactive Planning System (TIPS). Goal in development of TIPS is to enable it to accept instructions from operator, then command run-time controller to execute operations to execute instructions. Challenges in transferring technology from testbed to operational system discussed.

Peters, Stephen F.↗

NASA NTRS1995

Tunnel-Junction Mixers Perform Well At 205 GHz

Superconductor-Insulator Superconductor (SIS) tunnel junctions made of NbN/MgO/NbN and Nb/AlOx/Nb, with cross-sectional areas of about 0.30 and 0.25 micrometer(Sup2) respectively, fabricated and tested for use as mixers at frequencies near 205 GHz. Cross sections must be small to make capacitances of devices acceptably small for operation at this frequency. NbN and Nb good materials choices as superconductors because of high energy gap, and mechanically and electrically rugged and chemically stable.

Javadi, Hamid H. S.↗

NASA NTRS1997

New Approaches to Waterproofing of Space Shuttle Insulating Materials

Future reusable space vehicles will be in service much more frequently than current space shuttles. Therefore, rapid reconditioning of spacecraft will be required. Currently, the waterproofing of space shuttles after each re-entry takes 72 hours and requires substantial labor. In addition, the currently used waterproofing reagent, DiMethylEthoxySilane (DMES), is considered toxic, and ethanol fumes are released during its hydrolytic activation. Consequently, a long time period, which is not acceptable for future operations, is needed to ensure that 0 the excess volatile compounds are removed before further maintenance of the space vehicle can be performed. The objective of this project was to assist NASA Ames in finding improved waterproofing systems by identifying suitable waterproofing agents that can be applied by vapor phase deposition and will be less toxic, bond more rapidly to the insulation material surface, and potentially have higher thermal stability than the DMES system. Several approaches to achieve faster waterproofing with less toxicity were assessed using the following alternatives: Reactive volatile compounds that are rapidly deposited by chemical bonding at the surface and leave no toxic volatiles. Reactive reagents that are the least toxic. Nonvolatile reagents that are very reactive and bond strongly to the insulating material surface. Three specific types of potential reagents were chosen for evaluation in this project: 1. Volatile reagents with Si-Cl functional groups for vapor deposition 2. Volatile reagents with Si-H functional groups for vapor deposition 3. Nonvolatile oligomeric or polymeric reactive siloxanes that are assumed to have higher thermal stability and/or strong bonding to the insulating material. The chemistry involved in the project was targeted at the generation of intermediates having reactive Si-OH bonds for the formation of either volatile species or polymeric species that bond rapidly to the surface and also cure rapidly. We focused on two chemical reactions@-hydrolysis of Si-Cl bonds and catalytic dehydrocoupling of Si-H bonds.

Blum, Yigal D.↗

NASA NTRS1961

A Study of Longitudinal Control Problems at Low and Negative Damping and Stability with Emphasis on Effects of Motion Cues

As part of a general investigation to determine the effects of simulator motions on pilot opinion and task performance over a wide range of vehicle longitudinal dynamics, a cooperative NASA-AMAL program was conducted on the centrifuge at Johnsville, Pennsylvania. The test parameters and measurements for this program duplicated those of earlier studies made at Ames Research Center with a variable-stability airplane and with a pitch-roll chair flight simulator. Particular emphasis was placed on the minimum basic damping and stability the pilots would accept and on the minimum dynamics they considered controllable in the event of stability-augmentation system failure. Results of the centrifuge-simulator program indicated that small positive damping was required by the pilots over most of the frequency range covered for configurations rated acceptable for emergency conditions only (e.g., failure of a pitch damper). It was shown that the pilot's tolerance for unstable dynamics was dependent primarily on the value of damping. For configurations rated acceptable for emergency operation only, the allowable instability and damping corresponded to a divergence time to double amplitude of about 1 second. Comparisons were made of centrifuge, pitch-chair and fixed-cockpit simulator tests with flight tests. Pilot ratings indicated that the effects of incomplete or spurious motion cues provided by these three modes of simulation were important only for high-frequency, lightly damped dynamics or unstable, moderately damped dynamics. The pitch- chair simulation, which provided accurate angular-acceleration cues to the pilot, compared most favorably with flight. For the centrifuge simulation, which furnished accurate normal accelerations but spurious pitching and longitudinal accelerations, there was a deterioration of pilots' opinion relative to flight results. Results of simulator studies with an analog pilot replacing the human pilot illustrated the adaptive capability of human pilots in coping with the wide range of vehicle dynamics and the control problems covered in this study. It was shown that pilot-response characteristics, deduced by the analog-pilot method, could be related to pilot opinion. Possible application of these results for predicting flight-control problems was illustrated by means of an example control-problem analysis. The results of a brief evaluation of a pencil-type side-arm controller in the centrifuge showed a considerable improvement in the pilots' ability to cope with high-frequency, low-damping dynamics, compared to results obtained with the center stick. This improvement with the pencil controller was attributed primarily to a marked reduction in the adverse effects of large and exaggerated pitching and longitudinal accelerations on pilot control precision.

Sadoff, Melvin↗

NASA NTRS1999

Investigation of Wake-Vortex Aircraft Encounters

The National Aeronautics and Space Administration is addressing airport capacity enhancements during instrument meteorological conditions though the Terminal Area Productivity (TAP) program. The major goal of the TAP program is to develop the technology that will allow air traffic levels during instrument meteorological condition to approach those achieved during visual operations. The Reduced Spacing Operations (RSO) subelement of TAP at the NASA Langley Research Center (LaRC) will develop the Aircraft Vortex Spacing System (AVOSS). The purpose of the AVOSS is to integrate current and predicted weather conditions, wake vortex transport and decay knowledge, wake vortex sensor data, and operational definitions of acceptable strengths for vortex encounters to produce dynamic wake vortex separation criteria. The proposed research is in support of the wake vortex hazard definition component of the LaRC AVOSS development research. The research program described in the next section provided an analysis of the static test data and uses this data to evaluate the accuracy vortex/wake-encounter models. The accuracy of these models has not before been evaluated using experimental data. The research results also presented the first analysis of the forces and moments imparted on an airplane during a wake vortex encounter using actual flight test data.

Smith, Sonya T.↗

NASA NTRS2010

A Controller-in-the Loop Simulation of Ground-Based Automated Separation Assurance in a NextGen Environment

A controller-in-the-loop simulation was conducted in the Airspace Operations Laboratory (AOL) at the NASA Ames Research Center to investigate the functional allocation aspects associated with ground-based automated separation assurance in a far-term NextGen environment. In this concept, ground-based automation handled the detection and resolution of strategic and tactical conflicts and alerted the controller to deferred situations. The controller was responsible for monitoring the automation and managing situations by exception. This was done in conditions both with and without arrival time constraints across two levels of traffic density. Results showed that although workload increased with an increase in traffic density, it was still manageable in most situations. The number of conflicts increased similarly with a related increase in the issuance of resolution clearances. Although over 99% of conflicts were resolved, operational errors did occur but were tied to local sector complexities. Feedback from the participants revealed that they thought they maintained reasonable situation awareness in this environment, felt that operations were highly acceptable at the lower traffic density level but were less so as it increased, and felt overall that the concept as it was introduced here was a positive step forward to accommodating the more complex environment envisioned as part of NextGen.

Homola, J.↗

NASA NTRS2004

A Portable Electronic Nose For Hydrazine and Monomethyl Hydrazine Detection

The Space Program and military use large quantities Hydrazine (Hz) and monomethyl hydrazine (MMI-I) as rocket propellant. These substances are very toxic and are suspected human carcinogens. The American Conference of Governmental Industrial Hygienist set the threshold limit value to be 10 parts per billion (ppb). Current off-the-shelf portable instruments require 10 to 20 minutes of exposure to detect 10 ppb concentration. This shortcofriing is not acceptable for many operations. A new prototype instrument using a gas sensor array and pattern recognition software technology (i.e., an electronic nose) has demonstrated the ability to identify either Hz or MM}{ and quantify their concentrations at 10 parts per billion in 90 seconds. This paper describes the design of the portable electronic nose (e-nose) instrument, test equipment setup, test protocol, pattern recognition algorithm, concentration estimation method, and laboratory test results.

Young, Rebecca C.↗

NASA NTRS2015

Recommended Screening Practices for Launch Collision Aviodance

The objective of this document is to assess the value of launch collision avoidance (COLA) practices and provide recommendations regarding its implementation for NASA robotic missions. The scope of this effort is limited to launch COLA screens against catalog objects that are either spacecraft or debris. No modifications to manned safety COLA practices are considered in this effort. An assessment of the value of launch COLA can be broken down into two fundamental questions: 1) Does collision during launch represent a significant risk to either the payload being launched or the space environment? 2) Can launch collision mitigation be performed in a manner that provides meaningful risk reduction at an acceptable level of operational impact? While it has been possible to piece together partial answers to these questions for some time, the first attempt to comprehensively address them is documented in reference (a), Launch COLA Operations: an Examination of Data Products, Procedures, and Thresholds, Revision A. This report is the product of an extensive study that addressed fundamental technical questions surrounding launch collision avoidance analysis and practice. The results provided in reference (a) will be cited throughout this document as these two questions are addressed. The premise of this assessment is that in order to conclude that launch COLA is a value-added activity, the answer to both of these questions must be affirmative. A "no" answer to either of these questions points toward the conclusion that launch COLA provides little or no risk mitigation benefit. The remainder of this assessment will focus on addressing these two questions.

recommended screening practicies luanch collision ↗

NASA NTRS2016

Toward a Safety Risk-Based Classification of Unmanned Aircraft

There is a trend of growing interest and demand for greater access of unmanned aircraft (UA) to the National Airspace System (NAS) as the ongoing development of UA technology has created the potential for significant economic benefits. However, the lack of a comprehensive and efficient UA regulatory framework has constrained the number and kinds of UA operations that can be performed. This report presents initial results of a study aimed at defining a safety-risk-based UA classification as a plausible basis for a regulatory framework for UA operating in the NAS. Much of the study up to this point has been at a conceptual high level. The report includes a survey of contextual topics, analysis of safety risk considerations, and initial recommendations for a risk-based approach to safe UA operations in the NAS. The next phase of the study will develop and leverage deeper clarity and insight into practical engineering and regulatory considerations for ensuring that UA operations have an acceptable level of safety.

Torres-Pomales, Wilfredo↗

NASA NTRS2020

Honeywell Enhancing Airplane State Awareness (EASA) Project: Final Report on Refinement and Evaluation of Candidate Solutions for Airplane System State Awareness

The loss of pilot airplane state awareness (ASA) has been implicated as a factor in several aviation accidents identified by the Commercial Aviation Safety Team (CAST). These accidents were investigated to identify precursors to the loss of ASA and develop technologies to address the loss of ASA. Based on a gap analysis, two technologies were prototyped and assessed with a formative pilot-in-the-loop evaluation in NASA Langley’s full-motion Research Flight Deck. The technologies address: 1) data source anomaly detection in real-time, and 2) intelligent monitoring aids to provide nominal and predictive awareness of situations to be monitored and a mission timeline to visualize events of interest. The evaluation results indicated favorable impressions of both technologies for mitigating the loss of ASA in terms of operational utility, workload, acceptability, complexity, and usability. The team concludes that there is a feasible retrofit solution for improving ASA that would minimize certification risk, integration costs, and training impact.

Whitlow, Stephen D.↗

NASA NTRSDate not supplied

Advanced Air Mobility Vertiport Considerations: A List and Overview

Advanced air mobility (AAM) is an emerging field in aeronautics that involves utilizing small aircraft for everyday transportation and other services, and many AAM aircraft are envisioned to take off and land at new infrastructure termed vertiports. This paper describes a variety of considerations related to AAM vertiports that need to be considered in the planning for and deployment of vertiports in practice. The factors include siting, design, regulations, safety, environmental impact, social acceptance, equity, and operational integration factors. Over 450 considerations were compiled from Subject Matter Experts (SMEs) participating in NASA’s AAM Ecosystem Working Groups (AEWGs) in October 2021. This paper consolidates these considerations and broadly disseminates the valuable knowledge of these SMEs. These considerations can be used by researchers to conduct demand and network analysis, local transportation planners to develop AAM networks for their community, and the AAM ecosystem members to identify policy, standards, and research gaps.

vertiport considerations↗

NASA NTRSDate not supplied

Control System Development for A Zero Boil-Off Hydrogen Storage Demonstration With Two-Stage Active Cooling

A NASA team is designing and building a test article to demonstrate the long duration storage of liquid hydrogen via active cooling (cryocoolers) while implementing a two-stage cooling approach. This activity is one of a large portfolio of NASA’s Space Technology Mission Directorate funded activities which focuses on the technology maturation needed for long duration storage of cryogenic liquid in-space. The current state-of-the-art for liquid hydrogen storage on-orbit is on the order of hours while NASA’s planned missions require storage for months, or even years. To enable such a long duration, Zero Boil-Off conditions must be achieved which requires passive technologies to minimize environmental heat loads, but also active cooling to intercept and reject the remaining heat to deep space. The implementation of active cooling results in a significant amount of dry mass added to the vehicle. Utilizing a Two-Stage Cooling approach, analysis and testing to date indicates the Zero Boil-Off of liquid hydrogen can be achieved with less mass and electrical power relative to a single-stage cooling approach where only one cryocooler is used. This activity will demonstrate the fully integrated suite of technologies needed to enable the Two-Stage Cooling approach which includes Multi-Layer Insulation blankets, Low Conductivity Structures, a Tube-On-Tank Heat Exchanger, Tube-On-Shield Heat Exchanger and a Two-Stage Cryogenerator (both 90 Kelvin and 20 Kelvin) with each stage having an independently controlled circulation loop. The bulk of the heat load is intercepted by the 90 Kelvin loop via a thin foil heat exchanger internal to the insulation blankets (also known as a Broad Area Cooling Shield), with the remainder removed at cryofluid temperature (20 Kelvin) by tubes directly welded to the outer tank surface. In this paper, we examine the challenges of controlling the system, and describe the development of control algorithms and software for future testing with liquid hydrogen. The interactions between the cryofans which control circulation loop mass flow rates, electrical heaters which vary the cryocooler lift to simulate the operation of variable-lift flight units, tank heaters which can vary the overall heat load, and the effects of changes in circulation loop pressure as temperatures change, can be complex and must be well understood to maintain steady-state propellant conditions and achieve Zero Boil-Off. Parallel PID loops and watchdog programs implemented on the user interface system will help bring the systems to steady state operation and keep them at selected operating points within acceptable error, while avoiding runaway feedback loops.

cryogenics↗

NASA NTRS2023

Desert Research and Technology Studies (D-RATS) 2022 Test Report

The primary purpose of the 2022 Desert Research and Technology Studies (D-RATS 22) analog mission field test was to provide data and recommendations regarding how pressurized rover (PR) design, cabin configuration, driving modes, timeline constraints, and mission operations can be acceptably implemented to support future Artemis missions that include a PR. The goal of these evaluations was to provide first order feedback and data on design concepts currently being traded as options for future pressurized rover flight prototypes. The Japan Aerospace Exploration Agency (JAXA) may provide a PR for future Artemis missions. One of the primary objectives of D-RATS 2022 was to share with the JAXA PR team the processes and protocols by which NASA has learned to successfully evaluate rover concepts through integrated HITL evaluations over the past 20+ years, so that JAXA could apply any applicable lessons learned to their PR design, development, testing, and evaluation.

analog↗